3. Conclusions
In this study, a novel automated robot-driven PEC biosensing platform, integrating a CRISPR/Cas12a system and PEC analysis, facilitated rapid, ultrasensitive, highly specific detection of biological loads in sewage. By harnessing the remarkable conductivity and extensive specific surface area offered by vertical graphene, the excellent photoelectric characteristics of CdTe/ZnS QDs, and the high specificity and efficient trans-cleavage activity of the Cas12a–Cas system, the developed PEC biosensor exhibited outstanding analytical capabilities. The biosensor demonstrated an extensive linear range spanning from 1.0 aM to 1.0 nM, a remarkable lower detection limit of 2.93×102 zM, and exceptional selectivity at the level of single-base mutation recognition. Furthermore, the Shennong-1 robot was employed to automate sewage sampling, enrichment, concentration, nucleic acid extraction, and reverse transcription, expediting the analysis of Omicron BA.5 in sewage. This innovative robot- driven photoelectrochemical biosensing platform promises swift, ultrasensitive, and highly precise detection of Omicron BA.5, making it an excellent candidate for future applications of sewage monitoring for biological loads.