In Situ growth of high-crystallinity MOF@CTF core-shell hybrid heterostructures and their application in photoelectrochemical sensing of vancomycin

Vancomycin is a first-line drug for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant bacterial infections. It is of great significance to develop rapid detection methods for vancomycin in different matrices. In this work, a novel method for the in-situ preparation of MOF@CTF core-shell hybrid heterogeneous structures was proposed and applied to the photoelectrochemical detection of vancomycin. The insolubility of the imine precursor structure in homogeneous solvents and the Lewis acidic centers in the MOF structure induced the initial arrangement of CTF on the surface of PCN-224. By encapsulating a layer of highly crystalline CTF structure onto the initial morphology of PCN-224, a MOF@CTF heterogeneous structure was formed. Importantly, the introduction of anthracene-based electron-donating groups into the CTF structure and the formation of a donor-acceptor system with triazine rings enhanced the photoconversion efficiency of the heterogeneous structure by establishing a continuous separated built-in electric field within the core-shell structure. The successful in-situ synthesis of the core-shell hybrid heterogeneous structure was confirmed through microscopic morphology, PXRD, XPS, and FT-IR. Furthermore, investigations into the semiconductor properties of the heterogeneous structure, including semiconductor type, bandgap, and photo-voltage, were conducted. Results showed that the heterogeneous structure exhibited a doubled photocurrent density compared to the original PCN-224. Additionally, a molecularly imprinted photoelectrochemical sensor (MIPECS) for vancomycin was constructed. Under optimized conditions, the sensor demonstrated a superior concentration response range (0.1 nM - 1 μM) and detection limit (0.031 nM, 3σ/S, n = 11). Simultaneously, the potential applicability of the sensor in animal-derived foods, serum, and environmental water samples was evaluated, yielding satisfactory results.