▎ 摘　　要

NOVELTY - Nucleic acid detection system comprises a detection clustered regularly interspaced short palindromic repeats (CRISPR) system comprising an effector protein and one or more guide nucleic acid strands designed to bind to corresponding target nucleic acid molecules, an effector nucleic acid strand, a detector nucleic acid strand substantially complementary to the effector nucleic acid strand and conjugated with one electroactive label, an electrode comprising a conductive surface, and a nanocomposite coating comprising a mixture of a conducting element and a denatured proteinaceous material coated on conductive surface. USE - Nucleic acid detection system used in a kit and composition for detecting a target nucleic acid (all claimed) to screen environmental samples (air, water, surfaces, food, etc.) for the presence of microbial contamination. ADVANTAGE - The nucleic acid detection system enables affinity-based electrochemical biosensing in complex biological fluids, promotes the formation of a CRISPR complex, is rapid, sensitive, low cost, portable, results are readily interfaced with machine, and it does not require trained user and specialized facilities. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for detecting a nucleic acid, which involves contacting a target nucleic acid with a detection CRISPR system, where the CRISPR detection system comprises an effector protein and one or more guide nucleic acid strands designed to bind to or hybridize with the target nucleic acid molecules, contacting the CRISPR detection system with an electrode, where the electrode comprises a conductive surface, nanocomposite coating comprising a mixture of a conducting element and a denatured proteinaceous material coated on conductive surface, effector nucleic acid strand immobilized on the conductive surface, contacting the electrode with a detector nucleic acid strand, where the detector nucleic acid stand is substantially complementary to the effector nucleic acid strand and is conjugated with one electroactive label, and applying a voltage to the electrode and measuring a current generated from electrode; and (2) a kit and composition, which comprises the nucleic acid detection system.