A label-free PEC aptasensor platform based on g-C₃N₄/BiVO₄ heterojunction for tetracycline detection in food analysis

A simple low-cost label-free photoelectrochemical (PEC) biosensing platform based on red blood cell shaped BiVO₄ modified g-C₃N₄ was designed for tetracycline detection under room temperature. The prepared g-C₃N₄/BiVO₄ heterojunction not only demonstrated a high surface area, excellent physicochemical stability and favorable PEC activity, but also can be employed as nanostructure support for aptamers to construct a visible-light-driven PEC aptasensor due to rich π-π accumulation sites. More importantly, the proposed PEC aptasensor showed a favorable linear toward tetracycline in the range from 5 × 10^-9 to 2 × 10^-7 M with a detection limit of 1.6 nM, which well covered the Food Standards Testing requirements. Practical food sample analysis further revealed the accuracy and feasibility of the g-C₃N₄/BiVO₄ heterostructure based PEC platform. It is expected that such a label-free and cost-effective PEC strategy should act as a promising candidate for tetracycline determination in food quality control and supervision.