Tailored protein corona behavior in titanium dioxide nanosheet fluorescence biosensor for protein quantification assays

The spontaneous adsorption of proteins onto nanoparticles, known as the protein corona, provides a unique perspective for designing protein-sensing biosensors. This study proposes a tailored protein corona method mediated by Tween-20 and develops a reverse-capture approach for protein quantification assays. The protein-coated microplate captures titanium dioxide nanosheets (TiO 2 -NS) in a phosphate buffer containing Tween-20 and generates fluorescence signals via the photocatalytic reduction of resazurin to resorufin, thereby indicating the amount of protein. The linear range of the current assay was 0.5–5 ng/mL, and the limit of detection (LOD) was 0.28 ng/mL, which is 100–1000 times more sensitive than the classical colorimetric methods. This method is suitable for the determination of proteins in artificial urine and has broad potential for practical applications.