Polydopamine-enhanced vertically-ordered mesoporous silica film anti-fouling electrochemical aptasensor for indicator-free Vibrio parahaemolyticus discrimination using stable inherent Au signal

Vertically-ordered mesoporous silica film (VMSF) has proven to be an effective anti-interference and anti-fouling layer in the field of analysis. However, because VMSF is not stable enough in complex samples, its application in sensing field is limited. We herein use mussel-inspired multi-functional agent polydopamine (PDA) to enhance the stability of VMSF on electrode. Owing to the amino-functionalized VMSF combined with amino groups on PDA, superhydrophilicity was achieved which was proved to enhance excellent anti-fouling property. In addition, the electrodeposition of Au nanoparticles (AuNP) in the nanochannel of VMSF serving as an internal electrochemical signal shows excellent electrochemical signal stability, which provides a prerequisite for maintaining the further detection accuracy in complex samples. Finally, we validated the detection performance of the anti-fouling sensing strategy using a foodborne pathogen, Vibrio parahaemolyticus (VP), as a model target. Specifically, the aptamer was modified by covalent bond on the PDA-integrated VMSF interface surface for the recognition of VP. Using shrimp homogenate as a real sample, the anti-fouling detection performance of the aptasensor was verified. The linear range of VP detection in real samples was 103-107 CFU/mL, and the detection limit was 103 CFU/mL. The results show that the anti-fouling aptasensor has excellent anti-interference and stability. It is worth emphasizing that this strategy (using inherent Au signal) enables rapid electrochemical analysis of VP without outer indicators, greatly reducing the difficulty of constructing an electrochemical VP detection strategy.