Development of a vitrified CRISPR/Cas12b-based assay for rapid genotyping of SLCO1B1 SNPs without DNA amplification†

Abstract

Two single nucleotide polymorphisms (SNPs) in the human SLCO1B1 gene, c.388A>G (rs2306283) and c.521T>C (rs4149056), are independent determinants of the efficacy and side effects of statin drugs. Multinational clinical guidelines recommend testing for SLCO1B1 genotypes before the initial use of statins. Current SLCO1B1 SNP identification methods, primarily based on quantitative fluorescence PCR, rely on expensive equipment, are time-consuming, and require cold-chain storage for reagents, making them unsuitable for use in resource-limited healthcare settings. In this study, we developed a CRISPR/Cas12b-based amplification-free genotyping technique for SLCO1B1 SNPs. Within 30 minutes of the isothermal reaction, genotyping of the c.388A>G and c.521T>C SNPs in the SLCO1B1 gene can be observed by the naked eyes under blue light. Additionally, maltodextrin was identified as an effective vitrification stabilizer for the CRISPR/Cas12b premix. A low-cost vitrification process was optimized to prepare a glass like solid reagent via room-temperature vacuum drying. The vitrified CRISPR/Cas12b reagent retained approximately 88% of its activity after 30 days of storage at 37 °C, eliminating the need for cold-chain storage and allowing for long-term preservation at room temperature. This vitrified CRISPR/Cas12b based rapid SNP detection technique is especially suitable for genotyping drug metabolism genes in primary healthcare settings, providing effective guidance for precision medicine in clinical practice.