Jonathan D. Posner - US grants

CBET-0747917
Posner

Colloidal crystal films (CCF) are being developed as photonic crystals for integrated optical circuits, as super hydrophobic surfaces, and as solid-state sieving matrices for biochemical separations. Colloidal crystal films are comprised of 20 or more layers of face center cubic packed nanospheres (20-500 nm). These films are typically deposited by a fluid self-assembly process of a non-dilute colloidal suspension of nanoscale spheres. Current CCFs are plagued with unwanted defects in the range of 20-1000 sphere diameters that limit device applications. Solvent evaporation and electrophoretic deposition methods are largely developed by trial and error and suffer from a lack of fundamental understanding of the governing physics. The ability to control colloidal crystal film structure and reduce film defects is limited by the complex role of the fluid transport on the deposition process. These flows include the coupling of free surfaces and electric fields with high volume fraction suspensions and locally varying viscosity, density, surface tension, conductivity, and permittivity. They are time-dependent, three-dimensional and exhibit a wide range of time and length scales that make them difficult to model and observe. This research investigates the transport physics of colloidal crystal film deposition where high volume fraction colloidal suspensions flow with free surfaces and electric fields. A high-speed, spinning disk confocal microscope will be developed to measure the three velocity components and crystal structure in real-time and real-space. This research will enable depositions of defect-free colloidal crystal films and structures for a host of emerging technologies. The high speed confocal system will impact a wide range of disciplines including microfluidics, rheology, colloidal science, and real-time cellular imaging. Fundamental understanding of colloidal crystallization can be applied to molecular crystallization such as protein crystallography. This program integrates research with mentoring, education and outreach impacting students from middle school through graduate school. The study includes the development of a middle school outreach program ?got flow?? for underrepresented middle school students in the Phoenix metropolitan area. The ?got flow?? program has three phases: outreach modules directly inspiring 1000 8th graders to study math, science, or engineering; RET to provide research experience and state mandated professional training for middle school teachers; and educational transfer modules (ETM) that convey the modules to individual middle schools. The PI will expand undergraduate research opportunities for Hispanic and Native Americans who have relatively high enrollment at ASU, but low representation in engineering nationwide.

0853379/0853375
Posner, J./Wang, J.

Synthetic nanoscale motors represent a major step towards the development of practical nanomachines. Despite impressive progress, manmade nanomachines lack the efficiency and versatility of their biological counterparts. Extending the scope of synthetic nanomotors to diverse and realistic conditions requires deep understanding of their fundamental physical mechanisms. This proposed collaborative research aims at gaining such understanding of the underlying physical mechanisms of catalytic nanowire motors. The intellectual merit of the proposed work is to extend the fundamental understanding of the nanomotors propulsion, through a parallel experimental and theoretical approach, to guide the rationale design of powerful and versatile manmade nanomachines that can perform demanding tasks. The three main aims of the proposed work are: (1) understand physical mechanisms that govern the motion and performance of nanomotors using novel experiments and theoretical models (2) Identify and optimize nanowire properties (catalysts composition and morphology, wire shape, and surface coatings) that yield order of magnitude faster and more powerful nanomotors. (3) Fabricate nanomotors capable of operating in a wide range of environments (pH, ionic strength) and fuels (e.g. glucose, ethanol), enabling ranging operation in a variety of applications and demanding tasks such as directed drug delivery, directed nanoscale self-assembly, chemotactic environmental remediation, or microchip bioassays.

This research is transformative in that the improved understanding of the fundamental catalytic nanomotor physics will lead to powerful motors that are stable over long periods for performing complex tasks in a wide variety of environments and applications. To ensure success of the interdisciplinary research program, the team is comprised of two co-PIs with complementary experience. The proposed effort requires expertise in catalysis and electrochemistry (Wang), nanowire fabrication (Wang), low Reynolds number hydrodynamics (Posner), microscale diagnostics (Posner), electrokinetics and electrostatics (Posner). The PIs' extensive preliminary data, broad and complementary experience and past collaboration lay the groundwork for the success of the proposed activity.

The proposed effort will have broader impacts by integrating research with training, education, mentoring, and social outcomes. Particular emphasis will be given to the involvement of Hispanic students at the undergraduate and graduate research levels. They leverage the uniqueness of their locations by expanding undergraduate research opportunities for Hispanic students which have relatively high enrollment at ASU and UCSD, but low representation in engineering nationwide. This grant will provide distinctive experiences for undergraduate and graduate students to appreciate and participate in how their research on nanotechnology may transform society and to examine science and technology policy. In particular, they will develop a nanomachines course for a emerging nanotechnology curriculum in a new UCSD department of Nanoengineering. In addition, at ASU they aim to increase engineering graduate students' awareness of the societal and ethical implications of nanoscience and technology. In collaboration with faculty in the NSF Center for Nanotechnology in Society they will (1) develop a cross-listed, co-taught graduate level course entitled Societal and Ethical Implications of Scientific Research focusing on nanotechnologies; and (2) ASU and UCSD students will participate in a two week workshop in Washington, DC entitled "Science Outside the Lab: A Policy Dis-Orientation" which examines scientific policy and culture.

0932885
Posner

Over the past five years, there has been a growing interest in the health-related issue of toxicity of engineered nanomaterials. Cells have various routes for uptake of molecules and particles through their cell membranes to control their internal environment including highly selective membrane proteins and peptides as well as protein mediated endocytosis and phagocytosis. Nano-particle (NP) based drug delivery and molecular imaging applications that deliver NP into cells typically use biochemical functionalization which promote specific signaling and uptake. The lipid bilayers that make up cellular membranes are believed to be impenetrable to ions and unfunctionalized macromolecules, however, epidemiological studies have shown that unfunctionalized NPs can, under some conditions, cross or disrupt the cell membrane through passive, unmediated routes causing acute cellular toxicity and cell death. The unmediated NP adsorption onto and the uptake into cells is poorly understood. Recent research focuses on either collection of empirical epidemiological data (e.g. uptake of NP by cells, toxicity to organisms such as rats or fish) or precise NP characterization (e.g. size, shape, degree of aggregation, charge, and surface chemistry). However, it is almost impossible to transition from these measurements to detailed understanding of the mechanisms responsible for unmediated NP uptake into cells and disruption of the bilayer. Quantitative measures of nanomaterial bioavailability and toxicity need to be assessed so that the impact of nanotechnology on human health and the environment can be addressed.

Intellectual Merit: The intellectual merit of the proposed work is to understand the mechanisms and conditions under which engineered nanomaterials can cause disruption of, and passive transport through, simplified model cell membranes, namely lipid bilayers. The,investigators hypothesize that under some conditions engineered NPs can passively translocate across, and cause nanoscale defects in, bilayers which plays a role in cellular toxicity. The interaction of nanoparticles and lipid bilayers are unique because the particle and membranes have nearly the same length scale.

Broader impact: Fundamental understanding of the interaction between NP and lipid bilayers is potentially transformative because it may: (1) improve our understanding of toxicity of engineered and environmental NP; (2) enable rational design of benign NP for delivery of drugs and biomedical/molecular imaging; (3) result in high-throughput toxicity testing protocols; and (4) evidence-based regulation and protocols of nanomaterials. An experimental platform and methods will be developed for quantifying the NP transport through lipid membranes in real time as a function of the NP and lipid properties and the physicochemical environment. A "bottom-up" approach will be employed to increase the complexity of the bilayer through incorporation of membrane proteins as well as glycolipids to form an artificial glycocalyx.

Engineered nanoparticles are largely unregulated because the transport, fate, and toxicity of NP have not been adequately assessed. The proposed research focuses on the interactions of engineered nanomaterials with lipid bilayers, arguably the most important interface between life and the environment. This proposal addresses NP toxicity and has strong implications on the regulation of NP production, distribution, and application in medicine, clothing, cosmetics, etc. As an integral part of the proposed work, the PI aims to increase engineering and physical science graduate students' awareness of the societal and ethical implications of nano science and technology through: (1) development of a cross-listed graduate level course on the societal and ethical implications of nanotechnology; and (2) organization of a two week student workshop in Washington, DC which examines scientific policy and culture. The PI will also build upon his strong commitment to undergraduate research by funding underrepresented undergraduate researchers.

PI: Santos, Veronica J. and Posner, Jonathan D.
Proposal Number: 1264444 & 1264046

Intellectual Merit: Whether a prosthetic hand is a simple body-powered hook or an advanced anthropomorphic device, it will only be useful and desirable to an amputee if it improves quality of life and is intuitive to control. A prosthesis will be rejected if it poses too great of a cognitive burden on the user. One way to simultaneously reduce the cognitive burden on the user and enhance the functionality of the user to focus on high-level commands as opposed to low-level details that may be frustrating to control or even impossible to control given the "language barrier" between human and machine because of different timescales and resolutions of control. Amputees could be empowered with prostheses having autonomous, local reflex algorithms akin to short latency grip reflexes observed in humans, and even suites of basic behavioral building blocks that are critical for activities of daily living. The only way for a semi-autonomous system to gain the trust of its operator is through reliable, context-dependent performance. Such context-aware performance will require information about forceful interactions between the prosthetic hand and everyday objects in unstructured environments that can only be obtained through touch. The great number and dynamic range of tactile mechanoreceptors in the human hand (17000 tactile sensors total, 2000 in each fingertip) highlight the importance of rich multimodal tactile feedback for grasp and dexterous manipulation. Unfortunately, many tactile sensor designs have focused on detection of normal forces alone, which are necessary but not sufficient for reliable artificial grasp. What is sorely needed is a multimodal tactile sensor that can detect additional important features of finger-object interactions such as shear force, vibration, and slip direction. This proposal aims to strengthen the ability of an artificial hand to perform automated behaviors reliably by detecting, processing, and utilizing rich, real-time information about finger-object interactions with an innovative multimodal tactile sensor skin. This sensor system is transformative because it will reduce the cognitive burden on an amputee and will provide a foundation for paradigm-shifting advancements for automating complex behaviors by artificial hands and providing a conscious perception of touch through sensory feedback to the user. The long-term research objective of this proposal is to reduce the cognitive burden on the user of an upper extremity prosthesis. The following contributions to artificial hand systems are proposed: Research Goal 1) Design, model, fabricate, and test a flexible, multimodal tactile sensor skin system for artificial fingertips using a multilayer microfluidic architecture; Research Goal 2) Establish functional relationships between finger-object interactions and tactile sensor skin data for use in autonomous grip control algorithms; and Research Goal 3) Integrate the tactile sensor skin data into grip control algorithms and evaluate effectiveness for reducing the cognitive burden on prosthesis users.

Broader Impacts: The proposed translational research could enhance the functional capabilities of artificial, robotic manipulators intended for unstructured, unsafe, or limited-access environments (prosthetic, rehabilitative, assistive, space, underwater, military, rescue, surgery). The proposed work could play a critical role in improving the quality of life for end-users of prosthetic and assistive devices. Specific benefits to end-users of prosthetic devices include: automation of complex prosthesis behaviors, rich artificial sensory feedback, and "smart socket liners" for monitoring user safety and comfort.

Contributions to elementary school, undergraduate, and graduate-level education are proposed: Education Goal 1) Develop hands-on instructional modules for teaching elementary school students about sensors using low-cost materials, and deploy them locally for the benefit of students underrepresented in science, technology, engineering, and mathematics fields; Education Goal 2) Enhance undergraduate-level course titled Sensors and Controls and graduate-level course titled "Robotics" with a sensors module; and Education Goal 3) Promote interdisciplinary undergraduate research opportunities via internships related to the development, testing, and application of sensors.

The main objective of this proposal is to acquire an I-line stepper tool for high-throughput lithography with 350 nm feature resolution bridging the gap between electron-beam lithography and contact lithography. Nano-imprint and photolithography are usually done in separate machines and this proposal is to acquire an integrated machine that can do both simultaneously resulting in superior alignment. Numerous exciting projects will benefit from the acquisition of this equipment. Contact guidance studies using nanotopography, creating nanorachets for microfluidics, nanoelectrodes for energy, plasmonics are all high quality projects that will benefit from this acquisition. Overall, the projects are interesting and potentially transformative. The projects are cohesive and will rely on the stepper tool, it is well written and well organized proposal in all aspects. The PIs have the required expertise for use of this instrument in current and future research projects. The proposed tool will have a broad impact in research and education. The combination of projects including junior faculty with senior faculty is unique and well thought of. The acquisition of this tool will benefit the academic researchers and overall users for the UW NNIN node. The outreach efforts are broad and well described including involvement of students from community colleges, high schools and underrepresented minorities. The cleanroom facilities are already funded by NNIN, hence having this tool in the facility not only will serve a larger group of researchers, but also will be maintained well. More than100 academic users and about 40 industrial users are expected to use the tool.

Abstract We propose to develop a nucleic acid based point-of-care diagnostic for quantifying viral load (VL) in whole blood. The technology makes use of rapid RNA purification and reverse transcription recombinase polymerase amplification (RT-RPA) on an electrokinetic paper device for quantitative detection of HIV-1 RNA in less than 15 minutes. This technology development is generally applicable to viral diagnostics in complex biological samples, and here we focus on HIV-1 where no cost effective nucleic acid-based tests for point-of-care diagnostics are available. The HIV/AIDS epidemic is a major global health challenge, and is a leading cause of mortality and burden over the last decade. Initiation of antiretroviral therapy (ART) can maintain durable viral suppression, however viral load (VL) tests are needed to monitor the ongoing effectiveness of therapy, especially in prevention of mother to child transmission of HIV. Currently, the optimal tests for measuring HIV VL rely on molecular amplification methods that detect either HIV RNA or proviral DNA. A variety of commercial nucleic acid amplification technologies (NAATs) assays are available for these purposes but their complexity, sensitive reagents, cost, and hardware are prohibitively expensive and typically necessitate a fully functional centralized laboratory for their use. The logistics around specimen collection, testing, and transport results in delayed diagnosis (from 9 days to 5 months), diminished follow up with patients/guardians, and lost opportunity for life saving treatment. We propose an electrokinetic paper based nucleic acid amplification assay that can quantify HIV VL from whole blood in 15 minutes, with minimal user intervention, and no moving parts. Our innovative paper-based approach combines rapid extraction of RNA by isotachophoresis (ITP) with RT-RPA amplification of target nucleic acids. The diagnostic platform has integrated sample prep using a blood separation membrane, surfactant based virion lysis, and ITP RNA purification. ITP extracts the nucleic acid targets from fractionated plasma while focusing the RNA with RT-RPA reagents to accelerate the amplification reactions. The RPA reactions are quantified using fluorescence intensity and an internal control reaction. A mobile phone is used to power and control the extraction and reaction, measure the RPA reaction fluorescence, analyze the fluorescence data, and unambiguously report the VL to the clinician and transmit to the cloud. The platform will provide quantification of HIV VL in 15 minutes, for less than $10 per test, and minimal user intervention. The diagnostic will be validated over a wide range of HIV subtypes and evaluated using clinical whole blood samples from HIV/AIDS patients.

ABSTRACT COVID-19 is a severe respiratory tract infection caused by the newly discovered, and highly contagious, SARS- CoV-2 virus that emerged in late 2019 in Wuhan, China and has infected over 3 million people globally (> 1M US) and has caused over 215,000 deaths (58,000 US). SARS-CoV-2 RNA is the only sensitive and specific biomarker for diagnosis of an active COVID-19 infection and is diagnosed by reverse-transcription polymerase chain reaction (RT-PCR) in a central virology lab. Several CLIA-waived NAAT systems have been rapidly adapted for testing COVID-19, and have been granted the Emergency Use Authorization (EUA) for use at the point-of-care; however, their use is generally restricted to clinical sites because of the instrument, and/or protocol complexity, and high cost associated with the equipment. Self-administered nasal swabs have been shown to be an effective sample to detect COVID-19, and as a result the FDA is allowing their use as an acceptable specimen for COVID-19 laboratory testing, paving the way for home-based COVID NAT tests. We currently have a NIBIB project focused on the development and validation of a paper microfluidic based POC NAT for quantifying HIV Viral load from whole blood. Here, we propose to leverage this on-going effort to develop a COVID-19 Nucleic Acid Amplification Self Test (COAST) that can be performed at home to detect COVID-19 infections based on SARS-CoV-2 RNA. COAST is fully disposable test will detect as little as 5,000 cp/swab, have a COGS of less than $2.50, and will have sample-to-result within 30 minutes. In this proposal, our primary objectives are (1) optimizing and validating a sensitive and specific Recombinase Polymerase Amplification (RPA) isothermal amplification assay for the N-gene for SARS-CoV-2 RNA with lateral flow readout and (2) developing and evaluating the COAST home-based test with integrated sample preparation, isothermal amplification, lateral flow read-out. RPA is a low-temperature, isothermal amplification chemistry that can specifically detect a target with a wide range of genomic diversity and easily be integrated with LFA read-out. COAST has a novel elution tube, self-regulating positive temperature coefficient heaters, on-paper RPA amplification, and LFA readout. The RPA assay will be validated with de-identified SARS-CoV-2 RNA from COVID-19 patient samples collected by UWs Virology Lab and the COAST cartridge will be evaluated using mock nasal swabs with non-infectious targets. COVID-19 self-testing can drastically increase total testing numbers which can improve state and federal public health officials understanding of disease proliferation, as well as informing policy response (e.g. stay-at-home orders, school closures, etc.) and allocation of emergency response (for example distribution of PPE or ventilators). Self-testing can also reduce new infections by initiating prompt quarantine and public health contact tracing, especially in the case of asymptomatic or mildly symptomatic patients.

ABSTRACT Oral pre-exposure prophylaxis (PrEP), composed of tenofovir disoproxil fumarate and emtricitabine, is effective for preventing HIV acquisition, but PrEP efficacy is highly dependent on drug adherence. In several trials and implementation studies, PrEP clients have difficulties maintaining adequate adherence and persistence, and monitoring their PrEP use is challenging. PrEP providers have relied on self-reported adherence, which is often inaccurate and unreliable. The lack of an objective PrEP adherence monitoring tool has led to inefficient counseling and poor supportive care. To address these issues, we completed a randomized pharmacokinetic study to determine drug levels during controlled directly-observed PrEP. Longer-term metabolites, such as tenofovir-diphosphate (TFV-DP) (~17-day half-life), provide a more accurate picture of long-term PrEP adherence. We recently developed a novel enzymatic assay that semi-quantitatively measures the concentration of TFV-DP by measuring inhibition of reverse transcriptase, which is the cellular target of oral PrEP drugs. In this proposal, our primary objectives are optimizing the REverSe TRanscrIptase Chain Termination (RESTRICT) assay to measure drug concentrations of PrEP clients, to establish validation for CLIA criteria when implemented in a near-patient clinical lab, and to evaluate the feasibility and acceptability of using the RESTRICT assay for drug level measurement among PrEP clients and providers. We will test our central hypotheses with three specific aims: (1) to calibrate and optimize the RESTRICT assay for measuring long-term TFV-DP drug concentrations, compared to gold-standard liquid chromatography tandem mass spectrometry (LC-MS/MS) measurement; (2) to validate the RESTRICT assay for meeting established CLIA criteria to enable clinical reporting of an objective near-patient measure for monitoring long-term TFV-DP drug concentrations; (3) to evaluate the feasibility and acceptability of near-patient TFV-DP testing among PrEP clients and providers at a major PrEP clinic in Seattle. Our proposed study will be the first to validate a rapid, near-patient long-term objective measure of oral PrEP adherence. This study will also provide crucial data on the feasibility and acceptability of a novel approach for improving PrEP delivery and monitoring to prevent HIV transmission. The results of this study will develop a new tool that may help improve PrEP delivery in the US and worldwide.