Silica-encapsulated quantum dots for highly efficient and stable fluorescence immunoassay of C-reactive protein

In this study, we presented a new coating regulation of silica by the reverse microemulsion method to obtain biocompatible high quality silica-encapsulated quantum dot (QD). The hydrophobic CdSe/ZnS QDs were coated with silica successfully and demonstrated good photostability and thermal stability and high fluorescent intensity. The corresponding silica-encapsulated QDs-antibody probes were used to detect C-reactive protein (CRP) with quantum dot-labeled immunosorbent assay (QLISA). Only micro dosage of probes was required due to good antibody-antigen combination in optimized buffer environment. The assay results are comparable to commercial assay kits with a wide analytical range of 1-1000 ng/mL, a low limit of detection of 0.76 ng/mL, and good recovery rates of 87.31–105.48%. The convenience and cost effective aspects of this silica-encapsulated QDs immunosorbent assay motivate future development of in vitro diagnostic kits.