A CRISPR electrochemical biosensing system (E-CRISPR) for detection of analytes includes a disposable, micro-fabricated three-electrode sensor that includes a working electrode, a counter electrode, a reference electrode, and a nonspecific ssDNA reporter with an electrochemical tag for signal transduction tethered to a surface of the working electrode; and a Cas12a-crRNA duplex that is designed to specifically recognize and cleave target nucleic acid strand based on the protospacer adjacent motif (PAM) sequence of the target and crRNA sequence, wherein the PAM recognition depends on specific 5′ TTTN nucleic acid sequence located at an opposite strand of a recognition strand, and wherein only upon the recognition of the PAM sequence by the Cas protein, the Cas protein, acting as a DNA helicase, unwinds the target DNA.