Advances in nucleic acid amplification techniques (NAATs): COVID-19 point-of-care diagnostics as an example

Achieving superhigh sensitivity is the ultimate goal for bio-detection in modern analytical science and life science. Among variable signal amplification strategies, nucleic acid amplification technologies are revolutionizing the field of bio-detection, providing greater possibilities in novel diagnosis achieving high efficiency, specificity, and cost-effectiveness. Nucleic acid amplification techniques (NAATs), such as Polymerase Chain Reaction (PCR), Rolling Circle Amplification (RCA), Loop-Mediated Isothermal Amplification (LAMP), Recombinase Polymerase Amplification (RPA), CRISPR-related amplification, and others are dominating methods employed in research and clinical settings. They each provide distinctively unique features that can offer desirable performance in terms of sensitivity, specificity, simplicity, stability, and cost. NAATs are in unmet demand in molecular diagnosis, especially in point-of-care scenario. This review will discuss the principles and recent advancements of each NAAT, respectively, revealing their strengths and challenges in achieving rapid and accurate bio-detection with a focus on point-of-care diagnosis. Furthermore, this review will explore the application of each of the technologies through the contemporary COVID-19 pandemic, analyzing their ability in point-of-care diagnosis of the COVID-19 with high sensitivity to emphasize significance of developing NAATs based methods in battling COVID-19. Finally, advantages and potentials of each NAAT in enhancements of sensitivity and specificity in bio-detection from bench side to the bedside will be discussed, aiming for full exploitation of capability of each NAAT. This review will provide novel aspects in the selection and combination of usages of various NAATs based on their distinctive characteristics and limitations. A possible advancing direction of future accurate POCT is also proposed.