Multifunctional Ethyl Violet@NH<sub>2</sub>‑MIL-88B(Fe)\nHybrids: CRISPR-Cas12a-Assisted PEC-FL-CL Triple-Mode Sensitive Detection\nof HPV‑16

The\nmultimode assay based on multiple response mechanisms has received\ngreat attention to effectively improve the accuracy of a sensing platform.\nHowever, multifunctional sensing materials for simultaneously satisfying\nthe multiple-mode detections are still in shortage due to the incompatibility\nof the signal transduction mechanisms in different modes. Here, taking\nhuman papillomavirus 16 (HPV-16) DNA (TDNA) as the model due to its\nimportant role in cervical cancer, a novel multifunctional material,\nethyl violet (EV)@NH<sub>2</sub>-MIL-88B(Fe) (ENM) hybrids, have been\nsuccessfully prepared, which could simultaneously satisfy CRISPR-Cas12a-assisted\nphotoelectrochemical (PEC)-fluorescent (FL)-colorimetric (CL) triple-mode\ndetection of TDNA. Based on the TDNA-induced trans-cleavage ability\nof CRISPR-Cas12a and efficient separation of magnetic beads, ENM was\nobtained from the single-stranded DNA-surrounded streptavidin-modified\nmagnetic beads-ENM (SMB-ssDNA-ENM) and decomposed by pyrophosphate\nto get free EV, 2-aminoterephthalic acid (NH<sub>2</sub>–BDC),\nand Fe<sup>3+</sup>. Thus, TDNA was sensitively detected based on\nthe EV-enhanced PEC signal of SnS<sub>2</sub> nanosheets (PEC mode),\nfluorescent signal of NH<sub>2</sub>–BDC (FL mode), and characteristic\nabsorption peak at about 720 nm of Fe<sup>3+</sup>-induced Prussian\nblue (PB) (CL mode). The designed PEC-FL-CL triple-mode biosensing\nplatform had good performance for the detection of TDNA with a wide\nlinear range (0.1 fM–100 nM) and ultralow detection limits\n(0.07 fM for PEC, 0.03 fM for FL and 0.09 fM for CL). Additionally,\nthe developed PEC-FL-CL triple-mode biosensing platform has great\npotential for applications in early disease diagnosis and bioanalysis,\nas it can be easily extended to other DNA assays through modification\nof the crRNA sequence within the CRISPR-Cas12a system.