Yong Xu, Ph.D. - US grants

This integrative systems proposal focuses on the development of a novel intelligent textile technology and its application for continuous respiratory sound monitoring. To overcome the conflict between the flexibility of the textiles and the rigidity of the sensing and computation components, a novel approach is proposed by integrating textiles with flexible transducers/circuits that are fabricated with a unique 'flexible-skin' technology. The uniqueness is that the flexible skins are fabricated based on silicon wafers. Various MEMS devices and circuits can be fabricated on silicon wafers first using existing technologies, then be made flexible, and finally be woven into textiles. Therefore, the existing mature technologies can be directly borrowed and significant R&D efforts can be saved by avoiding re-invention. The proposed research will lead to intelligent textiles, which are as flexible and comfortable as the regular fabrics and able to perform a vast variety of functions, for the first time. The proposed intelligent textiles will serve as a generic platform for various integrative systems and open the door to numerous new applications. Simultaneously, the research will be effectively integrated with education through a new education program in intelligent textiles. Special programs will be developed for high school students and undergraduate students. As evidence of the broader impact of the proposed activities, efforts will be made to include the participation of underrepresented groups. The proposed research also has the potential to establish a new technology-intensive industry that helps to create new job opportunities inside the United States.

Intellectual merit: The goal of the proposed research is to develop a nonlinear nanoprobe for nano-femto scale spatiotemporal characterization of ultrafast optical near fields. The proposed nanoprobe consists of a nonlinear nanoparticle attached to a nanowire, which is in turn attached to a silica fiber taper. The nonlinearity of the nanoparticle enables temporal characterization through autocorrelation or frequency resolved optical gating measurements while the nanoscale spatial resolution is achieved through near field scanning of the nonlinear nanoparticle. We will develop two-photon fluorescent and second harmonic nanoprobes, develop and optimize nanoprobe based spatiotemporal characterization technique, and investigate the precision of the proposed nanoprobe based method. With the unique capabilities of the proposed nonlinear nanoprobes, we also plan to investigate their applications to probing several interesting ultrafast optical near fields.

Broad impact: The proposed nanoprobe can significantly advance the state of the art of nano & ultrafast technology, which can in turn create far-reaching impacts in many scientific disciplines in which they play a central role. With its unique capability in providing nano-femto scale spatiotemporal mappings, the proposed nonlinear nanoprobe can find many important applications. Fundamental questions with regard to light-matter interaction in the ultrafast regime, ultrafast dynamics of complex nanostructures, and nonlinear optics in nanoscale plasmonic structures, can all benefit from the development of the proposed nanoprobe. As a result, the proposed research can have considerable impact on areas such as nonlinear optical microscopy and nanophotonics. The proposed research is highly interdisciplinary and can also provide excellent education opportunities for students.

0922912
Coleman
Wayne State U.

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."

Technical Summary: A scanning electron microscope (SEM) is a very important instrument for research in Materials Science and related fields. Nanotechnology efforts at Wayne State University (WSU), a nationally ranked Research University, includes emphasis in the following areas: (i) nanoparticle synthesis and assembly; (ii) direct self-assembly of nano-crystalline and thin films; (iii) sensors and nano-devices, biosensors; (iv) drug delivery; and (v) energy materials such as solar energy materials and catalysts for fuel cell technology. The proposed (Field Emission) FE SEM is required to achieve the required resolution (1.4 nM), as well as imaging of conductive and non-conductive materials and biological samples in all these areas. These capabilities are not possible with the existing 20+ year old technologically-out-of-date instrument. The instrument will be located in the WSU Laboratory of Analytical Electron Microscopy (LAEM) that is one of several core facilities administrated by the Central Instrument Facility (CIF). The instrument will be available to the entire WSU campus, other local universities, and local industries. This instrument will impact more than 100 users from 25 research groups across the WSU campus, 3 groups from University of Toledo, and several local companies. This instrument will also affect the education quality for undergraduate and graduate students majoring in Materials Science, Physics, Chemistry & Chemical Engineering, Electrical and Computer Engineering and Biological Science. This instrument will explicitly be used by a large number of graduate students and post-doctoral fellows as part of their on-going research experience and maturation.

Layman Summary: A scanning electron microscope (SEM) is a very important instrument for research in Materials Science and related fields. It is used not only for imaging the surface of samples as a magnifier with higher resolution than possible with optical microscopes, but also for obtaining information about the local chemical composition and crystal structure by using various specialty detectors. Nanotechnology efforts at Wayne State University (WSU), a nationally ranked Research University, includes an emphasis in several area including: nanoparticles, thin films for semiconductors, biosensors for disease detection; drug delivery for medical patients, solar energy materials, and fuel cell technology materials. The proposed (?Field Emission?) FE SEM is a state-of-the-art instrument that is required to achieve maximum magnification on conducting and non-conducting materials and biological samples. None of this is possible with the existing 20+ year old technologically out-of-date instrument. The instrument will be located in the Laboratory of Analytical Electron Microscopy (LAEM) at WSU that is one of several core facilities administrated by the Central Instrument Facility (CIF). The instrument will be available to the entire WSU campus, other local universities, and local industries. This instrument will impact more than 100 users from 25 research groups across the WSU campus, 3 groups from University of Toledo, and several local companies. This instrument will also affect the education quality for undergraduate and graduate students majoring in Materials Science, Physics, Chemistry & Chemical Engineering, Electrical and Computer Engineering and Biological science. This instrument will explicitly be used by a large number of graduate students and post-doctoral fellows as part of their on-going research experience and maturation.

Abstract
Research objectives and approaches: The objective of this research is to develop next generation 3-dimensional (3D) neural probes with combined electrical and chemical interfaces. The approach of the proposed neural probe technology is based on a flexible skin technology and a simple folding process.

Intellectual merit: The proposed technology simplifies the fabrication and assembly process of high density 3D arrays of electrodes. Furthermore, this technology enables integration of microchannels with 3D neural probes. These channels, together with electrodes, enable combined electrical and chemical stimulation, thus opening the door to many important new applications. Local drug delivery at the implantation site by microchannels would be a promising approach to reduce/suppress tissue response, one of the major obstacles for successful chronic implantation.

Broader impacts: The proposed neural probes are expected to make a significant impact on treatment of many neural disorders such as paralysis, refractory epilepsy, Parkinson?s disease, Alzheimer?s disease, blindness, deafness, and tinnitus. These probes will also help us to better understand the operation of the brain, as a result of the 3D spatial resolution and multi-modal stimulating/sensing capability. The new methods and findings will be incorporated into a Micro/Nano-Electro-Mechanical Systems course developed by Prof. Xu. A unique component of the education plan is the training of an MD/Ph.D student. This team is committed to broaden the participation of underrepresented groups, evidenced by the PI?s active role in the Research Apprentice Program for Minority Students in Detroit Public Schools.

The objective of this research is acquisition of a dual beam focus ion beam (FIB) system, which will permit synergistic opportunities for nanotechnology, biomedical and energy research at Wayne State University (WSU). The approach is to use the FIB system as a central tool for several current and future projects, which urgently demand the ability to fabricate novel three-dimensional nanostructures and nanodevices in situ. This is a capability uniquely offered by FIB.

Intellect Merit: The sub-100 nm resolution three-dimensional patterning capabilities of FIB through milling/deposition will facilitate many research projects that require custom fabricated complex nanostructures and nanosystems. Consequently, FIB will significantly improve the quality and creativity of research at WSU in a broad range of areas from the development of devices and instrumentation (AFM, NSOM, scanning probe) to biomedical applications (biophysics, DNA sequencing, nanofluidics, single cell analysis, imaging, biosensor) to energy research (characterization of battery materials, catalyst and nanomaterials).

Broader Impact: The success of this proposal will significantly enhance WSU capabilities for nanofabrication and material characterization. FIB will be available to the entire WSU campus, other universities and local industry. Together, we estimate that this proposed FIB will impact more than 100 users from 20 research groups. For local industry, it will serve as a resource for advanced manufacturing, product prototyping and material characterization. This proposal represents a unique opportunity for training under-represented groups, which comprise 41% of WSU?s enrollment. The PIs will integrate FIB in their on-going projects and FIB in training of students.

This NUE in Engineering program entitled, "NUE: Development of an Undergraduate Certificate Program in Nanoengineering for Training the Workforce of Tomorrow", at Wayne State University (WSU), under the direction of Dr. Guangzhao Mao, will create a Nanoengineering Undergraduate Certificate Program (NUCP) that will target current engineering students as well as B.Sc. degree holders who wish to expand their educational background. Rather than creating a new degree program, the NUCP will offer accelerated and in-depth training on nanotechnology at the undergraduate level in the form of a certificate program. The Program seeks to meet the demands of Michigan's largely manufacturing economy and also the high-tech industries currently settling in the state. The NUCP seeks partnerships with major Michigan companies as well as start-ups in the Detroit Tech Town area to create an engineering curriculum that meets industrial demands. To that end the project team has established partnerships with BASF and DTE Energy. The primary objective of the proposal is to create the NUCP for specialized undergraduate training in nanotechology. Other objectives are: 1) to teach emerging technologies at the undergraduate level, 2) to train a new adaptive workforce, and 3) to retrain working engineers and professionals. In order to achieve these objectives, a certificate program consisting of four new courses will be created: 1) NE5300 Introduction to Nanotechnology and Nanomedicine, 2) NE5100 Nanoengineering Laboratory, 3) NE5200 Scale-down Engineering: from Engineered Sysems to Nanotechnology, and 4) NE5300 Nanoengineering Reesaerch and Capstone Design. The courses will be taught by faculty members from different engineering departments with emphasis on integration of teaching and research, as well as cross-disciplinary teaching. In addition, the engineering faculty will collaborate with faculty from political science and economics at WSU to conduct program evaluation.

The NUCP will provide a mechanism for undergraduate students, many with diverse backgrounds, to acquire specific knowledge and skills in nanoengineering beyond their traditional disciplinary training. The expected impacts on the undergraduate curriculum are as follows: 1) Courses offering multidisciplinary training in nanoengineering will be created and integrated into one certificate program. 2) Existing research infrastructure will be used in undergraduate education. 3) Undergraduate students will obtain research-level career training. 4) Retraining will be offered to working engineers, enabling them to advance their careers in Michigan and elsewhere. The NUCP will: 1) prepare the future workforce for careers in emerging technologies, 2) focus on relevance to systems and devices, and 3) invigorate undergraduate engineering education by developing new teaching modules that cross traditional departmental and disciplinary boundaries.

In optical fibers, sensing is traditionally carried out using a single mode operation, technically denoted as Single Mode Fibers (SMF). This operation greatly reduces the complexity of sensor signal processing, but at the same time, significantly limits the capabilities of fiber sensors and sensing systems. In this project, adaptive optics methodologies are employed in conjunction with mode division multiplexing techniques to greatly expand the overall sensing capacity of fiber optics sensor networks and to reduce their per-sensor-cost by a factor of 10 to 100. The novel mode division multiplexing, or MDM, sensing technology investigated in this project can impact a wide array of critical sensing applications and data communication, and will enable large-scale low-cost infrastructure monitoring as well as flexible and ultra-high-data-rate internet communications.

Technically, this project aims to develop a first-of-its-kind MDM sensor network for distributed sensing. The most critical element of this sensor network is an adaptive optical component that can: 1) achieve highly selective mode excitation in a multi mode fiber, and 2) dynamically route the interrogation signals towards different sensor sub-networks. Specifically, two multi modal sensor networks will be demonstrated: a quasi-distributed one for temperature/strain sensing, and a fully distributed one for optical time-domain reflectometry sensing. The goal is to demonstrate that it is possible to integrate multiple effective sensors in a single fiber by exploiting the multi mode operation. A secondary goal is to confirm the full compatibility of mode division multiplexing with state-of-the-art multiplexing methods. Accomplishing these two goals will suggest that by employing fiber modes utilizing M modes, one can increase the overall sensing capacity of any existing fiber sensor network by a factor of M. While the project will be limited to two-mode operation (M=2), which will lead to the doubling of the sensors density available on a given fiber, it is fully expected that the developed principles will be applicable to cases with M as large as 10 to 100, corresponding to ten-fold or hundred-fold increase in sensor densities.

CBET 1438112

This project aims to develop a new method to measure the fluid properties of tiny liquid droplets by using light to deform the shape of the drop. The method involves using a laser and an optical fiber to inject photons into the drop. These photons form a whispering gallery mode, which is an optical wave that is reflected by the droplet interface and circulates near the equator of the drop. The radiation pressure from the optical wave causes the interface to bulge, which, in turn, causes a change in the frequency of the whispering gallery mode. By detecting the change in frequency, extraordinarily small changes in the shape of the drop can be measured. These shape changes can then be used to deduce the surface tension of the fluid interface and the viscosity of the internal fluid. There are no other comparable methods for measuring these properties in micron-size drops. Thus, the project will provide scientists and engineers with a new tool for measuring physical properties that can be applied to colloidal systems, emulsions, aerosols and other suspensions that are formed in many manufacturing processes and biological systems.

The presence of high-Q whispering gallery modes within the liquid drops will be established through optical spectrum measurements. The optical force that induces drop deformation will be experimentally confirmed and characterized. Drop deformation will be determined by measuring shifts in the whispering gallery mode resonance frequency. Results will be verified by measuring deformation with white light interferometry that is capable of detecting interface movement with nanometer scale resolution. The roles of surface tension and viscosity will be investigated by comparing the measured drop deformation and rate of deformation with boundary element solutions of the Stokes equations for the drops. Experiments will be carried out using simple fluids such as water and silicone oils. A system consisting of nanoparticles suspended in liquid will be characterized to simulate whispering gallery mode induced drop deformation in a more complex fluid.

Multi-location gas sensing is critical for a large number of civil infrastructure and environmental applications, including energy grid monitoring and the surveillance of dangerous processes such as carbon sequestration or areas such as coal mines and landfills. For such applications, which generally involve a harsh sensing environment with significant safety concerns, fiber optic gas sensing is often the only solution. This is because fiber gas sensors consume little energy and have no need for batteries or other potentially "unsafe" electrical power supplies. Traditionally, it has been difficult to combine a large number of fiber gas sensors together for multi-location sensing. This project aims to overcome this challenge by developing an adaptive gas sensor network, where the behavior of each gas sensor can be individually tuned by changing the spatial profiles of optical signals within the sensor network. This makes large scale integration of 10 to 100 gas sensors possible. As a result, this project has the potential to significantly reduce per-sensor-cost for gas sensing and impact a myriad of engineering applications that involve explosive or dangerous gases. This project also includes a comprehensive education and outreach plan targeting underrepresented groups at all levels.

Current approaches for fiber optic gas sensing rely on using single mode fibers. This project aims to overturn this conventional paradigm, and to demonstrate a first-of-its-kind adaptive mode-division-multiplexing (MDM) gas sensor network based on few mode fibers. In this approach, the sensing characteristics of individual gas sensors can be dynamically modulated by using adaptive optics (AO) to control the mode composition of interrogation signals. This sensor network relies on the highest order fiber mode for gas detection and utilizes the lowest order fiber mode for low loss signal transmission. This unique design allows one to resolve the fundamental conflict between high gas sensitivity, which requires large gas attenuation for individual sensors, and large scale multiplexing, which demands low-loss power transmission for the entire sensor network. Specifically, this project aims to experimentally demonstrate an AO-MDM sensor network that contains at least 10 gas sensors for acetylene monitoring, and theoretically explore the possibility of constructing a highly multiplexed sensor network with 100 or even 1000 gas sensors.

Obesity is a major risk factor for type II diabetes and metabolic syndromes. Increased understanding of body weight regulation may lead to effective strategies to combat obesity and diabetes. Hypothalamic neurons, including anorexigenic pro-opiomelanocortin (POMC) neurons and orexigenic Agouti-related peptide (AgRP) neurons, integrate multiple metabolic cues (e.g. leptin and insulin) to provide a coordinated control of energy and glucose homeostasis. We found that an adaptor protein, growth factor receptor-bound protein 10 (Grb10), is abundantly expressed in the hypothalamus, and its expression is elevated by HFD feeding. Further, Grb10 inhibits both leptin and insulin actions in neurons. Importantly, deletion of Grb10 in hypothalamic neurons leads to profound lean phenotypes in mice. Based on these, we hypothesized that Grb10 promotes body weight gain by negative regulation of leptin and insulin signaling in hypothalamic neurons. The first objective will focus on anorexigenic POMC neurons. We will generate two opposite genetic mouse models: one with Grb10 deleted in mature POMC neurons and the other with Grb10 overexpressed in mature POMC neurons. We will use these loss- and gain-of-function models to determine how Grb10 in POMC neurons regulates energy and glucose balance, modulates leptin and/or insulin signaling pathways, and controls firing activities and gene expression. The second objective will focus on orexigenic AgRP neurons. We will use the similar approaches to delete or overexpress Grb10 in mature AgRP neurons. We will use these loss- and gain-of-function models to determine the physiological role of Grb10 in AgRP neurons in the regulation of energy/glucose balance. Further, we will explore the cellular and molecular mechanisms by which Grb10 modulates leptin/insulin-induced signaling pathways and regulates firing activity and gene transcription of AgRP neurons. The third objective is to use in vitro approaches to determine the molecular mechanisms for Grb10 to inhibit leptin signaling. To this end, we will first map the interacting regions between Grb10 and the leptin receptor molecules, and then determine if such interaction provides a mechanism for Grb10 to inhibit leptin signaling. These studies could lead to important advances in our understandings regarding the central regulation of energy/glucose homeostasis. We may also provide mechanistic insights on the fundamental biology for leptin/insulin signaling in the brain. Finally, the proposed studies may carry translational impact on human health, as we may identify brain Grb10 as a rational target for potential anti-obesity therapy.

The Arctic tundra contains a large amount of soil organic matter (SOM), and approximately half of Earth's SOM is associated with permafrost in high-latitude ecosystems. Arctic SOM has been undergoing thawing and accelerated microbial degradation as temperatures increase, producing large amounts of active organic carbon and greenhouse gases (e.g., carbon dioxide and methane). It is vital to measure current levels of these gas emissions from the tundra accurately, as a baseline for future measurements and for more accurate modeling of likely effects from the increased warming of Arctic SOM. However, the Arctic tundra is a complicated multi-phase system, and soil temperatures may stay below freezing for eight months or more every year, making the detection of soil gas emissions extremely difficult under field conditions. Current sensor technologies are inadequate for making accurate measurements of greenhouse gases in Arctic soils. This project will develop a low-cost, low-power multimodal sensor that can provide spatially and temporally expansive, continuous in situ measurements of dynamic changes of soil carbon dioxide and methane across the Arctic over time. The envisioned sensor will be small, inexpensive, and will need little power for operation. It can be deployed across wide areas to obtain soil gas data in natural conditions and will enable near-real-time reporting of field measurement data year-round. Data from these sensors will help advance knowledge in several disciplines, such as understanding the influence of permafrost warming on Arctic soil carbon release, and the fundamental biogeochemical or carbon cycling processes in the Arctic ecosystem. That new knowledge will help facilitate the development of new ways of managing soils and natural resources in cold environments.

This project will be carried out by an established interdisciplinary team with complementary expertise to develop the new sensor technology to address challenges in Arctic soil gas analysis. The key innovation is the use of ionic liquids (ILs) as a selective solvent and electrolyte for the development of miniaturized multimodal electrochemical and piezoelectric quartz crystal microbalance (E-QCM) sensors to measure soil gases in situ. ILs possess unique solvent and electrolyte properties that make them suitable for use under Arctic conditions where conventional sensing materials would be subject to both physical and chemical changes. The project will (1) Develop a multimodal E-QCM sensor and sensor array for methane and carbon dioxide detection under Arctic conditions; (2) Characterize and validate these sensor arrays using synthetic Arctic soils with known composition; and (3) Develop a rugged sensor package for in situ field tests in natural Arctic soils. The new sensors are expected to operate under Arctic conditions, simultaneously monitoring both electrochemical and piezoelectric signals of soil methane and carbon dioxide with the redundancy, sensitivity, and selectivity required for in situ measurement of soil gases in Arctic tundra.

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.