Shaochen Chen - US grants

This Faculty Early Career Development ( CAREER) project integrates research and educational initiatives focusing on micro- and nano-scale processing of biodegradable polymers using laser techniques for biomedical and bioMEMS applications. Research focusing on laser micro- and nano-scale processing with parametric studies using both a UV excimer laser and a femtosecond laser to produce controlled micro-features on polymer surfaces will be addressed. Biodegradable polymers hold immense promise as new materials for implantable biomedical micro-devices due to their biocompatibility and ability to naturally degrade and disappear in tissues over a desired period of time. This degradability eliminates a second surgery to retrieve the implanted micro-devices. The CAREER project will: (1) develop an advanced laser technique with a near-field beam delivery system to produce controlled micro- and nano-scale patterns on biodegradable polymer surfaces; (2) develop an experimental system and a numerical model to investigate the transient laser-material interaction process on extremely small time and length scales; and (3) implement the research into the development of biodegradable micro- and nano-devices. This research will make significant contribution to the emerging and interdisciplinary field of micro- and nano-manufacturing science and technology, bioengineering, and polymer science.

The integrated education plan will focus on curriculum development in micro- and nano-manufacturing at the undergraduate and graduate levels by infusing emerging and multi-disciplinary research into the classroom. This plan also encourages women students in research and adopts cooperative learning techniques in teaching. The PI also incorporates a learning plan for himself in new methods of educational pedagogy and curriculum development.

The proposal was submitted in response to the FY2002 Chemical and Transport Systems equipment solicitation, described in NSF Announcement. NSF 01-93. The PIs propose to acquire two pieces of equipment that will establish a significant experimental capability in micro/nanoscale transport phenomena at the University of Texas at Austin. Research activities enabled by this equipment include thermal property measurements of nanostructures and in low conductivity dielectric films, investigation of heat dissipation mechanisms in carbon nanotubes, and near-field laser manufacturing and nanoscale fluorescence imaging. Application of these nanostructures, including carbon nanotubes and semiconductor nanowires, in the areas o nanoelectronics, optoelectronics, and thermoelectric cooling has great technological potoential. The equipment will also be utilized in new graduate courses at U.T.-Austin. Funding is from the Thermal Transport and Thermal Processing of the Chemical and Transport Systems Division.

Nanoparticles are among the most important nanomaterials in nanoscience and nanoengineering. Innovative applications of these nanoparticles in an engineering system such as nanosphere-enhanced photolithography are emerging. However, little is known about the physics of the process, especially the optical and thermal transport issues involving extremely small length and time scales. This project will offer comprehensive investigations on the laser-nanosphere interaction process by a combination of experimental techniques and theoretical simulation, including ultrafast laser interaction with the nanospheres resting on a solid substrate, conduction and radiative heat transfer between the nanopsheres and the substrate, as well as surface nanostructuring as a result of the nanoscale optical interaction and heat transfer. From this research, a practical nanolithography tool will be developed for massively parallel nanomanufacturing of a variety of materials.

Results from this project will make a significant impact on the interdisciplinary field of nanoscale thermal transport, nanooptics, and nanomanufacturing. Moreover, the results of this work will provide exciting teaching materials and interesting lab projects for undergraduates, graduate students, and K-12 students and teachers.

The award has been funded jointly by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division and by the Nanomanufacturing Program of the Division of Design, Manufacturing and Industrial Innovation.

The objective of this project, to be conducted at the University of Texas at Austin, is to develop a new nano-fabrication technique, Surface Plasmons-Assisted Nanolithography (SPAN), to manufacture sub-50 nm structures in a massively parallel fashion. The PI will conduct comprehensive investigations by a combination of experiments and theoretical simulation to obtain a fundamental understanding of enhanced optical transmission through nano-slits and photoresist. Optimal design of the SPAN process using different mask materials, photoresists, and coating on the substrate will be carried out aiming to address the underlying necessities for predictability, producibility, and productivity using SPAN. The proposed research requires the unique combination of nano-photonics and nanomanufacturing.

As a general purpose nanomanufacturng technique, the technical impact of the SPAN process will be very broad, ranging from the fabrication of nanoelectronics, to the development of nanophotonics and nano-bio systems. Compared to existing nano-fabrication techniques, this new method offers high throughput and low costs, which are critical to industrial scale manufacturing. Moreover, the results of this work will provide exciting teaching materials and interesting laboratory projects. The proposed efforts of integrating research with education will offer undergraduates and graduate students increased exposure to nanoscience and engineering technologies and applications. In particular, improving on-going graduate courses in NEMS/MEMS, initiation of a new undergraduate course -Introduction to Micro and Nanoengineering", and implementation of emerging nanoengineering components into traditional undergraduate core courses will have a significant impact on graduate and undergraduate education.

The objective of this research is to develop an efficient, accurate, and low-cost laser direct-write process for fabricating a sub-micron dent array on precision components to enhance fatigue performance. A synergistic experimental, theoretical, and computational study will be conducted. The research approach is to develop a massively parallel laser direct-write process for fabricating a sub-micron dent array on precision surfaces, and create a finite element analysis model to capture mechanical behaviors at pertinent small scales to understand the mechanisms of laser/material interactions and predict dent geometry, transient and residual stress, and surface material properties. Surface integrity will be comprehensively characterized, including surface finish, dent geometry, residual stress, micro/nano hardness and modulus, and microstructures. Rolling contact fatigue tests at both lab and production scales will be conducted to determine the effects of a sub-micron dent array on component fatigue life. Finally, a physics-based finite element simulation model of rolling contact will be developed to elucidate fatigue damage mechanisms in the presence of a sub-micron dent array.

This project will create a new knowledge base of laser processing for manufacturing precision components. The broad impact includes an efficient and cost-effective surface treatment process for making micro surface structures with high efficiency, high accuracy, and low cost to meet production needs. The research supports the economy by improving the U.S. position in the manufacturing industry. This collaborative research will enrich the education infrastructure, promote facility sharing, disseminate research results, and enhance collaboration and technology transfer between researchers and educators at academia and industry. In addition, this research fosters ongoing outreach activities, including Shelton State University and Stillman Community College in Tuscaloosa, Alabama and Austin Community College in Austin, Texas, to undergraduates from groups that are underrepresented in science and engineering.

The objective of this Nanoscale Interdisciplinary Research (NIRT) project is to establish an interdisciplinary research and education program in the area of nanomanufacturing for the fabrication of active photonics-on-chip where optical properties can be controlled either optically, magnetically or electro-optically. Several approaches will be combined to enable fabrication of photonic bandgap crystals and active photonic devices. Imprint lithography will be employed to create two-dimensional photonic crystals containing point defects for creation of the cavity of laser sources and line defects for planar waveguides. Three-dimensional photonic crystals will be fabricated through multi-beam holographic lithographic techniques in which all beams come from the same half-space. Two-photon stereolithography will then be used to fabricate defects inside the three-dimensional photonic crystal for optical processing. The two-dimensional and three-dimensional photonic bandgap crystals will be hybridized to form a photonic band gap heterostructure containing engineered defects, which enables active control of light generation, photon propagation, and photon signal processing in optical circuits.

If these technologies are successful, the economies and scaling of today's silicon electronics can be carried forward into tomorrow's silicon photonics. Overall, these technologies can make optical circuit manufacturing commercially feasible and contribute to the United States' global competitiveness in photonics technology. University of Texas-Pan American (UTPA) is a minority university which is second in the nation in the number of bachelor's degrees awarded to Hispanics. Through this collaborative project, UTPA professors and students can access the unique facilities at the University of Texas at Austin, one of the top-ranked and best-equipped Universities in Texas. The research will offer an excellent opportunity for Hispanic students to engage in multi-disciplinary research and to pursue advanced degrees, increasing the number of under-represented scientists.

DESCRIPTION (provided by applicant): The long term goal of our research is to design complex biomaterial scaffolds that can mimic the micro- architecture of cardiac tissues and to augment regeneration therapies. These tissue-like structures will have the appropriate microarchitectural features of native tissues including a functioning vasculature. To fabricate these tissues we are interested in using natural molecules such as hyaluronic acid (HA;also called hyaluronan)-based biomaterials, because of the ubiquitous presence of HA in the extracellular matrix (ECM) of tissues and the significant role that HA inherently plays in wound healing. The objective of the proposed research is to develop methods to create 3D scaffolds of native ECM components with complex internal architecture and cell encapsulation. To fabricate such scaffolds, we will develop an innovative direct-write platform based on a projection-style stereolithographic (SL) method, coined as PSL. In Specific Aim 1, we will develop and optimize the PSL system for the fabrication of 3D microstructures using HA with Arg-Gly-Asp (RGD) and matrix metalloproteinase (MMP). In Specific Aim 2, we will use PSL for Direct-write 3D HA scaffolds encapsulating cardiomyocytes. In Specific Aim 3, we will create vascularized structures in a 3D scaffold and analyze vasculature functions. We will seed an endothelial cell lining within microchannels. The seeding process will be optimized by adjusting the cell seeding density and duration as well as surface chemistry. The vascular function and biomechanical properties of these engineered tissue constructs will be determined in vitro. PUBLIC HEALTH RELEVANCE: This project seeks to develop a novel biofabrication platform to create three-dimensional (3D) scaffolds of native extracellular matrix components with complex internal architectures and cell encapsulation. The goal of the project is to create vascularized structures in the 3D scaffolds

Diabetes, heart failure, and hepatic failure are diseases of enormous burden to Americans. The effective therapies for these often lethal diseases require the application of novel engineering concepts and technologies. Tissue engineering holds great promise for the treatment of these diseases. Using biodegradable scaffolds, cells are organized in close proximity to each other with a well-defined 3-dimensional (3D) space for the formation of new tissues. While a typical biological cell has a size of several microns, the interactions of cells with the environment occur at a nanoscale. Fabricating such scaffolds with micro- and nano-scale features has been a significant bottleneck for industrial scale production of tissues. The goal of this research is to develop a novel nanomanufacturing system, Hyperlens-Assisted Projection Stereolithography (HAPS), with a sub-50 nm resolution for the direct-write of 3D, heterogeneous biological scaffolds. The research tasks include: a) design and fabrication of the hyperlens by combining simulation with experiments, b) integration of the hyperlens with the projection stereolithography system, c) design and fabrication of complex tissue scaffolds, and d) studying the growth and phenotypical modulation of vascular endothelial cells and smooth muscle cells using the scaffolds.

If successful, this project will help to enhance the emerging US biomanufacturing industry for the production of vascular tissues, skins, bones, and other tissues and organs. The proposed HAPS technique will foster a giant step for scalable, continuous 3D nanomanufacturing of not only functional biomedical devices, but also 3D nanoelectronics, nanophotonics, and nanoenergy devices. Moreover, the results of this work will provide inspiring teaching materials and interesting laboratory projects. The proposed efforts of integrating research with education will offer undergraduates and graduate students increased exposure to nanomanufacturing. The proposed symposia and workshop will greatly enhance the impact of nanomanufacturing research.

This grant provides funding to study fundamental phenomena of laser-gas-polymer interaction, with a goal to develop an innovative fabrication process for biochip devices that will enable high-throughput, organotypic cell-based diagnostics. The proposed research combines the processing capability of nano-/femtosecond lasers and a solvent-free gas foaming technique to create a large array of miniaturized three-dimensional tissue engineering scaffolds on a polymer chip. While extremely localized heat will be generated to create the porous structure, precision laser machining will be employed to shape the scaffolds and engrave microfluidic channels. Both theoretical and experimental studies will be conducted to understand the mechanisms of the proposed process, including laser heating, ablation, and bubble nucleation and growth in gas impregnated polymer. A sequentially coupled numerical model will be developed to study the nonlinear effects in the laser heating and bubble formation process. A biocompatibility study of the fabricated device will also be conducted.

If successful, the results of this research will lead to a novel manufacturing process to create organotypic microarrays that could offer a completely ethical alternative to using animals and humans in drug screening. Current two-dimensional cell culture conditions yield monolayers that are poor mimics of the in vivo cellular microenvironment. The fabrication process developed in this research will enable realistic three-dimensional tissue analogs built into a large array for high throughput, parallel interrogation of drug candidates. The proposed research explores complex interaction among laser, polymer, and gas bubbles. Findings of this research will add to the scientific knowledge base in laser material processing, a strategic area in advanced manufacturing that helps maintain the US leading position in the world. The proposed research will not only stimulate scientific discovery, but also provide opportunities for student training and technology transfer.

DESCRIPTION (provided by applicant): In the U.S., liver associated diseases are major contributors to morbidity and mortality. Approximately 40,000 people in the U.S. die each year from acute or chronic liver diseases. Liver tissue engineering has made significant progress towards the creation of in vitro liver models for drug screening, as well as in vivo constructs for addressing the large clinical need for transplant sources. However, cell sourcing remains a significant challenge for both in vivo and in vitro liver models. Human induced pluripotent stem cells (iPSCs) are a promising technology in regenerative medicine as they can be autologously derived, maintain high proliferative capacity, and demonstrate enormous differentiation potential, while also mitigating the ethical concerns associated with the use of embryonic stem cells (ESCs). However, the application of iPSCs towards functional in vitro tissue models is still largely under development, and tissue-engineered constructs for in vivo transplantation have yet to be fully realized. To address these challenging issues, we propose to develop a functional in vitro micro-liver model via encapsulation of pre-differentiated iPSCs using a novel 3D bioprinting technique. This model will be subsequently enhanced through the addition of physiologically related components (i.e. co-cultures with supportive cells) to provide an advanced liver-on-a-chip model that can be studied further. The liver associated functions of the liver-on-a-chip models will be systematically examined. In Specific Aim 1, we will develop a liver-on-a-chip model by encapsulating iPSC-derived hepatic progenitor cells within 3D biomimetic scaffolds. In Specific Aim 2, we propose to incorporate biologically related supportive cell types into the liver on-a-chip model. To accomplish our goal, we have assembled the collaborative talents of three experts, including Chen for biofabrication and tissue engineering, Wang for iPSCs, and Feng for hepatocellular function and liver biology. We envision that our patient specific liver-on-a chip model can be explored as a reliable and cost-efficient in vitro platform to facilitate drug metabolism studies, preclinical drug screening, and fundamental hepatology research.

The research objective of this award is to create a new class of nanostructured biological scaffolds that exhibit a negative Poisson's ratio (auxetic surfaces), and study their ability to modulate the cell shape, adhesion, proliferation and cytoskeletal re-orientation. The ability of a biomaterial scaffold to support and transmit cell and tissue forces can be quantitatively described by its elastic modulus and Poisson's ratio. Recent studies have shown that elastic modulus can modulate a variety of cell types. However, the effect of Poisson's ratio on cell behavior has been largely ignored. While most natural materials have a positive Poisson's ratio and contract (expand) transversally when stretched (compressed) in a certain direction, auxetic materials exhibit an unusual property of having a negative Poisson's ratio, i.e., they expand transversally when stretched and vice versa. To achieve the research objectives, the team will design, fabricate, and characterize nanoscale auxetic surface topographies that exhibit a negative Poisson's ratio using polyethylene glycol biomaterial. The team will investigate the auxetic effect in the nanoscaffolds on the adhesion, cytoskeletal organization, and shape of adipose derived human stem cells. If successful, this work will be the first in the field for developing nanoscale scaffolds with a negative Poisson's ratio and studying the cellular responses to such novel scaffolds. The PI has an outstanding track record of research in nanofabrication, biomaterials, and cell interactions with microenvironments. UC San Diego and the PI's laboratories offer excellent facilities and resources for this project.

An auxetic scaffold could match both the elastic stiffness and the Poisson's ratio of the host tissue and would likely better integrate with native tissues and better promote clinical tissue regeneration. Methodology developed in this work can be extended to other biomaterials and cell-types to investigate effects of altering the Poisson's ratio on a variety of cellular aspects for arterial endothelium, myocardial patch, skin and fat tissue engineering, medical sutures, and in wound management. Thus this work directly aids scientific progress, benefits healthcare and society at large. The proposed research is highly interdisciplinary, involving tissue engineering, nanomanufacturing, and biomaterials. Results from this project will be excellent teaching materials for undergraduate and graduate students. The strong educational efforts for K-12 and minority students will attract more young students and under-represented students into engineering, and particularly into the interdisciplinary field between engineering and biology.

The San Diego Nanotechnology Infrastructure (SDNI) site of the NNCI at the University of California at San Diego offers access to a broad spectrum of nanofabrication and characterization instrumentation and expertise that enable and accelerate cutting edge scientific research, proof-of-concept demonstration, device and system prototyping, product development, and technology translation. Nanotechnology is the cornerstone of many industry sectors and a rich source for scientific discoveries and innovations. Using nanotechnologies, scientists are likely to find solutions for the most important challenges in health, communications, energy, and environment. Nanotechnology is multidisciplinary by nature and requires highly sophisticated tools and deep expertise, often unavailable or unaffordable by individual research labs and businesses. The SDNI site will offer state-of-the-art knowhow, tools, and services of nanotechnologies to all interested users across the nation in a user friendly, timely, and cost effective manner. The site will also become a nanotechnology provider to create and develop new nanotechnologies and bring them to its users. The goals of the site are to serve a large number of academic, industrial, and government users, to transfer enabling nanotechnologies from research laboratories to the general user community, to educate and train future generations of scientists and engineers in nanotechnology, and to bring nanoscaled research experience to college students and K-12 students, especially underrepresented minority students, to prepare them for STEM careers.

The SDNI site will build upon the existing Nano3 user facility and leverage additional specialized resources and expertise at the University of California at San Diego. The SDNI site is committed to broadening and further diversifying its already substantial user base. The proposed strategic goals include: (i) providing infrastructure that enables transformative research and education through open, affordable access to the nanofabrication and nanocharacterization tools and an expert staff capable of working with users to adapt and develop new capabilities, with emphasis in the areas of NanoBioMedicine, NanoPhotonics, and NanoMagnetism; (ii) accelerating the translation of discoveries and new nanotechnologies to the marketplace; and (iii) coordinating with other NNCI sites to provide uninterrupted service and creative solutions to meet evolving user needs. Significant growth is anticipated in the number and variety of local and regional users in the academic, government, and industrial sectors. Discoveries made by users of the SDNI site have the potential to create transformative change in fields as diverse as medicine, information technology, transportation, homeland security, and environmental science, leading to improved healthcare, faster communications, safer transit, and cleaner water and air. To develop a more diverse and productive scientific workforce, the SDNI site will expand undergraduate and graduate training programs including REU opportunities to train 900 students over five years. Through an RET program and other activities, the site will work to increase the number of students from underrepresented minority groups who pursue studies and, ultimately, careers in STEM disciplines.

Precision tissue engineering is an emerging field that applies the principles of engineering and life sciences to the development of biological substitutes that restore, maintain or improve tissue function or a whole organ. The success of tissue engineering relies on the ability to manufacture/print complex, functional three-dimensional structures with seeded/encapsulated live cells. Current printing techniques are typically very slow, have limited printing resolution for cells, and are limited in their ability to fully replicate the in vivo environment, either in terms of the material used, the distribution of cells, or the complex geometries of the native physiology. These bioprinters are usually individual lab/fab based, not accessible to the broader scientific communities. This EArly-concept Grant for Exploratory Research (EAGER) award supports fundamental research to provide needed knowledge for the development of a cloud-based, rapid, 3D bioprinting platform that creates functional tissues with application to the emerging field of precision medicine. By using the anticipated system, a research team will be able to create specialized tools and share critical data with the biomedical science community through the cloud. Therefore, results from this research will benefit the U.S. economy and society. This research involves several disciplines including manufacturing, biomaterials science, cloud computing, and precision medicine. The multi-disciplinary approach will help broaden participation of underrepresented groups in research and positively impact engineering education.

This project presents a simple and rapid fabrication approach for encapsulating cells within complex 3D geometries using a combination of digital printing and a naturally-derived gelatin-based hydrogel. By providing scanless printing, the fabricated structures will not exhibit the planar artifacts induced by traditional drop-by-drop and layer-by-layer fabrication approaches that involve discrete movement of the linear stage to a new position. Such a bioprinting platform can create much better mechanical integrity of the tissue construct than a traditional bioplotter. The macromer solution used during fabrication can easily be changed to incorporate a variety of bioactive molecules, such as growth factors, drugs, or genetic cues along with multiple cell types. This work fills a large knowledge gap in the field for developing a scalable technique for rapidly fabricating complex 3D cell-laden scaffolds for precision medicine. The cloud-based software architecture will provide a modular, extensible, remotely accessible, and user-friendly "web app" to enhance the collaborative potential of the bioprinting platform across multiple users. The research team will perform experiments and simulation to understand the mechanism of light interactions with polymer chains, and establish relationships between process parameters and mechanical properties of the 3D-printed tissue scaffolds.

PROJECT SUMMARY Recent advances in rapid prototyping methods including stereolithography and nozzle-based bioprinting have enabled manufacturing of complex structures with controlled architectures and tunable properties. With their capability of patient-specific design and precision engineering, these technologies have impacted many areas such as tissue engineering and regenerative medicine. In tissue engineering, the fabrication of highly organized, functional three-dimensional (3D) constructs that mimic the complex architecture of various organs is of great importance. Towards this goal, different rapid prototyping strategies based on stereolithography and bioprinting have been demonstrated. Despite significant advances, however, the following key challenges for bioprinting biomimetic tissue constructs still remain: a) Current methods for fabricating 3D cell-laden constructs with clinically-relevant precision require time-scales that induce cell death. b) Multicomponent/multicellular tissue constructs with biologically-relevant architectures and characteristics are difficult or impossible to bioprint at present. To address both of these challenges simultaneously, we plan to develop a Rapid, Multimaterial Bioprinting (RMB) technology. The novel RMB approach is significantly faster than conventional 3D bioprinting and produces multicomponent complex architectures using diverse cell-laden biomaterials continuously. Therefore, this novel 3D bioprinting system can be used to build biomimetic tissues, such as pre-vascularized cardiac tissue with blood vessels ranging from larger anastomosable vessels to smaller capillaries. We will integrate a programmable microfluidic system with a dynamic optical printing method to deliver different cell types and gel precursors to mimic the biomechanical characteristics and compositions of the cardiac tissue. Specifically, we will incorporate iPS cell-derived human cardiomyocytes (iCMs) and endothelial cells (ECs) with designed spatial distributions in the engineered tissue constructs. We will then assess the maturation of the pre- vascularized cardiac tissues in vitro and examine the biocompatibility and functionality of the bioprinted vascular networks in a subcutaneous implantation model in nude rats. The completion of this work will be a paradigm shift and a landmark achievement in efforts towards clinical treatments of vascularized cardiac tissue.

Vascularization has been the bottleneck for engineering large-scale or highly metabolic tissues. Without vascular support, cellular viability and function of engineered tissues or organs will be compromised in very short time. Traditional biomanufacturing methods such as nozzle-based and ink-jet based 3D printing are often slow and have limited printing resolution for creating biomimetic vasculature. This EArly-concept Grant for Exploratory Research (EAGER) award supports fundamental research on a new biomanufacturing method that simultaneously offers the speed, the resolution, and the ability to process multiple biomaterials and cells to 3D print biomimetic vascular network. Results from this research will potentially transform the biomanufacturing field for future tissue and organ printing with biomimetic vascular network. Printing organs such as heart and liver will reduce the shortage of donor organs for transplantations and save lives. Additionally, the biomimetic in vitro tissue models could significantly benefit the pharmatheutical industry because they can be used in early drug screening for drug toxicity and efficacy testing.

The new biomanufacturing method features ultraviolet light-induced hydrogel formation in a scanningless and continuous fashion for rapid 3D printing of biomimetic vascular network. The first research objective is to understand the effects of material composition and processing parameters on mechanical properties of the hydrogel scaffolds for the 3D printing process. To achieve this objective, glycidal methacrylate-hyaluronic acid and gelatin methacrylate will be synthesized as the hydrogel materials with different methacrylation ratios. Hydrogel scaffolds will be printed by varying material composition (such as molecular weight and concentration of the monomers) and processing parameters (such as ultraviolet light intensity and exposure time). Mechanical properties (such as stiffness and yield strength) of printed hydrogel scaffolds will be measured by a nanoindentor and dynamic mechanical analyzer. The second objective is to understand how scaffold shape and chemistry affect vascular network formation. To achieve this objective, scaffolds of different shapes including single tubes and branched tubes will be printed using different hydrogels (glycidal methacrylate-hyaluronic acid and gelatin methacrylate). Human umbilical vein endothelial cells and mesenchymal stem cells will be encapsulated in the hydrogels to form a vascularized tissue. Vascular network formation such as lumens will be imaged using confocal microscopy.

Rapid 3D-printing of Multi-functional Adaptive Nerve Conduits The PIs propose to develop an innovative platform for the fabrication of 3-dimensional (3D) nerve conduits with precise spatial and temporal distribution of biological factors (growth factors, neuron stem cells and extracellular matrix (ECM)). This rapid 3D printing platform employs a dynamic mask for photopolymerization of an entire layer simultaneously without scanning and create 3D conduits continuously, resulting in 1,000 times faster in printing speed and 100 times better in printing resolution compared to traditional nozzle-based 3D printers. Hyaluronic acid (HA), an ECM component, will be modified for 3D printing. HA is a long-chain sugar-like molecule shown to be compatible with wound healing and nerve regeneration. Because it is naturally occurring in the body and has negligible inter-species variation, HA is an excellent candidate biomaterial to use for nerve conduits. Neuron stem cells and growth factors will be printed in the conduits to aid nerve repair. In the R21 phase, the PIs will develop the rapid 3D printing system, synthesize the HA materials and characterize the 3D printed HA conduits. The team will then implement these nerve conduits into mice to demonstrate growth of the nerve fibers along the bore of the conduit from proximal to distal end and also demonstrate reduction in time to functional recovery due to conduit-assisted growth and regeneration of the nerve fiber. Upon successful completion of these tasks and milestones in the R21 phase, subsequent work in the R33 phase will further develop the rapid 3D printing process to create designer nerve conduits with precise spatio-temporal control of physical, chemical, and biological properties and use such designer conduits for in vivo animal studies. The concepts and techniques developed herein would allow us to create precise, pre-designed distributions of growth factors and neuron stem cells with microscale resolution and enable us to investigate their effects on nerve cell guidance inside a conduit with complex architectures. The project will be carried out by a team of collaborative talents, including Dr. Chen who is a leading expert in 3D printing and a pioneer in bioprinting, and Dr. Nguyen who is a is board certified in both Head and Neck Surgery and Neurotology/Skull Base Surgery and is the Director of the Facial Nerve Clinic at UC San Diego. Dr. Nguyen has a clinical practice specializing in facial nerve paralysis and brings both clinical expertise as well as basic science research experience to this project.

Project Summary/Abstract Nearly 300,000 Americans have sustained some form of spinal cord injury (SCI), and effective therapies to promote recovery of neural function are lacking. Our overarching vision is to create an ex-vivo tissue that can replace the damaged spinal cord and enable formation of new relay circuits across sites of even severe injury. Our extensive rodent work with 3D printed biomimetic scaffolds shows that this approach can result in electrophysiological and functional recovery after complete spinal cord transection, the most severe model of spinal cord injury. This project aims to demonstrate the feasibility of scaling up a 3D printed biomimetic scaffold, loaded with human neural stem cells, to a clinically relevant, non-human primate model of spinal cord contusion. There are 3 objectives to this project: 1. Image the primate contusion-lesioned spinal cord by MRI scan. 2. Generate a 3D model and print individual scaffolds that conform to each subject's injury. 3. Implant 2 subjects with scaffolds: 1 Empty scaffold, 1 scaffold loaded with human neural stem cells. A demonstration of feasibility will lead to an R01 application in the non-human primate, with potential clinical translation.

Algae has been identified as one of the most promising sources of energy for biodiesel production. However, current algae cultivation techniques are inefficient and costly, which limits its scalability to meaningful production levels. In nature, coral reefs stand among the most productive ecosystems, powered by the high photosynthetic efficiency of the coral-algae symbiosis. But algae self-shading is currently a key limiting factor prohibiting expansion of commercial algae cultivation. The goal of this project is to investigate a novel manufacturing method to produce engineered corals with biomimetic light management strategies to cultivate living algae towards scalable algae-based biofuel manufacturing. If successful, this research will lay the foundation for rapid three-dimensional bioprinting of coral tissues. This work will define a new class of bionic materials capable of interacting with living organisms. The high spatial efficiency of the bionic coral system in three dimensions is particularly suitable for the design of compact bioreactors for algae growth in dense urban areas or as life support systems for space travel. Therefore, this research will have transformative impact to diverse sectors including advanced manufacturing and biofuel production, and directly impacts the economic welfare and national security of the United States. In education and outreach, the project will offer exciting interdisciplinary training that integrates contents from nanomaterials, biomaterials, to biomanufacturing. A diverse group of students, especially women and minority students at graduate, undergraduate, and K-12 levels will be trained in this project.

The research objective of the project is to understand how material composition and structure design affect the manufacture of the biomimetic coral construct and the proliferation of algae cells on the coral scaffold. To achieve this objective, a rapid 3D bioprinting method will be employed to manufacture optically-tunable scaffolds with nature inspired geometry to mimic coral tissue with microscale precision to cultivate algae. Analytical analysis will be carried out to simulate light propagation mechanism in the coral scaffolds. These simulation results will guide the design and 3D bioprinting process. Experiments will be conducted to study the mechanical, chemical, and biological properties of the biomimetic coral structure. This will be the first attempt in the field to use 3D bioprinting for algae biofuel manufacturing, therefore it will be high risk. But if successful, this work will transform the field of biofuel research and manufacturing. The PI is a pioneer in 3D bioprinting with an outstanding track record of research publications in the areas of 3D bioprinting, biomaterials, and nanophotonics. His laboratory and institution have excellent resources and facilities to support this work.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Since 2003, the Forum on Nanotechnology Forum between U.S. and Korea has been held at alternating countries. The forum focuses on enhancing research collaboration in the field of nanotechnology conversion among scientists and engineers from both countries. Specifically, a joint forum facilitates networking between the research communities and agencies of both countries, enabling each side to exchange information and explore opportunities for research collaboration. This year the topics are nanomedicine focusing on single-cell level and sensors related to human cognition and brain research. The forum includes 8 senior presenters and 7 early-career presenters from U.S. and roughly equal number of Korean presenters will also participate. Organizing committee of this forum strives to place emphasis on diversity. This forum actively encourages partnerships in nanotechnology for breakthroughs in various topics, in addition to strengthening achievements and assessing the progress on recommendation made during the previous forums. All of the forum proceedings and findings are available on Carnegie Mellon's website for broad audiences. The contribution of this proposed forum is its ability to bring together a bi-national community of expert researchers and innovators who are working on the leading edge of nanomedicine focusing on single cell level and sensors related to human cognition. This forum will stimulate efforts to promote the above two areas by fully utilizing nanotechnology convergence to bio-information-cognitive technology. The outcome of this forum will lead to milestone and vigorous research collaboration of both countries where nanotechnology convergence will generate a great impact.

As we enter the 4th industrial revolution, which is characterized by a fusion of technologies that is blurring the lines between the physical, digital, and biological spheres, the rapid increase in the enormous amount of data processed and stored led us to a need for an emerging field of technologies including human cognition and nanomedicine. To fully explore these technologies, nanotechnology convergence with bio-information-cognitive methods play a critical role. The following two topics will be scrutinized during this 16th Forum. (a) Nanomedicine focusing on single cell level: Current challenges in nanomedicine area involve i) long-term fate for newly developed materials (distribution in space and time) and how to integrate already-developed nano-materials into application synergistically, ii) the niche of nanomaterials, iii)changing the general paradigm of medical practice, iv) precisely monitoring patients for preventive medicine, v) personalized medicine, vi) batch-to-batch consistency validation, vii) need for safer biomaterial, and viii) ability to target moving parts. Due to the importance of single-cell nanomedicine, this topic will be examined during the consecutive forums. (B) Sensors related to human cognition and brain research: Key technical components of human performance modification (HPM) are the nanosensors. Novel nanosensors that are capable of new functions allowing an era in HPM will be investigated. This technology includes an image processing unit and an artificial intelligence unit to name a few. With added sensory inputs and augmented sensors, ultimately HPM can drastically enhance human performance on a daily basis. The convergence of nanotechnology is likely to result in the development of novel sensor technologies that can advance in HPM including vision, audition, gustation, olfaction, and somatosensation.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

While nanotechnology is revolutionizing many industry sectors and having significant impact to our daily lives, investigating the potential negative impacts of nanomaterials becomes ever more important. Most studies that focus on understanding potential health effects are carried out with cells cultured in a petri-dish. While such studies have provided a wealth of information about the importance of nanomaterial's physical, mechanical, and chemical properties in toxicity to cells, they inform less about the interactions of the nanoparticles with human tissues and organs. This project aims to create an engineered 3-dimensional human heart tissue model generated by a novel bioprinting technique, and to use this model to study the impact of nanoparticles on the heart. Success of this this project will eliminate the need for expensive animal model systems in studies of tissue and organ toxicity to nanomaterials. The highly interdisciplinary nature of the project will involve training students across the traditional boundaries, offering exciting topics including bioprinting, tissue engineering, nanotechnology, and biological interactions of nanoparticles. Also, the project will facilitate training broadly across multiple stages of professional and academic development by including graduate students, undergraduate students, and high school students of diverse backgrounds.

Technically, this project will be the first attempt in the field to investigate how nanoparticles interact with 3-dimensional human heart tissues, created by 3-dimensional bioprinting. The first research task aims to establish the bioprinted microscale human heart tissue model and evaluate cell alignment, morphology, gene expression, and cardiac function. The second research task will focus on the synthesis of a suite of monodispersed nanoparticles with varying compositions and surface coatings. Assessment of nano-cardio interactions will be carried out to investigate the effects of these nanoparticles on cell viability, morphology, gene expression, and cardiac force output. From this project, the feasibility of using these engineered human tissue models for nanotoxicity studies will be established. The project is of high-risk. But if successful, the outcomes of the project will lead to high reward since it will provide significant insights into the biocompatibility of nanoparticles to 3-dimensional human tissues. Using human induced pluripotent stem cells derived cardiomyocytes, the project will further reveal individual effects of these nanoparticles. The investigators are well situated and uniquely positioned to tackle these issues. The principal investigator is a pioneer in 3-dimensional bioprinting with an excellent track record for cutting-edge research in biomaterials, bioprinting, and tissue engineering. The co-principal investigator is a leading expert in studying the environmental and health implications of nanomaterials. Such a unique collaboration will lead to transformative results. The highly interdisciplinary nature of the project will enable student training across the traditional boundaries, offering exciting topics including biomanufacturing, nanotechnology and biological interactions of nanoparticles. Also, the project will facilitate training graduate students, undergraduate students, and high school students of diverse backgrounds.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Over 100,000 human diseases are caused by genetic alterations in the genome, and only a very small portion of these diseases can be cured. Gene editing represents a pivotal development in disease therapeutics as a powerful tool to correct defects and mutations within the genome. In particular, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Cas9 represents a paradigm shift in the ability to make precise, targeted genomic change. Recently, a few approaches have been developed for intracellular delivery of CRISPR/Cas9 complexes. While these approaches have some degree of success, it remains extremely challenging to achieve highly effective and efficient intracellular CRISPR/Cas9 delivery. This EArly-concept Grants for Exploratory Research (EAGER) grant supports research to design, manufacture, and test nanobots or nanoscale robots that can precisely target and deliver CRISPR/Cas9 to diseased cells and release the gene-editing agencies in a controlled fashion. The three-dimensional nanoscale printing method for fabricating the nanobots involves multi-materials printing and could be a powerful tool for scalable nanomanufacturing of functional nanoscale machines for a variety of applications. The nanobots could revolutionize gene or drug delivery to repair genetic disorder of many human diseases, which would have a strong impact on human health. The project offers exciting interdisciplinary training that integrates content from manufacturing to biomaterials to nanomachines to therapeutics for a diverse group of graduate and undergraduate students. Nanoscale printing and nanobots are excellent tools for laboratory demonstrations to attract high school students and teachers, and women and underrepresented minority researchers to science and engineering fields.

This project aims to investigate the nanomanufacturing processing of a novel nanobot system for targeted gene or drug delivery at the single cell level. The collaborative research team designs the nanobot using biocompatible materials and uses a nanoscale 3D printing system to fabricate it. The nanobot consists of a magnetic nanomotor and a biodegradable nano-cargo. The nanomotor, which is typically 200 nm round and 400 nm long, is 3D printed by embedding iron oxide magnetic nanoparticles in hydrogel. The nano-cargo, which is of similar dimensions, is also 3D printed by encapsulating CRISPR/Cas9 in a biodegradable hydrogel, so that CRISPR/Cas9 can be released through biodegradation once inside the cell. Fundamental research focuses on investigating the effects of material composition and properties, and nanomanufacturing processing parameters on the nanobot performance. The team also tests the efficacy of the nanobot to deliver CRISPR/Cas9 into cancer cells for tumor suppression. The scalability of the nanomanufacturing process is demonstrated through the reproducible fabrication of an array of nanobots.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

SUMMARY Vision loss in glaucoma and optic neuropathies results from the loss of retinal ganglion cells (RGCs) that is irreversible. Regardless of etiology, once cells are lost, RGCs cannot regrow and blindness is considered permanent. Retinas derived from pluripotent stem cells (PSCs) offer a source of tissue to address some of the mechanism(s) of human optic nerve cell loss at the level of the retina, however, one limitation to laboratory grown retinas is that they lack integration with higher order Lateral geniculate nucleus (LGN) and Superior colliculus (SC) neurons which ultimately connect with the visual cortex, thus they are not physiologic and retinal synapses might not form properly. As a first step towards understanding how to repopulate the eye with new RGCs and make those new connections, we propose to develop an optic nerve model to study axon outgrowth and pathfinding which will lead to improved engraftment of projections to the brain. Therefore, we propose to (1) develop a 3D printed scaffold that is permissive to axonal outgrowth, (2) improve the optic nerve by reconstructing the cellular components of the optic nerve, and (3) study cues to control proper connections through the optic chiasm. The optic chiasm represents the first relay station in the transmission of visual signals to the brain and thus is an important first step. We hypothesize that many developmental features of non- human mammalian models will also apply to developing human retinas. These features include neurite outgrowth and guidance towards the optic nerve head (stage I), axon guidance towards the optic chiasm (stage II), and decussation of ipsilateral and contra-lateral RGC axons [1-4]. We further hypothesize that human RGC axons emanating from PSC derived 3D organoids in hydrogel scaffolds will recapitulate these important features and thereby provide an experimentally tractable model for the study of glaucoma and other optic neuropathies. More importantly it will also provide a critical readout for testing therapeutic approaches aimed at restoring vision through cell replacement. We propose to develop a microprinted scaffold for 3D retinal organoids that will facilitate retinal ganglion cell (RGC) axon outgrowth and targeting and improve the organization of optic nerve cells and axon outgrowth by reconstructing the cellular components (including oligodendrocytes, astrocytes and microglial cells) of the human optic nerve.

Skeletal muscle has a unique capacity for repair after injury. This regenerative response fails in volumetric muscle loss injuries (VML), where a large volume of the muscle is damaged or removed, usually due to acute trauma. Current treatments for VML injury are limited, and often result in scar tissue formation and limited muscle function. Interest has been shown in developing myogenic scaffolds for VML repair. Clinical studies have investigated the use of decellularized extracellular matrix (dECM) laminated sheets derived from porcine bladder or small intestine submucosa (SIS) as acellular scaffolds for VML repair. ECM contains vital biologic factors (i.e. growth factors, basement membrane proteins, cryptic peptides) thought to be involved in the recruitment of progenitor cells, regulation of macrophage polarization, and tissue regeneration. VML injured muscles in animals and in humans implanted with dECM scaffolds have shown some muscle regeneration, including neovascularization and reinnervation in the scaffold, although the capacity of these muscles to generate force is still diminished compared to uninjured controls. Skeletal muscle exemplifies the structure- function relationship in biology; the capacity of a muscle to generate isometric force is directly related to the arrangement of fibers within a muscle. Histological examination of muscle in dECM scaffolds indicate poor fiber alignment with native muscle orientation, likely due to the lack of organized microstructure in the original dECM scaffolds, which is difficult to control using current fabrication techniques. We have developed a novel microscale continuous optical bioprinting (?COB) platform, which can be used to rapidly fabricate scaffolds with tissue informed microstructure and natural biomaterials (e.g. dECM) in 3D in a matter of seconds, providing a significant time and resolution advantage over traditional extrusion-based 3D printers. We broadly hypothesize that a scaffold consisting of dECM and an elastic, biocompatible material (acrylated poly (glycerol sebacate); PGSA) can promote organized muscle regeneration in a rat model of VML. In Aim 1, we propose to synthesize and fine-tune the formulation of PGSA, combined with dECM, to create an elastic, myogenic scaffold, with muscle informed microstructure using ?COB. In Aim 2, we will evaluate the capacity of the PGSA+dECM scaffold to regenerate skeletal muscle in a rat model of VML compared to tissue engineering solutions being explored in the clinic (laminated dECM sheets) at acute (2 weeks) and sub-acute (4 weeks) time points. 3D printing in healthcare represents the pinnacle for patient centric rehabilitation. This platform allows for physicians to design implants with any geometry, which can be directly extracted from standard presurgical imaging, to customize treatment for a patient. Future studies will evaluate the efficacy of this scaffold in larger animal models over longer time periods, with the long-term goal of clinical translation.

Summary Bioprinting plant virus nanoparticles for immunotherapy and relapse prevention of ovarian cancer High grade serous ovarian cancer (HGSOC) is the most common and severe form of ovarian cancer and women with HGSOC have a poor prognosis. Immunotherapy approaches that induce systemic antitumor immunity, in particular those that prevent relapse, are urgently needed for HGSOC. We propose to employ plant virus-like nanoparticles (VLPs) combined with slow release antigen depots as a cancer vaccine approach to launch sys- temic antitumor immunity during remission to block relapse. Our data indicate that intraperitoneal (IP) admin- istration of plant VLPs in a mouse model of ovarian cancer modulates the tumor microenvironment to relieve immunosuppression and generate adaptive anti-tumor immunity and memory against tumor antigens. The VLPs are non-infectious, non-cytotoxic, and non-cytolytic, but the highly repetitive nature of the proteinaceous VLPs triggers innate immune activation and associated adaptive immune response. Building on this, we will develop a VLP biopolymer formulation to enable effective immunotherapy following surgical debulking in HGSOC. We will incorporate irradiated tumor cells as source for patient specific tumor antigens; the cells will be delivered together with the VLPs which act as adjuvant to launch long-lasting anti-tumor immunity. The proposed immu- notherapy implant will be produced through an innovative 3D bioprinting technique; specifically, rapid, microscale continuous optical bioprinting (µCOB). This platform offers control over both the topographical complexity and the cellular and material composition of the scaffold at micron-level resolution. Our rapid 3D bioprinting process allows for photopolymerization of multiple biocompatible materials, and facilitates incorporation of VLPs and/or cells. The engineering design space and tunability of this approach is impeccable; in particular the implant will be designed so that therapeutic doses are released in programmed intervals (prime/boost) vs. continuous slow release. We will fulfill three specific aims: 1) Bioprint VLP biopolymer implants and test various configurations to optimize slow, continuous release vs. staged, e.g. weekly release of the therapeutic VLPs. The implants will undergo rigorous quality control and reproducibility testing and released VLPs will undergo structural analysis and biological testing. 2) Evaluate efficacy of the immunotherapy implants vs. soluble VLPs will be evaluated using mouse model of ovarian cancer (ID8vegf/defb29). Immunological investigation will provide insights into the mechanism of the immunotherapy. 3) To further explore vaccine parameters and model very low endogenous patient antigen loads during remission, we will bioprint biopolymer implants to deliver VLPs and antigen (from irradiated cells) prior to challenge with ID8vegf/defb29 cells. For future translational approaches, patient tumor from surgical debulking and/or patient neoantigen peptides would be used. The clinical significance is high: we envision a simple modification to the current treatment work-flow, where small degradable vaccine implants are left in the intraperitoneal (IP) cavity during surgery or administered subcutaneously (SC) post-surgery, or both.

As the interface between the maternal and fetal blood supplies, the placenta transports nutrients and oxygen to, and metabolic waste products and carbon dioxide away from, the fetus; it also produces hormones necessary for establishment and maintenance of pregnancy. To carry out these diverse functions, the placenta is comprised of functional units, called chorionic villi, which consist of loops of fetal capillaries surrounded by stromal cells, followed by cytotrophoblast, with the whole encased in a syncytiotrophoblast monolayer. As the placenta matures, the number of stromal cells and cytotrophoblast decrease significantly, resulting, at term, in an exchange interface composed primarily of fetal capillaries adjacent to the syncytiotrophoblast monolayer. Abnormalities in placental function are associated with common and clinically significant complications of pregnancy, including preeclampsia and fetal growth restriction. Given marked differences in placental structure and function between humans and experimentally tractable animal models, and the complex microarchitecture of the feto-maternal interface, there is a pressing need for in vitro models that can be used to experimentally probe the function of the human placenta. Traditional systems, such as choriocarcinoma cell lines, primary cytotrophoblast, placental explant cultures, and ex vivo perfusion of placental tissue, have significant limitations related to use of malignant cells to model non-malignant cells, failure to recreate the complex 3D relationships among different cell types, and/or short experimental life-span. Recently, placenta-on-a-chip approaches have been applied, but existing implementations lack the ability to recapitulate the native microenvironment, anatomical structure, and long-term function needed for detailed mechanistic studies. We will address these challenges by engineering a novel human placenta-on-a-chip in a microfluidic platform, which will recapitulate human placental microstructure and function. By using a rapid 3D bioprinting method, we are able to better replicate the intricate microarchitecture of the native maternal-fetal placental interface at term and incorporate each of the key human placental cell types, including placental microvascular endothelial cells, and primary cytotrophoblast or human trophoblast stem cells. The work will be accomplished in two aims by: (1) building the 3D placenta-on-a-chip and confirming the spatial placement, viability, and identity of the component cell types, and (2) performing detailed evaluation of our platform as a biomimetic model of placental function, including assessment of barrier formation, and the effects of varying glucose concentration and oxygen tension on biomolecular transport, production of placental hormones, and intracellular and extracellular RNA expression. Where appropriate, these results will be compared to those obtained from placental explants cultured in the same conditions. This work will produce a validated novel 3D bioprinted placental model that can be used to reveal the mechanisms of placental function and dysfunction in normal and complicated pregnancies.