The smartphone-assisted ultrasensitive colorimetric aptasensor based on DNA-encoded porous Ti3C2 nanozyme (Apt-P-Ti3C2) was exploited for real-time detection of OA. Porous Ti3C2 (P-Ti3C2) MXene with outstanding peroxidase-like activities were crafted using microwave combustion, facilitating the efficient catalysis of chromogenic substrate oxidation by H2O2. The integration of a considerable number of unsaturated Ti center edges and residual Mn2+ within the single-layer porous Ti3C2 framework augmented the adsorption capacity of DNA aptamer, thereby yielding a heightened catalytic efficacy of P-Ti3C2 nanoparticles. The enhanced catalytic activity of P-Ti3C2 can be partially diminished through specific recognition of OA. Concurrently, a smartphone platform was integrated for signal reading based on the colorimetric sensing strategy. The smartphone-based biosensor exhibited a reliable and ultrasensitive capability for OA detection with the detection limit of 0.38 ng·mL-1. It is anticipated that the developed smartphone-based biosensing platform can provide a prospective ultrasensitive detection method for marine algal toxin in food analysis.
Keywords: Colorimetric sensor; MXene; Nanozyme; Okadaic acid; Smartphone.
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