We recently reported an exciting work about the application of a specifically designed chimeric DNA/RNA hairpins to facilitate nucleic acid biosening in a SERS system. It has been discovered that the large protein, CRISPR-Cas12a, is difficult to approach the nanocluster gap or nanomaterial surface due to their strong steric hindrance. Our DNA/RNA hairpin can be destabilized by the activated CRISPR-Cas12a in the presence of target DNA (e.g., SARS-CoV-2 cDNA) to liberate a large amount of complementary RNA, that can replace DNA from gold nanocluster via toehold strand mediated reaction to disassemble the gold nanocluster. This disassembly effectively removes SERS hot spot, thereby formulating a ultrasensitive "ON-OFF" SERS biosensor. This work has been published in Theranostics (MEDICINE, RESEARCH & EXPERIMENTAL Q1)! Website: https://www.thno.org/v12p5914.htm