Fabrication of β-CD/SiO2@rGO/MXenes composite materials with three-dimensional structures for sensitive detection of baicalin in Chinese medicine

Abstract

Baicalin is a principal component of traditional Chinese medicine and plays a crucial role in treating conditions such as arthritis, respiratory tract infections, chronic and acute hepatitis, and tumors. Graphene oxide is bonded to silicon dioxide (SiO₂) through covalent bonds or hydrogen bonds and then reduced to SiO₂@rGO through hydrazine hydrate to solve the problem of easy accumulation of SiO₂ and improve the conductivity of the material. Next, β-cyclodextrin (β-CD) self-assembles on SiO₂@rGO to form a stable inclusion complex. The hydrophobic inner cavity of β-CD can effectively accommodate various guest molecules to form inclusion complexes, enhancing molecular recognition and detection capabilities. Finally, β-CD/SiO₂@rGO is bridged and surface-loaded between clay-like Ti₃C₂T_x (MXenes) nanosheets through electrostatic interactions to form a stable three-dimensional composite material. It is precisely because of MXenes, due to their unique layered microstructure, excellent conductivity, and extensive hydrophilic surface area, that they are conducive to self-assembly or embedding nanoparticles in aqueous solution. The composite was characterized via X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. Under optimized conditions, the electrochemical sensor constructed from this composite exhibited a broad detection range (0.008–10 μM) and a low detection limit (0.191 nM) for baicalin. In comparison to existing methods for detecting baicalin, this approach demonstrates strong anti-interference capabilities and stability. It can efficiently, sensitively, and accurately quantify baicalin in Chinese patent medicine samples, including Scutellaria baicalensis root, Shuanghuanglian oral liquid, and Bear Bile Scutellaria baicalensis eye drops, achieving a satisfactory recovery rate. This study introduces a novel approach for the electrochemical detection of baicalin.