Enhancing Loop-Mediated Isothermal Amplification through Nonpowered Nanoelectric Preconcentration.

The global threat posed by the COVID-19 pandemic has catalyzed the development of point-of-care (POC) molecular diagnostics. While loop-mediated isothermal amplification (LAMP) stands out as a promising technique among FDA-approved methods, it is occasionally susceptible to a high risk of false positives due to nonspecific amplification of a primer dimer. In this work, we report an enhancing LAMP technique in terms of assay sensitivity and reliability through streamlined integration with a nonpowered nanoelectric preconcentration (NPP).

Centrifugation-Assisted Three-Dimensional Printing of Devices Embedded with Fully Enclosed Microchannels.

The challenges in reliably removing the sacrificial material from fully enclosed microfluidic channels hinder the use of three-dimensional (3D) printing to create microfluidic devices with intricate geometries. With advances in printer resolution, the etching of sacrificial materials from increasingly smaller channels is poised to be a bottleneck using the existing techniques. In this study, we introduce a microfabrication approach that utilizes centrifugation to effortlessly and efficiently remove the sacrificial materials from 3D-printed microfluidic devices with densely packed microfeatures.

Chemically Amplified Multiplex Detection of SARS-CoV-2 and Influenza A and B Viruses via Paint-Programmed Lateral Flow Assays.

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) continues to threaten lives by evolving into new variants with greater transmissibility. Although lateral flow assays (LFAs) are widely used to self-test for coronavirus disease 2019 (COVID-19), these tests suffer from low sensitivity leading to a high rate of false negative results. In this work, a multiplexed lateral flow assay is reported for the detection of SARS-CoV-2 and influenza A and B viruses in human saliva with a built-in chemical amplification of the colorimetric signal for enhanced sensitivity.

Paper-based multi-well depletion ELISA.

Enzyme-linked immunosorbent assay (ELISA) is widely employed for detecting target molecules in bioassays including the serological assays that measure specific antibody titers. However, ELISA tests are inherently limited to centralized laboratories staffed with trained personnel as the assay workflow requires multiple steps to be performed in a specific sequence. Here, we report a dipstick ELISA test that automates this otherwise laborious process and reports the titer of a target molecule in a digital manner without the need for an external instrument or operator.

High throughput, label-free isolation of circulating tumor cell clusters in meshed microwells.

Extremely rare circulating tumor cell (CTC) clusters are both increasingly appreciated as highly metastatic precursors and virtually unexplored. Technologies are primarily designed to detect single CTCs and often fail to account for the fragility of clusters or to leverage cluster-specific markers for higher sensitivity. Meanwhile, the few technologies targeting CTC clusters lack scalability.

Capillary flow control in lateral flow assays via delaminating timers.

Lateral flow assays (LFAs) use capillary flow of liquids for simple detection of analytes. While useful for spontaneously wicking samples, the capillary flow inherently limits performing complex reactions that require timely application of multiple solutions. Here, we introduce a technique to control capillary flow on paper by imprinting roadblocks on the flow path with water-insoluble ink and using the gradual formation of a void between a wetted paper and a sheath polymer tape to create timers.

Point-of-Care Toolkit for Multiplex Molecular Diagnosis of SARS-CoV-2 and Influenza A and B Viruses.

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is still spreading around the globe causing immense public health and socioeconomic problems. As the infection can progress with mild symptoms that can be misinterpreted as the flu, self-testing methods that can positively identify SARS-CoV-2 are needed to effectively track and prevent the transmission of the virus. In this work, we report a point-of-care toolkit for multiplex molecular diagnosis of SARS-CoV-2 and influenza A and B viruses in saliva samples.

Origami paper-based sample preconcentration using sequentially driven ion concentration polarization.

Ion concentration polarization (ICP) is one of the preconcentration techniques which can acquire a high preconcentration factor. Still, the main hurdles of ICP are its instability and low efficiency under physiological conditions with high ionic strength and abundant biomolecules. Here, we suggested a sequentially driven ICP process, which enhanced the electrokinetic force required for preconcentration, enabling enrichment of highly ionic raw samples without increasing the electric field.

Highly efficient and scalable biomarker preconcentrator based on nanoelectrokinetics.

Micro/nanofluidics are excellent candidates for biological sample preparation. However, the limited process volume in micro/nanofluidics is the main hurdle limiting their practical applications. To date, most micro/nanofluidics have processed sample volumes of several microliters and have rarely been used to handle large-volume samples.

Paper-Based Preconcentration and Isolation of Microvesicles and Exosomes.

Microvesicles and exosomes are small membranous vesicles released to the extracellular environment and circulated throughout the body. Because they contain various parental cell-derived biomolecules such as DNA, mRNA, miRNA, proteins, and lipids, their enrichment and isolation are critical steps for their exploitation as potential biomarkers for clinical applications. However, conventional isolation methods (e.

Origami-paper-based device for microvesicle/exosome preconcentration and isolation.

Microvesicles and exosomes are promising liquid biopsy biomarkers. However, conventional isolation techniques damage and contaminate the biomarkers. We developed an origami-paper-based device for effective isolation of biomarkers with less damage and in fewer steps.

Combinatorial Immunophenotyping of Cell Populations with an Electronic Antibody Microarray.

Immunophenotyping is widely used to characterize cell populations in basic research and to diagnose diseases from surface biomarkers in the clinic. This process usually requires complex instruments such as flow cytometers or fluorescence microscopes, which are typically housed in centralized laboratories. Microfluidics are combined with an integrated electrical sensor network to create an antibody microarray for label-free cell immunophenotyping against multiple antigens.

Electrokinetic Size-Based Spatial Separation of Micro/Nanospheres Using Paper-Based 3D Origami Preconcentrator.

Sample preparation steps (e.g., preconcentration and separation) are key to enhancing sensitivity and reliability in biomedical and analytical chemistry.

Battery operated preconcentration-assisted lateral flow assay.

Paper-based analytical devices (e.g. lateral flow assays) are highly advantageous as portable diagnostic systems owing to their low costs and ease of use.

Simple and Highly Sensitive Molecular Diagnosis of Zika Virus by Lateral Flow Assays.

We have developed a simple, user-friendly, and highly sensitive Zika virus (ZIKV) detection method by incorporating optimized reverse transcription loop-mediated isothermal amplification (RT-LAMP) and a lateral flow assay (LFA). The optimized RT-LAMP reaction was carried out using Bst 3.0 polymerase, which has robust and fast isothermal amplification performance even in the presence of high concentrations of inhibitors; this permitted the amplification of ZIKV RNA in pure water and human whole blood.

Low-cost and facile fabrication of a paper-based capillary electrophoresis microdevice for pathogen detection.

This paper describes the development of a novel paper-based capillary electrophoresis (pCE) microdevice using mineral paper, which is durable, oil and tear resistant, and waterproof. The pCE device is inexpensive (~$1.6 per device for materials), simple to fabricate, lightweight, and disposable, so it is more adequate for point-of-care (POC) pathogen diagnostics than a conventional CE device made of glass, quartz, silicon or polymer.

An integrated direct loop-mediated isothermal amplification microdevice incorporated with an immunochromatographic strip for bacteria detection in human whole blood and milk without a sample preparation step.

We have developed an integrated direct loop-mediated isothermal amplification (Direct LAMP) microdevice incorporated with an immunochromatographic strip (ICS) to identify bacteria contaminated in real samples. The Direct LAMP is a novel isothermal DNA amplification technique which does not require thermal cycling steps as well as any sample preparation steps such as cell lysis and DNA extraction for amplifying specific target genes. In addition, the resultant amplicons were colorimetrically detected on the ICS, thereby enabling the entire genetic analysis process to be simplified.

Total integrated slidable and valveless solid phase extraction-polymerase chain reaction-capillary electrophoresis microdevice for mini Y chromosome short tandem repeat genotyping.

A fully integrated slidable and valveless microsystem, which performs solid phase DNA extraction (SPE), micro-polymerase chain reaction (μPCR) and micro-capillary electrophoresis (μCE) coupled with a portable genetic analyser, has been developed for forensic genotyping. The use of a slidable chip, in which a 1 μL-volume of the PCR chamber was patterned at the center, does not necessitate any microvalves and tubing systems for fluidic control. The functional micro-units of SPE, μPCR, and μCE were fabricated on a single glass wafer by conventional photolithography, and the integrated microdevice consists of three layers: from top to bottom, a slidable chip, a channel wafer in which a SPE chamber, a mixing microchannel, and a CE microchannel were fabricated, and a Ti/Pt resistance temperature detector (RTD) wafer.

Correction: An integrated slidable and valveless microdevice with solid phase extraction, polymerase chain reaction, and immunochromatographic strip parts for multiplex colorimetric pathogen detection.

Correction for 'An integrated slidable and valveless microdevice with solid phase extraction, polymerase chain reaction, and immunochromatographic strip parts for multiplex colorimetric pathogen detection' by Yong Tae Kim et al., Lab Chip, 2015, 15, 4148-4155.

An integrated slidable and valveless microdevice with solid phase extraction, polymerase chain reaction, and immunochromatographic strip parts for multiplex colorimetric pathogen detection.

A total integrated genetic analysis microsystem was developed, which consisted of solid phase extraction (SPE), polymerase chain reaction (PCR), and immunochromatographic strip (ICS) parts for multiplex colorimetric detection of pathogenic Staphylococcus aureus (S. aureus) and Escherichia coli O157:H7 (E. coli O157:H7) on a portable genetic analyzer.