4.1. Materials and reagents
K3Fe(CN)6, K4Fe(CN)6, KCl, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), andN -hydroxysuccinimide (NHS) were purchased from Aladdin Biotechnology Co., Ltd. (Shanghai, China). Carboxylated CdTe/ZnS QDs was purchased from Ruixi Biotechnology Co., Ltd. (Xi’an, China). Phosphate-buffered saline (PBS) buffer (0.1 M, pH 7.4), and 2-(N -morpholino)ethanesulfonic acid (MES) buffer (0.1 M, pH 6.0) were purchased from Phygene Biotechnology Co., Ltd. (Fuzhou, China). Cas12a, 10× Cas12a Reaction Buffer and fluorescein amidite – single-stranded DNA (FAM-ssDNA) reporter were purchased from EZassay Biotechnology Co., Ltd. (Shenzhen, China). A nucleic acid extraction kit (Magnetic Beads Method) was purchased from Zhongyuan Biotechnology Co., Ltd. (Chongqing, China). A PrimeScript™ RT reagent kit was purchased from TaKaRa Biotechnology Co., Ltd. (Dalian, China). Tris(2-carboxyethyl)phosphine hydrochloride (TCEP), ethylenediaminetetraacetic acid (EDTA), and 6-mercaptohexanol (MCH) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China). The construction of plasmids carrying the designed dsDNA template and the synthesis of crRNA, ssDNAs 1, 2, and 3 (Table S1) were performed by Sangon Biotech Co., Ltd. (Shanghai, China).