CRISPR-cas12a mediated SERS lateral flow assay for amplification-free detection of double-stranded DNA and single-base mutation

Lateral flow assay (LFA) is user-friendly diagnostic tools but suffering limitations in poorer sensitivities and specificities especially for double-stranded DNA and single-base mutation quantification. Here, to improve the sensitivity and specificity for the LFA based nucleic acid detection, CRISPR-Cas12a mediated Surface enhanced Raman scattering (SERS) LFA was developed. By combination of ultra-sensitive SERS tags and target-specific signal amplification ability of CRISPR-Cas12a, HIV-1 dsDNA can be directly quantified with a LOD of 0.3 fM without any pre-amplification steps, which is almost 4 orders of magnitude lower than that of traditional colorimetric LFA methods. The whole detection process can be finished less than 1 h. Moreover, based on the target specificity of Cas12a, HIV-1 single-based drug resistance mutation (M184V) can be recognized as low as 0.01%. The HIV-1 dsDNA can also be successfully detected in serum samples with good comparable of that in buffer setting. Therefore, the simple and inexpensive paper-based CRISPR-SERS strip has great potential for point-of-care testing (POCT) of nucleic acid targets especially in resource-poor or non-laboratory environments.

Automated summary

By combining CRISPR-Cas12a and SERS technology, the sensitivity and specificity of LFA nucleic acid detection have been improved, allowing for direct quantification of HIV-1 dsDNA in less than 1 hour and recognition of HIV-1 single-base drug resistance mutations. This paper-based CRISPR-SERS strip has great potential for point-of-care testing in resource-poor or non-laboratory environments.