Since the coronavirus disease 2019 (COVID-19) pandemic, isothermal amplification techniques have attracted attention due to their higher sensitivity and specificity, compared with immunoassays, and their potential application for point-of-care testing (POCT). A requirement of isothermal amplification-based POCT kits is the inclusion of a heating source with an electrical power supply. We developed an amplification-based rapid kit, which is a portable and naked eye-detectable reverse transcriptase (RT)-recombinase polymerase amplification (RPA) kit. The rapid RT-RPA kit consists of a flow-controllable paper chip, a nickel-chromium (NiCr)-based Joule-heating thin film, and a small-sized portable battery. We found that the Joule-heating thin film, powered by a lithium-ion battery (7.5 g, 20 mm × 35 mm size), was able to maintain the required temperature for the RPA reaction. After the RPA reaction, which takes approximately 20 min, the flow-controllable paper chip automatically enabled visualization of the amplicon by time-delayed release of gold nanoparticle-based optical probes. Using this system, we successfully detected severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at levels as low as 10 copies μL, within 30 min.
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http://dx.doi.org/10.1016/j.talanta.2024.127327 | DOI Listing |
Sci Adv
January 2025
Thomas Lord Department of Mechanical Engineering and Materials, Duke University, Durham, NC 27708, USA.
Precise and rapid disease detection is critical for controlling infectious diseases like COVID-19. Current technologies struggle to simultaneously identify viral RNAs and host immune antibodies due to limited integration of sample preparation and detection. Here, we present acoustofluidic integrated molecular diagnostics (AIMDx) on a chip, a platform enabling high-speed, sensitive detection of viral immunoglobulins [immunoglobulin A (IgA), IgG, and IgM] and nucleic acids.
View Article and Find Full Text PDFAnal Chem
January 2025
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
Multiplex digital nucleic acid analysis (NAA) allows the precise quantification of multiple target nucleic acids with single-molecule sensitivity, making it highly appealing for life science research and clinical diagnostics. Nucleic acid-guided endonucleases, such as CRISPR, have demonstrated great potential in digital NAA. However, performing multiplex digital NAA with an endonuclease remains challenging.
View Article and Find Full Text PDFBMC Infect Dis
January 2025
Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, 21702, United States of America.
Background: Point of need diagnostics provide efficient testing capability for remote or austere locations, decreasing the time to answer by minimizing travel or sample transport requirements. Loop-mediated isothermal amplification (LAMP) is an appealing technology for point-of-need diagnostics due to its rapid analysis time and minimal instrumentation requirements.
Methods: Here, we designed and optimized nine LAMP assays that are sensitive and specific to targeted bacterial select agents including Bacillus anthracis, Francisella tularensis, Yersinia pestis, and Brucella spp.
Mikrochim Acta
January 2025
Beijing Key Laboratory for Separation and Analysis in Biomedicine and Pharmaceuticals, School of Medical Technology, Beijing Institute of Technology, Beijing, 100081, China.
A point-of-care testing (POCT) assay based on commercial HCG strip was proposed for miRNA21 detection by integrating RCA-HCR cascaded isothermal amplification with CRISPR/Cas12a. Three modules were integrated in the proposed platform: target amplification module composed of rolling circle amplification (RCA) cascaded with hybridization chain reaction (HCR), signal transduction module composed of CRISPR/Cas12a combined with HCG-agarose gel beads probes, and signal readout module composed of commercial HCG strips. The proposed RCA-HCR-CRISPR/Cas12a-HCG strip assay for miRNA21 detection had high sensitivity, and the limit of detection was as low as 37 fM.
View Article and Find Full Text PDFNat Chem Biol
January 2025
Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA.
Cell-free systems are powerful synthetic biology technologies that can recapitulate gene expression and sensing without the complications of living cells. Cell-free systems can perform more advanced functions when genetic circuits are incorporated. Here we expand cell-free biosensing by engineering a highly specific isothermal amplification circuit called polymerase strand recycling (PSR), which leverages T7 RNA polymerase off-target transcription to recycle nucleic acid inputs within DNA strand displacement circuits.
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