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The porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and porcine deltacoronavirus (PDCoV) are emerging/reemerging coronaviruses (CoVs) of neonatal pigs that cause great economic losses to pig farms and pork processors. Specific, rapid, and simple multiplex detection of these viruses is critical to enable prompt implementation of appropriate control measures. Conventional methods for molecular diagnosis require skilled personnel and relatively sophisticated equipment, restricting their use in centralized laboratories. We developed a low-cost, rapid, semi-quantitative, field deployable, 3D-printed microfluidic device for auto-distribution of samples and self-sealing and real-time and reverse transcription-loop-mediated isothermal amplification (RT-LAMP), enabling the co-detection of PEDV, TGEV and PDCoV within 30 minutes. Our assay's analytical performance is comparable with a benchtop, real-time RT-LAMP assay and the gold standard quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay with limits of detection of 10 genomic copies per reaction for PEDV and PDCoV, and 100 genomic copies per reaction for TGEV. Evaluation of clinical specimens from diseased pigs with our microfluidic device revealed excellent concordance with both benchtop RT-LAMP and qRT-PCR. Our portable RT-LAMP microfluidic chip will potentially facilitate simple, specific, rapid multiplexed detection of harmful infections in minimally equipped veterinary diagnostic laboratories and on-site in pigs' farms.

Molecular detection of pathogenic nucleic acids from patient samples requires incubating biochemical reactions at specific temperatures to amplify DNA. This incubation is typically carried out with an electrical heater and a temperature controller. To reduce test cost, to eliminate the need for manufacturing incubators, which may require significant time, and to enable electricity-free operation, we use energetic compounds such as an Mg(Fe) alloy mixed with a phase-change material (PCM) that undergoes phase transformation at the desired incubation temperature. We dubbed this composite Energetic Phase Change Material (EPCM). When the EPCM is brought into contact with water, the magnesium alloy interacts with the water to produce heat. The EPCM heats up to its phase transition temperature. Any excess heat is absorbed as latent heat and the system is maintained at its desired incubation temperature, independent of ambient temperatures, long enough to facilitate enzymatic amplification. The EPCM together with colorimetric amplicon detection facilitates an inexpensive, disposable, point-of-need diagnostic test that does not require any electric power. We demonstrate the feasibility of our approach by detecting SARS-Cov-2 in saliva samples either without any instrumentation or with a palm-size CCD camera that enables us to follow the amplification process in real time.

Traditionally, plasma is extracted from whole blood using centrifuges in clinical laboratories, which is unsuitable for on-site testing. For point-of-care diagnostics, for example in HIV tests, to ensure the detection sensitivity for low-abundance analytical targets, a relatively large volume of plasma needs to be extracted from milliliters of blood with a simpler and easier-to-operate method than centrifugation. We report the development of a membrane-assisted, sedimentation-facilitated plasma separator with a multifunctional deformable chamber, which is able to perform plasma separation from undiluted whole blood in a short time. Multiple steps related to plasma separation, including cell sedimentation, cell filtration, and plasma driving and discharging, are all performed in or through the multifunctional deformable chamber equipped with a top-layer porous membrane, which significantly reduces the device complexity. Assisted by a simple jig or even hands, plasma separation can be conveniently performed upon mechanical actuation of the deformable chamber. Within 8 min, ∼130 μL of plasma can be conveniently extracted with the described device from 2.3 mL of whole blood. It has been demonstrated that HIV antibodies or virus spiked in whole blood can be successfully detected with reasonable sensitivity from the extracted plasma with the described pump-free device.

Liquid biopsy is a highly promising method for non-invasive detection of tumor-associated nucleic acid fragments in body fluids but is challenged by the low abundance of nucleic acids of clinical interest and their sequence homology with the vast background of nucleic acids from healthy cells. Recently, programmable endonucleases such as clustered regularly interspaced short palindromic repeat (CRISPR) associated protein (Cas) and prokaryotic Argonautes have been successfully used to remove background nucleic acids and enrich mutant allele fractions, enabling their detection with deep next generation sequencing (NGS). However, the enrichment level achievable with these assays is limited by futile binding events and off-target cleavage. To overcome these shortcomings, we conceived a new assay (Programmable Enzyme-Assisted Selective Exponential Amplification, PASEA) that combines the cleavage of wild type alleles with concurrent polymerase amplification. While PASEA increases the numbers of both wild type and mutant alleles, the numbers of mutant alleles increase at much greater rates, allowing PASEA to achieve an unprecedented level of selective enrichment of targeted alleles. By combining CRISPR-Cas9 based cleavage with recombinase polymerase amplification, we converted samples with 0.01% somatic mutant allele fractions (MAFs) to products with 70% MAFs in a single step within 20 min, enabling inexpensive, rapid genotyping with such as Sanger sequencers. Furthermore, PASEA's extraordinary efficiency facilitates sensitive real-time detection of somatic mutant alleles at the point of care with custom designed Exo-RPA probes. Real-time PASEA' performance was proved equivalent to clinical amplification refractory mutation system (ARMS)-PCR and NGS when testing over hundred cancer patients' samples. This strategy has the potential to reduce the cost and time of cancer screening and genotyping, and to enable targeted therapies in resource-limited settings.

The importance of medical diagnostics, and specifically, tests for infectious agents such as viruses, is well recognized, and in fact, are a crucial component of efforts to control pandemics and mitigate their effects on public health. A long-established trend is the development of low-cost, easy-to-use point-of-care (POC) diagnostics to provide pervasive, timely testing independent of laboratories and other medical infrastructure. The technology of POC tests is widely accessible to engineering students, and there are many opportunities and avenues for innovation, including Smartphone-based platforms and integration with the Internet of Medical Things (IoMT). We discuss the design, demonstration, and testing of POC virus testing, including tests applicable to COVID-19, as Senior Design Projects for undergraduate mechanical, electrical, and manufacturing engineering majors.

Hand hygiene compliance is one of the most effective means to prevent the spread of infections and diseases. The centers for disease control and prevention (CDC) recommends washing hands for at least 20 s. However, current hand hygiene compliance monitoring relies on either direct observation or complex electronic compliance monitoring systems. Here, we reported a simple, inexpensive, compact, wearable fluid sensing device, dubbed “smart ring”, for real-time monitoring hand hygiene compliance. The proposed smart ring was prototyped by 3D printing technology and includes an electrochemical fluid sensor, a LED indicator and an embedded electronic board. The ring is capable of detecting hand-washing events and monitoring hand-washing time without need for any expensive electronic monitoring instrument and well-trained personnel. It has been successfully demonstrated to detect a variety of hand-washing agents, such as tap water, soaps, sanitizers, and antimicrobial agents. Such a simple, compact, wearable device could open the door to improve hand hygiene compliance and reduce infection rates in our daily life, especially in hospitals, food businesses and schools.

Seneca Valley virus (SVV) is related to vesicular disease in pigs, and its clinical symptoms are indistinguishable from other notifiable clinical symptoms of vesicular disease such as foot-and-mouth disease. The rapid and accurate detection of SVV is essential to confirm the pathogenic factors and initiate the implementation of control measures. The development of a rapid, simple, convenient, and low-cost molecular (nucleic acid amplification) test that can be used at the sample collection point has been identified as a key component for controlling SVV. This study describes the development and demonstration of recombinase polymerase amplification (RPA) test targeting the conserved regions of SVV for detection of SVV. The Primers and probes designed by us have shown good sensitivity and specificity in RPA test, which is helpful for RPA to be an effective tool for rapid diagnosis of SVV.

Simple Summary Bovine papillomatosis is a disease caused by bovine papillomavirus (BPV), which is a diverse group of oncogenic viruses that challenge cattle industry, resulting in significant economic losses. The present study investigated the occurrence of bovine papillomatosis among cattle (n = 308) with cutaneous warts on the head and neck from New valley Province, Egypt through molecular detection of BPV-1, -2, -4, -5, and -10. The work also involved a phylogenetic analysis of the positive samples for detection of the genetic relatedness of the virus. Interestingly, BPV-1 DNA was detected in 84.6% of the collected samples. Furthermore, the study included the development of an isothermal nucleic acid amplification test, which is a field test combining molecular and lateral flow immunoassays for point-of-need testing appropriate for veterinary use in resource-limited settings. Collectively, our study provided interesting data related to the combined use of molecular and immunoassays methods in the detection of the virus besides better understanding the genetic relatedness of the circulating genotypes of BPV-1 in Egypt. Our study suggested further research to explore more about the other genotypes of BPV in the Egyptian environment that could be helpful for the implementation of control strategies for combating this disease. Abstract Bovine papillomatosis is a viral disease of cattle causing cutaneous warts. A diagnosis of this viral infection is very mandatory for combating the resulting economic losses. Given the limited data available about bovine papillomavirus (BPV) in Egypt, the present study involved the molecular diagnosis of bovine papillomavirus type-1 (BPV-1), -2, -4, -5, and -10 in cattle presenting cutaneous warts on the head and neck from New Valley Province, Egypt. The phylogenetic analysis of the detected types of BPV was also performed, followed by developing a point-of-need molecular assay for the rapid identification of identified BPV types. In this regard, a total of 308 cattle from private farms in Egypt were clinically examined, of which 13 animals presented cutaneous warts due to suspected BPV infection. The symptomatic animals were treated surgically, and biopsies from skin lesions were collected for BPV-1, -2, -4, -5, and -10 molecular identification using polymerase chain reaction (PCR). The presence of BPV-1 DNA was confirmed in 11 collected samples (84.6%), while BPV-2, -4, -5, and -10 were not detected. Sequencing of the PCR products suggested the Egyptian virus is closely related to BPV found in India. An isothermal nucleic acid amplification test (NAAT) with labeled primers specific for the BPV-1 L1 gene sequence, and based on recombinase polymerase amplification (RPA), in combination with a lateral flow strip assay for the detection of RPA products, was developed and tested. The point-of-need molecular assay demonstrated a diagnostic utility comparable to PCR-based testing. Taken together, the present study provides interesting molecular data related to the occurrence of BPV-1 in Egypt and reveals the genetic relatedness of the Egyptian BPV-1 with BPV-1 found in buffalo in India. In addition, a simple, low-cost combined test was also validated for diagnosis of the infection. The present study suggests the necessity of future investigations about the circulating strains of the virus among the cattle in Egypt to assess their genetic relatedness and better understand the epidemiological pattern of the disease.

Highlights • A closed tube, single-step-real-time-RT-LAMP assay was developed for detection and semi-quantification of IBV in closed tube. • The least limit of detection of our assay is 1 EID50/ ml. • Clinical evaluation of samples from diseased chickens using our assay shows a very good concordance with RT-qPCR assay., Infectious bronchitis (IB) is a viral infection of the chicken respiratory tract that causes substantial economic burden on the industry. Simple, specific and rapid diagnosis of this disease is critical for the initiation of appropriate control measures. Conventional molecular diagnostic methods require a relatively sophisticated equipment and skilled staff. Here we describe a rapid, simple, semi-quantative, closed-tube, single-step, real-time- reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for IB and compare our assay with quantative, reverse transcription- polymerase chain reaction (RT-qPCR). The limit of detection (LOD) of our RT-LAMP assay is 1 EID50/ ml. Clinical evaluation of samples from diseased chickens with our RT-LAMP showed a very good concordance with RT-qPCR. Our assay enables simple, specific, rapid molecular detection and semi-quantification of the infectious bronchitis virus (IBV) in veterinary diagnostic laboratories. Furthermore, our RT-LAMP detection is carried out in a sealed tube, eliminating the risk of false-positive results in subsequent tests because of any contamination of the work area as in the case of lateral flow strip or gel electrophoresis-based amplicon detection.

Widely accessible, inexpensive, easy-to-use consumer 3D printers, such as desktop stereolithography (SLA) and fused-deposition modeling (FDM) systems are increasingly employed in prototyping and customizing miniaturized fluidic systems for diagnostics and research. However, these 3D printers are generally limited to printing parts made of only one material type, which limits the functionality of the microfluidic devices without additional assembly and bonding steps. Moreover, mating of different materials requires good sealing in such microfluidic devices. Here, we report methods to print hybrid structures comprising a hard, rigid component (clear polymethacrylate polymer) printed by a low-cost SLA printer, and where the first printed part is accurately mated and adhered to a second, soft, flexible component (thermoplastic polyurethane elastomer) printed by an FDM printer. The prescribed mounting and alignment of the first-printed SLA-printed hard component, and its pre-treatment and heating during the second FDM step, can produce leak-free bonds at material interfaces. To demonstrate the utility of such hybrid 3D-printing, we prototype and test three components: i) finger-actuated pump, ii) quick-connect fluid coupler, and iii) nucleic acid amplification test device with screw-type twist sealing for sample introduction.

Molecular diagnostics that involve nucleic acid amplification tests (NAATs) are crucial for prevention and treatment of infectious diseases. In this study, we developed a simple, inexpensive, disposable, fully 3D printed microfluidic reactor array that is capable of carrying out extraction, concentration and isothermal amplification of nucleic acids in variety of body fluids. The method allows rapid molecular diagnostic tests for infectious diseases at point of care. A simple leak-proof polymerization strategy was developed to integrate flow-through nucleic acid isolation membranes into microfluidic devices, yielding a multifunctional diagnostic platform. Static coating technology was adopted to improve the biocompatibility of our 3D printed device. We demonstrated the suitability of our device for both end-point colorimetric qualitative detection and real-time fluorescence quantitative detection. We applied our diagnostic device to detection of Plasmodium falciparum in plasma samples and Neisseria meningitides in cerebrospinal fluid (CSF) samples by loop-mediated, isothermal amplification (LAMP) within 50 minutes. The detection limits were 100 fg for P. falciparum and 50 colony-forming unit (CFU) for N. meningitidis per reaction, which are comparable to that of benchtop instruments. This rapid and inexpensive 3D printed device has great potential for point-of-care molecular diagnosis of infectious disease in resource-limited settings.

To enable inexpensive molecular detection at the point-of-care and at home with minimal or no instrumentation, it is necessary to streamline unit operations and store reagents refrigeration-free. To address this need, a multifunctional enzymatic amplification reactor that combines solid-phase nucleic acid extraction, concentration, and purification; refrigeration-free storage of reagents with just-in-time release; and enzymatic amplification is designed, prototyped, and tested. A nucleic acid isolation membrane is placed at the reactor's inlet, and paraffin-encapsulated reagents are prestored within the reactor. When a sample mixed with chaotropic agents is filtered through the nucleic acid isolation membrane, the membrane binds nucleic acids from the sample. Importantly, the sample volume is decoupled from the reaction volume, enabling the use of relatively large sample volumes for high sensitivity. When the amplification reactor's temperature increases to its operating level, the paraffin encapsulating the reagents melts and moves out of the way. The reagents are hydrated, just-in-time, and the polymerase reaction proceeds. The amplification process can be monitored, in real-time. We demonstrate our reactors' ability to amplify both DNA and RNA targets using polymerase with both reverse-transcriptase and strand displacement activities to obtain sensitivities on-par with benchtop equipment and a shelf life exceeding 6 months.

BACKGROUND The wide array of pathogens responsible for infectious diseases makes it difficult to identify causative pathogens with single-plex tests. Although multiplex PCR detects multiple targets, it is restricted to centralized laboratories, which delays test results or makes multiplexing unavailable, depriving healthcare providers of critical, real-time information. METHODS To address the need for point-of-care (POC) highly multiplexed tests, we propose the 2-stage, nested-like, rapid ( RESULTS In experiments on a benchtop and in a microfluidic format, RAMP demonstrated high level of multiplexing (≥16); high sensitivity (i.e., 1 plaque-forming unit of Zika virus) and specificity (no false positives or negatives); speed ( CONCLUSIONS RAMP is a hybrid, 2-stage, rapid, and highly sensitive and specific assay with extensive multiplexing capabilities, combining the advantages of RPA and LAMP, while circumventing their respective shortcomings. RAMP can be used in the lab, but one of its distinct advantages is amenability to simple implementation in a microfluidic format for use at the POC, providing healthcare personnel with an inexpensive, highly sensitive tool to detect multiple pathogens in a single sample, on site.

Detection of disease-associated, cell-free nucleic acids enables early diagnostics, genotyping, and personalized therapy, but is challenged by their low concentration and sequence homology with abundant wild-type nucleic acids. We describe a novel approach, dubbed NAVIGATER, for Nucleic Acid enrichment Via DNA-Guided Argonaute from Thermus thermophilus (TtAgo) that allows for specific cleavage of guide-complementary DNA and RNA with single nucleotide precision. NAVIGATER greatly increases the fractions of rare alleles, enhancing the sensitivity of downstream detection such as ddPCR, sequencing, and clamped enzymatic amplification. We demonstrated 60-fold enrichment of KRAS G12D and nearly 100-fold increased sensitivity of clamped-PCR (PNA and XNA-PCR), enabling detection of low-frequency (0.01%) mutant alleles (∼1 copy) in blood samples of pancreatic cancer patients. NAVIGATER surpasses Cas9-DASH, identifying more mutation-positive samples when combined with XNA-PCR. Moreover, TtAgo does not require the target to contain any specific (PAM-like) motifs; is a multi-turnover enzyme; cleaves ssDNA, dsDNA, and RNA targets in a single assay; and operates at elevated temperatures, providing high selectivity and compatibility with polymerases. The here-described NAVIGATER approach has important advantages over other enrichment methods.

Nucleic acid amplification-based diagnostics offer rapid, sensitive, and specific means for detecting and monitoring the progression of infectious diseases. However, this method typically requires extensive sample preparation, expensive instruments, and trained personnel. All of which hinder its use in resource-limited settings, where many infectious diseases are endemic. Here, we report on a simple, inexpensive, minimally-instrumented, smart cup platform for rapid, quantitative molecular diagnostics of pathogens at the point of care. Our smart cup takes advantage of water-triggered, exothermic chemical reaction to supply heat for the nucleic acid-based, isothermal amplification. The amplification temperature is regulated with a phase-change material (PCM). The PCM maintains the amplification reactor at a constant temperature, typically, 60-65°C, when ambient temperatures range from 12 to 35°C. To eliminate the need for an optical detector and minimize cost, we use the smartphone's flashlight to excite the fluorescent dye and the phone camera to record real-time fluorescence emission during the amplification process. The smartphone can concurrently monitor multiple amplification reactors and analyze the recorded data. Our smart cup's utility was demonstrated by amplifying and quantifying herpes simplex virus type 2 (HSV-2) with LAMP assay in our custom-made microfluidic diagnostic chip. We have consistently detected as few as 100 copies of HSV-2 viral DNA per sample. Our system does not require any lab facilities and is suitable for use at home, in the field, and in the clinic, as well as in resource-poor settings, where access to sophisticated laboratories is impractical, unaffordable, or nonexistent.

The recent outbreak of Zika virus (ZIKV) infection in the Americas and its devastating impact on fetal development have prompted the World Health Organization (WHO) to declare the ZIKV pandemic as a Public Health Emergency of International Concern. Rapid and reliable diagnostics for ZIKV are vital because ZIKV-infected individuals display no symptoms or nonspecific symptoms similar to other viral infections. Because immunoassays lack adequate sensitivity and selectivity and are unable to identify active state of infection, molecular diagnostics are an effective means to detect ZIKV soon after infection and throughout pregnancy. We report on a highly sensitive reverse-transcription loop-mediated, isothermal amplification (RT-LAMP) assay for rapid detection of ZIKV and its implementation in a simple, easy-to-use, inexpensive, point-of-care (POC) disposable cassette that carries out all the unit operations from sample introduction to detection. For thermal control of the cassette, we use a chemically heated cup without a need for electrical power. Amplification products are detected with leuco crystal violet (LCV) dye by eye without a need for instrumentation. We demonstrated the utility of our POC diagnostic system by detecting ZIKV in oral samples with sensitivity of 5 plaque-forming units (PFU) in less than 40 min. Our system is particularly suitable for resource-poor settings, where centralized laboratory facilities, funds, and trained personnel are in short supply, and for use in doctors’ offices, clinics, and at home.

To meet stringent limit-of-detection specifications for low abundance target molecules, a relatively large volume of plasma is needed for many blood-based clinical diagnostics. Conventional centrifugation methods for plasma separation are not suitable for on-site testing or bedside diagnostics. Here, we report a simple, yet high-efficiency, clamshell-style, superhydrophobic plasma separator that is capable of separating a relatively large volume of plasma from several hundred microliters of whole blood (finger-prick blood volume). The plasma separator consists of a superhydrophobic top cover with a separation membrane and a superhydrophobic bottom substrate. Unlike previously reported membrane-based plasma separators, the separation membrane in our device is positioned at the top of the sandwiched whole blood film to increase the membrane separation capacity and plasma yield. In addition, the device’s superhydrophobic characteristics (i) facilitates the formation of well-defined, contracted, thin blood film with a high contact angle; (ii) minimizes biomolecular adhesion to surfaces; (iii) increases blood clotting time; and (iv) reduces blood cell hemolysis. The device demonstrated a “blood in-plasma out” capability, consistently extracting 65±21.5 μL of plasma from 200 μL of whole blood in less than 10 min without electrical power. The device was used to separate plasma from Schistosoma mansoni genomic DNA-spiked whole blood with a recovery efficiency of > 84.5 ± 25.8 %. The S. mansoni genomic DNA in the separated plasma was successfully tested on our custom-made microfluidic chip by using loop mediated isothermal amplification (LAMP) method.

Detection of disease-associated, cell-free nucleic acids in body fluids enables early diagnostics, genotyping and personalized therapy, but is challenged by the low concentrations of clinically significant nucleic acids and their sequence homology with abundant wild-type nucleic acids. We describe a novel approach, dubbed NAVIGATER, for increasing the fractions of Nucleic Acids of clinical interest Via DNA-Guided Argonaute from Thermus thermophilus (TtAgo). TtAgo cleaves specifically guide-complementary DNA and RNA with single nucleotide precision, greatly increasing the fractions of rare alleles and, enhancing the sensitivity of downstream detection methods such as ddPCR, sequencing, and clamped enzymatic amplification. We demonstrated 60-fold enrichment of the cancer biomarker KRAS G12D and ∼100-fold increased sensitivity of Peptide Nucleic Acid (PNA) and Xenonucleic Acid (XNA) clamp PCR, enabling detection of low-frequency (

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A systems approach combining algae aquaculture for biofuels, photovoltaic solar electric generation, and a subsystem for atmospheric CO2 capture as a carbon source for the algae, is developed as a platform and testbed for student engineering design projects. This work serves as a hands-on learning design project for engineering undergraduates in renewable energy, industrial microbiology, and sustainable and ‘green’ technology. Fully-instrumented and automated tabletop systems for circulating algae cultures in plastic fluidic channels integrated with silicon solar cells are designed, prototyped and tested with the aim of optimizing the yields and solar energy utilization.

Robotic ultrasonic welding monitored in realtime with a force sensor and infrared thermal imaging camera is developed as an instructional project and laboratory component for undergraduate engineering education. The broad aim is to integrate robotics, plastic component manufacture, and thermal imaging with a unified theme. A secondary aim is to adapt ultrasonic welding for rapid prototyping as a tool for student design projects. Plastic parts for microsystems, such as lab-on-a-chip devices, made by laser cutting or 3d printing, are ultrasonically welded and tensile-stress tested and leaked checked.

Rapid and quantitative molecular diagnostics in the field, at home, and at remote clinics is essential for evidence-based disease management, control, and prevention. Conventional molecular diagnostics requires extensive sample preparation, relatively sophisticated instruments, and trained personnel, restricting its use to centralized laboratories. To overcome these limitations, we designed a simple, inexpensive, hand-held, smartphone-based mobile detection platform, dubbed “smart-connected cup” (SCC), for rapid, connected, and quantitative molecular diagnostics. Our platform combines bioluminescent assay in real-time and loop-mediated isothermal amplification (BART-LAMP) technology with smartphone-based detection, eliminating the need for an excitation source and optical filters that are essential in fluorescent-based detection. The incubation heating for the isothermal amplification is provided, electricity-free, with an exothermic chemical reaction, and incubation temperature is regulated with a phase change material. A custom Android App was developed for bioluminescent signal monitoring and analysis, target quantification, data sharing, and spatiotemporal mapping of disease. SCC’s utility is demonstrated by quantitative detection of Zika virus (ZIKV) in urine and saliva and HIV in blood within 45 min. We demonstrate SCC’s connectivity for disease spatiotemporal mapping with a custom-designed website. Such a smart- and connected-diagnostic system does not require any lab facilities and is suitable for use at home, in the field, in the clinic, and particularly in resource-limited settings in the context of Internet of Medical Things (IoMT).

Developments and progress in thin (~20 micron) monocrystalline and multicrystalline silicon solar cells for the last 10 years (2007 onward) are surveyed. Fabrication approaches include: (1) controlled wafer thinning for free-standing thin silicon cells, (2) silicon layer transfer methods that permit reuse of silicon substrates and include newer techniques employing formation of porous silicon or patterned surface regions to facilitate the release of a silicon layer for subsequent attachment to a surrogate substrate, and (3) various methods of recrystallizing silicon films deposited on glass using scanning laser or electron beams. Also a wide variety of optical enhancement schemes featuring nanostructured surfaces and nanoscale components achieving levels of optical absorption and photocurrents close to the theoretical maximum for crystalline silicon are reviewed. The required process engineering for translation from laboratory scale devices to manufacturable large-area solar cells that can compete with bulk silicon solar cells and up-and-coming thin-film solar cells will be challenging.

Microfluidic components and systems for rapid (

Microsystems comprising microfluidic networks and miniaturized actuators, transducers, and sensors provide a convenient, revealing, and low-cost means for studying chemical reactions, separation processes such as filtration and extraction, phase changes, mixing, heat and mass transfer, and fluid flow phenomena. For instance, palm-sized plastic cartridges or cassettes (‘chips’) with channels, chambers, manifolds and other components for flow control and fluid actuation can be instrumented with embedded thermocouples and pressure sensors, and operated with small Peltier coolers/heaters and programmable syringe pumps or microrotary pumps. With proper design, the on-chip microfluidic processes can also be imaged with CCD cameras (especially using fluorescent dyes and particles), and infrared thermal cameras for temperature profiling. Such image (including video) capture and processing affords much more data compared to point sensors such as thermocouples and pressure transducers, and can be directly compared with finite element modeling. These systems are effective vehicles for project-based learning in fluid mechanics, heat transfer, chemical reaction engineering, separation processes and other unit operations, process control, and various biotechnical operations such as enzymatic digestion, nucleic acid amplification, and sample fractionation. The chips are made as bonded laminates from patterned acrylic, polycarbonate, thin metal sheet, and many other material types. Students can quickly design (using CAD software such as SolidWorks™), simulate (using FEM programs such as Comsol) microfluidic platforms, that can be rapid prototyped with laser machining, 3D printing, CNC machining, soft lithography, engraving and printed circuit board fabrication methods with a turn-around time of 1 day. The chip is instrumented using LabView™ or an Arduino™ microcontroller for data acquisition and process control. These benchtop or desktop systems make only modest demands on the resources of educational institutions, due to their low cost and safety, and minimal waste generation and reagent consumption. Also, their multidisciplinary nature affords an excellent opportunity for students to integrate their knowledge of CAD, simulation, prototyping, instrumentation and microcontrollers, statistical data analysis, and image processing and analysis. Further, these experiments give students a high level of hands on interaction and visualization of important unit operation processes. We discuss in detail some representative systems for heat exchangers, mixers, chemical reactors, and crystal growth, and their use as educational, project-based modules in the undergraduate engineering curriculum.

Point-of-care (POC) medical diagnostics tests based on instrumented microfluidic chips are instructive and highly-multidisciplinary projects for undergraduate research and Senior Design. Students can apply their knowledge of fluid mechanics, heat transfer, optics, electronics and microcontrollers, materials, prototyping and systems engineering in translating and adapting a laboratory-based test for use in non-traditional venues. We discuss the design, prototyping, and testing of POC lab-on-a-chip (LOC) systems in an educational setting, where undergraduate students develop and demonstrate novel and practical POC tests. This application area serves as an effective gateway to the medical diagnostics field for engineering students, with opportunities for providing sustainable, appropriate, and ‘green’ technology to the developing world where healthcare infrastructure is lacking.

A suite of surface measurement methods are described, assessed and compared for several types of materials of technological interest including silicon for solar cells, machined metal surfaces, and rapid prototyped (e.g., 3d-printed) plastic parts. We describe student laboratory projects for surface roughness characterization using different techniques including depth gauge, stylus profilometer, atomic force microscope (AFM), glossmeter, LED light scattering, laser light scattering, image processing, and wetting angle measurements. This provides instructive case studies for learning concepts of surface characterization and metrology, comparing information gained by different measurement techniques, gauge reproducibility and repeatability, optimizing post-processing in rapid prototyping, and issues for adapting measurements for automated and in-line quality assurance.

Molecular detection determines the presence and quantity of selected nucleic acids associated with pathogens, such as viruses, bacteria, and parasites, as well as a host’s mutant alleles in clinica...

Microfluidic cassettes ("chips") for processing and analysis of clinical specimens and other sample types facilitate point-of-care (POC) immunoassays and nucleic acid based amplification tests. These single-use test chips can be self-contained and made amenable to autonomous operation-reducing or eliminating supporting instrumentation-by incorporating laminated, pliable "pouch" and membrane structures for fluid storage, pumping, mixing, and flow control. Materials and methods for integrating flexible pouch compartments and diaphragm valves into hard plastic (e.g., acrylic and polycarbonate) microfluidic "chips" for reagent storage, fluid actuation, and flow control are described. We review several versions of these pouch chips for immunoassay and nucleic acid amplification tests, and describe related fabrication techniques. These protocols thus offer a "toolbox" of methods for storage, pumping, and flow control functions in microfluidic devices.

The HIV pandemic affects 36.7 million people worldwide, predominantly in resource-poor settings. Nucleic acid-based molecular detection of HIV plays a significant role in antiretroviral treatment monitoring for HIV patients, as well as diagnosis of HIV infection in infants. Currently available molecular diagnostic methods are complex, time-consuming and relatively expensive, thus limiting their use in resource-poor settings. Recent advances in microfluidics technology have made possible low-cost integrated miniaturized devices for molecular detection and quantification of HIV at the point of care. We review recent technical advances in molecular testing of HIV using microfluidic technology, with a focus on assays based on isothermal nucleic acid amplification. Microfluidic components for sample preparation, isothermal amplification and result detection are discussed and compared. We also discuss the challenges and future directions for developing an integrated “sample-to-result” microfluidic platform for HIV molecular detection.

Microfluidic cassettes ("chips") for processing and analysis of clinical specimens and other sample types facilitate point-of-care (POC) immunoassays and nucleic acid based amplification tests. These single-use test chips can be self-contained and made amenable to autonomous operation-reducing or eliminating supporting instrumentation-by incorporating laminated, pliable "pouch" and membrane structures for fluid storage, pumping, mixing, and flow control. Materials and methods for integrating flexible pouch compartments and diaphragm valves into hard plastic (e.g., acrylic and polycarbonate) microfluidic "chips" for reagent storage, fluid actuation, and flow control are described. We review several versions of these pouch chips for immunoassay and nucleic acid amplification tests, and describe related fabrication techniques. These protocols thus offer a "toolbox" of methods for storage, pumping, and flow control functions in microfluidic devices.

We report the design, fabrication, and testing of a microfluidic device for molecular diagnostics that sites lysis, solid-phase extraction of nucleic acids, polymerase chain reaction (PCR) amplification, and real-time fluorescence detection in a single chamber. This streamlined design considerably simplifies the fabrication and operation of chip-based nucleic acid assays for detection of pathogens and other disease markers. A single 25-μL PCR chamber in a plastic chip houses a cellulose-based filter membrane (Whatman FTA®) for extraction of nucleic acids from the sample. Nucleic acids captured on the filter serve as a template for in situ PCR amplification. The single-use (disposable) microfluidics chip mates with a portable instrument that provides double-sided heating of the PCR chamber for rapid thermal cycling, and incorporates, real time fluorescence detection using a low-cost, miniaturized (ESE GmbH) fluorescence reader. We optimized multiple-pass sample loading of the FTA® membrane, vacuum drying of membrane, and membrane wash steps to improve extraction efficiency in a microfluidics format. The chip was tested with samples of Bacillus cereus bacterial culture, and showed a limit of detection of ~103 target cells. The adaptation of this chip to practical microfluidics applications incorporating integrated pouches for storage and fluid actuation, and pre-loading of dry-stored PCR reagents is discussed, along with potential near-term applications.

There is an urgent need for rapid, sensitive, and affordable diagnostics for microbial infections at the point-of-care. Although a number of innovative systems have been reported that transform mobile phones into potential diagnostic tools, the translational challenge to clinical diagnostics remains a significant hurdle to overcome.A smartphone-based real-time loop-mediated isothermal amplification (smaRT-LAMP) system was developed for pathogen ID in urinary sepsis patients. The free, custom-built mobile phone app allows the phone to serve as a stand-alone device for quantitative diagnostics, allowing the determination of genome copy-number of bacterial pathogens in real time.A head-to-head comparative bacterial analysis of urine from sepsis patients revealed that the performance of smaRT-LAMP matched that of clinical diagnostics at the admitting hospital in a fraction of the time (~1 h vs. 18-28 h). Among patients with bacteremic complications of their urinary sepsis, pathogen ID from the urine matched that from the blood - potentially allowing pathogen diagnosis shortly after hospital admission. Additionally, smaRT-LAMP did not exhibit false positives in sepsis patients with clinically negative urine cultures.The smaRT-LAMP system is effective against diverse Gram-negative and -positive pathogens and biological specimens, costs less than $100 US to fabricate (in addition to the smartphone), and is configurable for the simultaneous detection of multiple pathogens. SmaRT-LAMP thus offers the potential to deliver rapid diagnosis and treatment of urinary tract infections and urinary sepsis with a simple test that can be performed at low cost at the point-of-care. FUND: National Institutes of Health, Chan-Zuckerberg Biohub, Bill and Melinda Gates Foundation.

Often, high-sensitivity, point-of-care (POC) clinical tests, such as HIV viral load, require large volumes of plasma. Although centrifuges are ubiquitously used in clinical laboratories to separate plasma from whole blood, centrifugation is generally inappropriate for on-site testing. Suitable alternatives are not readily available to separate the relatively large volumes of plasma from milliliters of blood that may be needed to meet stringent limit-of-detection specifications for low-abundance target molecules. We report on a simple-to-use, low-cost, pump-free, membrane-based, sedimentation-assisted plasma separator capable of separating a relatively large volume of plasma from undiluted whole blood within minutes. This plasma separator consists of an asymmetric, porous, polysulfone membrane housed in a disposable chamber. The separation process takes advantage of both gravitational sedimentation of blood cells and size exclusion-based filtration. The plasma separator demonstrated a "blood in-plasma out" capability, consistently extracting 275 ± 33.5 μL of plasma from 1.8 mL of undiluted whole blood within less than 7 min. The device was used to separate plasma laden with HIV viruses from HIV virus-spiked whole blood with recovery efficiencies of 95.5% ± 3.5%, 88.0% ± 9.5%, and 81.5% ± 12.1% for viral loads of 35,000, 3500, and 350 copies/mL, respectively. The separation process is self-terminating to prevent excessive hemolysis. The HIV-laden plasma was then injected into our custom-made microfluidic chip for nucleic acid testing and was successfully subjected to reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP), demonstrating that the plasma is sufficiently pure to support high-efficiency nucleic acid amplification.