Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Development of a light-powered microstructure : enhancing thermal actuation with near-infrared absorbent gold nanoparticles.

Development of microscale actuating technologies has considerably added to the toolset for interacting with natural components at the cellular level. Small-scale actuators and switches have potential in areas such as microscale pumping and particle manipulation. Thermal actuation has been used with asymmetric geometry to create large deflections with high force relative to electrostatically driven systems. However, many thermally based techniques require a physical connection for power and operate outside the temperature range conducive for biological studies and medical applications. The work presented here describes the design of an out-of-plane bistable switch that responds to near-infrared light with wavelength-specific response. In contrast to thermal actuating principles that require wired conductive components for Joule heating, the devices shown here are wirelessly powered by near -infrared (IR) light by patterning a wavelength-specific absorbent gold nanoparticle (GNP) film onto the microstructure. An optical window exists which allows near-IR wavelength light to permeate living tissue, and high stress mismatch in the bilayer geometry allows for large actuation at biologically acceptable limits. Patterning the GNP film will allow thermal gradients to be created from a single laser source, and integration of various target wavelengths will allow for microelectromechanical (MEMS) devices with multiple operating modes. An optically induced temperature gradient using wavelength-selective printable or spinnable coatings would provide a versatile method of wireless and non-invasive thermal actuation. This project aims to provide a fundamental understanding of the particle and surface interaction for bioengineering applications based on a “hybrid” of infrared resonant gold nanoparticles and MEMS structures. This hybrid technology has potential applications in light-actuated switches and other mechanical structures. Deposition methods and surface chemistry are integrated with three-dimensional MEMS structures in this work. The long-term goal of this project is a system of light-powered microactuators for exploring cells\u27 response to mechanical stimuli, adding to the fundamental understanding of tissue response to everyday mechanical stresses at the molecular level

Optoelectronic Tweezers for Microparticle and Cell Manipulation

An optical image-driven light induced dielectrophoresis (DEP) apparatus and method are described which provide for the manipulation of particles or cells with a diameter on the order of 100 micromillimeters or less. The apparatus is referred to as optoelectric tweezers (OET) and provides a number of advantages over conventional optical tweezers, in particular the ability to perform operations in parallel and over a large area without damage to living cells. The OET device generally comprises a planar liquid-filled structure having one or more portions which are photoconductive to convert incoming light to a change in the electric field pattern. The light patterns are dynamically generated to provide a number of manipulation structures that can manipulate single particles and cells or group of particles/cells. The OET preferably includes a microscopic imaging means to provide feedback for the optical manipulation, such as detecting position and characteristics wherein the light patterns are modulated accordingly

3D Microfluidics for Environmental Pathogen Detection and Single-cell Phenotype-to-Genotype Analysis

The emergence of microfluidic technologies has enabled the miniaturization of cell analysis processes, including nucleic acid analysis, single cell phenotypic analysis, single cell DNA and RNA sequencing, etc. Traditional chip fabrication via soft lithography cost thousands of dollars just in personnel training and capital cost. The design of these systems is also confined to two dimensions limited by their fabrication. To address the needs of smooth transition from technology to adoption by end-users, less complexity is urgently needed for microfluidics to be applied in pathogen detection under low-resource settings and more powerful integration of analyses to understand single cells. This dissertation presents my explorations in 3D microfluidics involving simulation-aided design of pretreatment devices for pathogen detection, fabrication through 3D printing, utilization of alternative commercial parts, and the combination with hydrogel material to link phenotypic analysis with in situ molecular detection for single cells. The main outputs of this dissertation are as follows: 1) COMSOL Multiphysics® was used to aid the design and understanding of microfluidic systems for environmental pathogen detection. In the development of an asymmetric membrane for concentration and digital detection of bacteria, the quantification requires Poisson distribution of cells into membrane pores; the flow field and particle trajectories were simulated to validate the cell distribution in capturing pores. In electrochemical bacterial DNA extraction, the hydroxide ion generation, species diffusion, and cation exchange were modeled to understand the pH gradient within the chamber. To address the overestimated risk by polymerase chain reactions (PCR) that detects all target nucleic acids regardless of cell viability, we developed a microfluidic device to carry out on-chip propidium monoazide (PMA) pretreatment. The design utilizes split-and-recombine (SAR) mixers for initial PMA-sample mixing and a serpentine flow channel containing herringbone structures for dark and light incubation. Ten SAR mixers were employed based on fluid flow and diffusion simulation. High-resolution 3D printing was used for prototyping. On-chip PMA pretreatment to differentiate live and dead bacterial cells in buffer and natural pond water samples was experimentally demonstrated. 2) Water-in-oil droplet-based microfluidic platforms for digital nucleic acid analysis eliminates the need for calibration that is required for qPCR-based environmental pathogen detection. However, utilizing droplet microfluidics generally requires fabrication of sub-100 µm channels and complicated operation of multiple syringe pumps, thus hindering the wide adoption of this powerful tool. We designed a disposable centrifugal droplet generation device made simply from needles and microcentrifuge tubes. The aqueous phase was added into the Luer-Lock of the commercial needle, with the oil at the bottom of the tube. The average droplet size was tunable from 96 μm to 334 μm and the coefficient of variance (CV) was minimized to 5%. For droplets of a diameter of 175 μm, each standard 20 μL reaction could produce ~10⁴ droplets. Based on this calculated compartmentalization, the dynamic range is theoretically from 0.5 to 3×10³ target copies or cells per μL, and the detection limit is 0.1 copies or cells per μL. 3) Based on the disposable droplet generation device, we further developed a novel platform that enables both high-throughput digital molecular detection and single-cell phenotypic analysis, utilizing nanoliter-sized biocompatible polyethylene glycol (PEG) hydrogel beads. The crosslinked hydrogel network in aqueous phase adds additional robustness to droplet microfluidics by allowing reagent exchange. The hydrogel beads demonstrated enhanced thermal stability, and achieved uncompromised efficiencies in digital PCR, digital loop-mediated isothermal amplification (dLAMP), and single cell phenotyping. The crosslinked hydrogel network highlights the prospective linkage of various subsequent molecular analyses to address the genotypic differences between cellular subpopulations exhibiting distinct phenotypes. This platform has the potential to advance the understanding of single cell genotype-to-phenotype correlations. 4) For effective sorting of the hydrogel beads after single cell phenotyping, a gravity-driven acoustic fluorescence-based hydrogel beads sorter was developed. The design involves a 3D-printed microfluidic tube, two sequential photodetectors, acoustic actuator, and a control system. Instead of bulky syringe pumps used in traditional cell or droplet sorting, this invention drives beads suspended in heavier fluorinated oil simply by buoyancy force to have the beads float through a vertical channel. Along the channel, sequential photodetectors quantify the bead acceleration and inform the action of downstream acoustic actuator. Hydrogel beads with different fluorescence intensity level were led into different collection chambers. The developed sorter promises cheap instrumentation, easy operation, and low contamination for beads sorting, and thus the full establishment of the single cell phenotype-genotype link. In summary, the work in this dissertation established a) the simulation-aided design and 3D printing to reduce the complexity of microfluidics, and thus lowered its barrier for environmental applications, b) a simple and disposable device using cheap commercial components to produce monodispersed water-in-oil droplets to enable easy adoption of droplet microfluidics by non-specialized labs, c) a hydrogel bead-based analysis platform that links single-cell phenotype and genotype to open new research avenues, and d) a gravity-driven portable bead sorting system that may extend to a broader application of hydrogel microfluidics to point of care and point of sample collection. These simple-for-end-user solutions are envisioned to open new research avenues to tackle problems in antibiotic heteroresistance, environmental microbial ecology, and other related fundamental problems.</p

Optoelectronic tweezers for microparticle and cell manipulation

An optical image-driven light induced dielectrophoresis (DEP) apparatus and method are described which provide for the manipulation of particles or cells with a diameter on the order of 100 .mu.m or less. The apparatus is referred to as optoelectric tweezers (OET) and provides a number of advantages over conventional optical tweezers, in particular the ability to perform operations in parallel and over a large area without damage to living cells. The OET device generally comprises a planar liquid-filled structure having one or more portions which are photoconductive to convert incoming light to a change in the electric field pattern. The light patterns are dynamically generated to provide a number of manipulation structures that can manipulate single particles and cells or groups of particles/cells. The OET preferably includes a microscopic imaging means to provide feedback for the optical manipulation, such as detecting position and characteristics wherein the light patterns are modulated accordingly

Microdevices and Microsystems for Cell Manipulation

Microfabricated devices and systems capable of micromanipulation are well-suited for the manipulation of cells. These technologies are capable of a variety of functions, including cell trapping, cell sorting, cell culturing, and cell surgery, often at single-cell or sub-cellular resolution. These functionalities are achieved through a variety of mechanisms, including mechanical, electrical, magnetic, optical, and thermal forces. The operations that these microdevices and microsystems enable are relevant to many areas of biomedical research, including tissue engineering, cellular therapeutics, drug discovery, and diagnostics. This Special Issue will highlight recent advances in the field of cellular manipulation. Technologies capable of parallel single-cell manipulation are of special interest

Real-time measurement, analysis, and control in microfluidic systems for personalized medicine and designer materials

The field of microfluidics has enabled the development of powerful tools for analyzing and manipulating phenomena at the micro- and nano-scales, ranging from chemical analysis of biological samples to controlled synthesis of colloidal materials. In this dissertation we explore four unique platforms for real-time microfluidic measurement, analysis, and control systems with applications at the intersection of biomedicine and materials engineering. First, we show that a real-time biosensor can be used to perform closed-loop control of drug concentrations in the bloodstream of live animals. Second, we show that a commercially available cell-sorting instrument can be used to sort heterogeneous suspensions of synthetic microparticles based on shape using optical scattering measurements, resulting in monodisperse microparticle suspensions with well-defined morphology. Third, we report preliminary results for an image-based cell and microparticle sorter capable of sorting objects using two-dimensional high-speed microscopy and real-time image analysis. Finally, we report a contamination-resistant microfluidic assay for quantitative genetic detection based on real-time loop-mediated isothermal amplification, improving the robustness of point-of-care pathogen detection techniques

Technology assessment and feasibility study of high-throughput single cell force spectroscopy

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 72-83).In the last decade, the field of single cell mechanics has emerged with the development of high resolution experimental and computational methods, providing significant amount of information about individual cells instead of the averaged characteristics provided by classical assays from large populations of cells. These single cell mechanical properties correlate closely with the intracellular organelle arrangement and organization, which are determined by load bearing cytoskeleton network comprised of biommolecules. This thesis will assess the feasibility of a high throughput single cell force spectroscopy using an atomic force microscopy (AFM)-based platform. A conventional AFM set-up employs a single cantilever probe for force measurement by using laser to detect the deflection of the cantilever structure, and usually can only handle one cell at a time. To improve the throughput of the device, a modified scheme to make use of cantilever based array is proposed and studied in this project. In addition, to complement the use of AFM array, a novel cell chip design is also presented for the fine positioning of cells in coordination with AFM cantilevers. The advantages and challenges of the system are analyzed too. To assess the feasibility of developing this technology, the commercialization possibility is discussed with intellectual property research, market analysis, cost modeling and supply chain positioning. Conclusion about this technology and its market prospect is drawn at the end of the thesis.by He Cheng.M.Eng

DRI Renewable Energy Center (REC) (NV)

The primary objective of this project was to utilize a flexible, energy-efficient facility, called the DRI Renewable Energy Experimental Facility (REEF) to support various renewable energy research and development (R&D) efforts, along with education and outreach activities. The REEF itself consists of two separate buildings: (1) a 1200-ft2 off-grid capable house and (2) a 600-ft2 workshop/garage to support larger-scale experimental work. Numerous enhancements were made to DRI's existing renewable power generation systems, and several additional components were incorporated to support operation of the REEF House. The power demands of this house are satisfied by integrating and controlling PV arrays, solar thermal systems, wind turbines, an electrolyzer for renewable hydrogen production, a gaseous-fuel internal combustion engine/generator set, and other components. Cooling needs of the REEF House are satisfied by an absorption chiller, driven by solar thermal collectors. The REEF Workshop includes a unique, solar air collector system that is integrated into the roof structure. This system provides space heating inside the Workshop, as well as a hot water supply. The Workshop houses a custom-designed process development unit (PDU) that is used to convert woody biomass into a friable, hydrophobic char that has physical and chemical properties similar to low grade coal. Besides providing sufficient space for operation of this PDU, the REEF Workshop supplies hot water that is used in the biomass treatment process. The DRI-REEF serves as a working laboratory for evaluating and optimizing the performance of renewable energy components within an integrated, residential-like setting. The modular nature of the system allows for exploring alternative configurations and control strategies. This experimental test bed is also highly valuable as an education and outreach tool both in providing an infrastructure for student research projects, and in highlighting renewable energy features to the public

A NEW CONDUCTIVE MEMBRANE-BASED MICROFLUIDIC PLATFORM FOR ELECTROKINETIC APPLICATIONS

Micro-total-analysis-system (uTAS), a technology branches from the broader concept, microfluidics, has emerged as a powerful tool for many biological and chemical applications. uTAS typically features sample-to-answer designs, minute sample assumption and short processing time, which are highly desired in point-of-care diagnostics or high-throughput chemical analysis. Despite a large number of microfluidic devices reported with the uTAS concept, most designs were detection and sensitivity focused, ignored the necessary sample preparation steps. In recent years, the increasing demand for chip automation has boosted research efforts on sample preparation. Electric force serves as one of the most applicable tools among on-chip sample processing techniques due to its portable and easy-integrating nature. To date, research has yielded a large number of designs utilizing electric field as a driving force, also known as electrokinetics, for on-chip sample processing, such as sample purification, enrichment, mixing and sorting. One biggest issue researchers countered using electric field is undesired surface reactions that may cause Faradaic reactions, electrode corrosion, and contaminations. While several microfluidic platforms have been developed to address this issue, there are still growing efforts to create new micro-design that are capable of providing sufficient electric field with improved stability, portability, and robustness. This thesis seeks to address the electrokinetic-based on-chip sample preparation issue in two aspects, continuity and flow control, which represent two main challenges of on-chip sample preparation: a limited capability to continuously process samples and lacking necessary modules for precise flow control under large extent chip integration. We first developed a new electrokinetic platform with integrated conductive membranes to effectively generate a uniform three-dimensional electric field inside microfluidic channels. The new design also has proved superiorities in avoiding surface reactions, improving portability, and reducing the fabrication cost. We then solved the continuity issue with a free flow electrophoresis device created from the platform. The free flow nature of the device allows for continuous sample throughput while adding electric field perpendicularly offers additional manipulating factors. Utilizing the newly developed free flow electrokinetic chip, we have successfully demonstrated two common on-chip sample processing functions: parallel separation and sample enrichment. On the other hand, the flow control issue is tackled by creating essential on-chip control modules under microfluidic setting. We have designed several microfluidic units with the platform to facilitate on-chip flow regulation, including micro-pumps, a sample injector, a local flow meter and a potential automatic control panel. All the flow control modules can be directly integrated into any soft lithography based sample processing modules without affecting the original designs, which significantly eases the integration difficulty. The ultimate goal of this research shall lead to a microfluidic platform that can perform essential on-chip sample pretreatments in a continuous manner and allows need-based customization. The platform shall be easily integrated with essential power functions and feedback mechanisms for automatic flow control, which offer a possibility to real highly integrated portable devices. Eventually, we can build the real uTAS by combining the platform with our real-time biosensor and turning it into a sample-to-answer uTAS. In the first chapter of this thesis, a general background correlated to my research work is provided. The introduction includes the uTAS concept and its related technologies, explains the increasing demand for on-chip sample preparation techniques, and discusses current sample process modules using electrokinetic force. It leads to Chapter 2, where I summarize the current electrokinetic-based microfluidic platforms developed to address the surface reaction issue. Then we propose the new platform along with a theoretical model to characterize this design. An extensive comparison between available designs follows to demonstrate the advantages of this new platform, including the comparison specifically focusing on surface reactions. A detailed fabrication process flow is demonstrated in the end, showing how to fabricate this new platform design using one -step photolithography. Then the thesis splits into two parallel blocks, corresponding to the two challenges of on-chip sample preparation. The continuity challenge is addressed on the first block, chapter 3, where free flow electrophoresis device is presented and followed by two demonstrations of on-chip sample pretreatment functions: mixture separation and molecule enrichment. The second block of this thesis discusses the importance of on-chip flow control and the main obstacles that current technologies struggle with. Essential modules for on-chip flow control, such as electro-osmotic pumps, fluid regulation, sample injection techniques, pressure and flow meters, will be demonstrated in chapter 4-6, respectively. In conclusion, I will summarize all my previous research work and how to sketch the big picture of on-chip sample preparation with this platform. The results shall provide guidelines and inspirations for future on-chip sample preparation research