A universal probe system for low-abundance point mutation detection based on endonuclease IV

Systematic optimization of UCNPs-LFA for Helicobacter pylori nucleic acid detection at point-of-care

Helicobacter pylori (Hp) prevail globally as the primary cause of gastritis, gastric ulcer, and potential gastric cancer, highlighting the need for rapid and precise point-of-care (POC) detection of Hp nucleic acid. Upconversion nanoparticle-based lateral flow assay (UCNPs-LFA) exhibit great potential in POC detection, due to their high optical stability and absence of background fluorescence. However, insufficient sensitivity for nucleic acid detection remains a key challenge. This study systematically optimizes UCNPs-LFA by focusing on target capture, signal transduction, signal separation, and signal analysis, to enhance its detection capabilities for Hp nucleic acid. The optimized UCNPs-LFA platform features a significantly decreased detection limit, a broadened detection range, and high reliability. Results demonstrate that the limit of detection (LOD) is 25 fM, a 105-fold improvement over the initial platform. This systematic optimization strategy is versatile and can be applied to optimize other nanoparticle-based LFAs.

MscI restriction enzyme cooperating recombinase-aided isothermal amplification for the ultrasensitive and rapid detection of low-abundance EGFR mutations on microfluidic chip

The detection of low-abundance mutation genes of the epidermal growth factor receptor (EGFR) exon 21 (EGFR L858R) plays a crucial role in the diagnosis of non-small cell lung cancer (NSCLC), as it enables early cancer detection and facilitates the development of treatment strategies. A detection platform was developed by combining the MscI restriction enzyme with the recombinase-aided isothermal amplification (RAA) technique (MRE-RAA). During the RAA process, "TGG^CCA" site of the wild-type genes was cleaved by the MscI restriction enzyme, while only the low-abundance mutation genes underwent amplification. Notably, when the RAA product was combined with CRISPR-Cas system, the sensitivity of detecting the EGFR L858R mutation increased by up to 1000-fold for addition of the MscI restriction enzyme. This achievement marked the first instance of attaining an analytical sensitivity of 0.001%. Furthermore, a disk-shaped microfluidic chip was developed to automate pretreatment while concurrently analyzing four blood samples. The microfluidic features of the chip include DNA extraction, MRE-RAA, and CRISPR-based detection. The fluorescence signal is employed for detection in the microfluidic chip, which is visible to the naked eye upon exposure to blue light irradiation. Furthermore, this platform has the capability to facilitate early diagnosis for various types of cancer by enabling high-sensitivity detection of low-abundance mutation genes.