An anchored CRISPR/Cas12a system-boosted paper-based microfluidic platform for on-site detection of Streptococcus mutans

The emergence and robust advancement of the CRISPR/Cas system have presented novel opportunities for the development of paper-based microfluidics. In this study, the CRISPR/Cas system is firstly ingeniously integrated into a paper-based platform as an efficient signal amplification component. The Cas12a-crRNA system is integrated with nitrocellulose (NC) membrane to prepare an anchored CRISPR-Cas12a system-boosted paper-based microfluidic device, thereby increasing the local concentration of the CRISPR/Cas12a-crRNA system and enhancing catalytic efficiency. Compared with free CRISPR/Cas12a system, our explored split anchored CRISPR/Cas12a signal amplification component demonstrates a catalytic constant that is 22 times higher and a specificity constant that is 34 times greater. Further, an anchored split CRISPR/Cas12a boosted paper-based microfluidic array (ASCPMA) has been further constructed for the on-site detection of Streptococcus mutans ( S. mutans ) to assess the early risk of oral caries. ASCPMA exhibits a wide linear range from 10 CFU/mL to 10 8  CFU/mL, with a detection limit as low as 2.08 CFU/mL, and it has been successfully applied to test 140 clinical saliva samples. With rapidity, accuracy, and portability, ASCPMA will facilitate early diagnosis and prevention of dental caries.