Brightness and stable dye-doped fluorescent polystyrene microspheres: quantitative lateral flow immunoassay detecting serum amyloid A

Abstract

Difluoroboron is a fundamental molecular building block that enables the development of numerous highly-bright fluorophores for biosensing and imaging. However, the poor stability and limited brightness in aqueous solutions are long-standing and unsolved issues in difluoroboron-based fluorophores, which significantly limits their widespread biosensing applicability. Herein, we report a generalizable strategy, dye-doped fluorescent polystyrene microspheres, for innovating a local hydrophobic microenvironment to “protect” difluoroboron curcuminoid from the proximity of water and reactive oxygen species. This strategy demonstrates a breakthrough in chemical and photo- stability and brightness of difluoroboron-based fluorophores in water solutions, making it ideally suitable for point-of-care testing. By using the dye-doped fluorescent polystyrene microspheres, lateral flow immunoassay results highlight that a wide linear range, low limit of detection value, good intra-assay and inter-assay, which serve as an efficient tool for serum amyloid A detection in human serum samples.