Enzyme-Free Immunosorbent Assay of Prostate Specific Antigen Amplified by Releasing pH Indicator Molecules Entrapped in Mesoporous Silica Nanoparticles

• DOI: 10.1021/acs.analchem.8b02019
• Publication Date: 2018-06-19T10:15:11Z
• Authors: Fengying Shao; Lianhua Zhang; Lei Jiao; Xiaoying Wang; Luyang Miao; He Li; Feimeng Zhou
• Keywords: Glutamate carboxypeptidase II

An enzyme-free titer plate-based colorimetric assay utilizing functionalized mesoporous silica nanoparticles (MSNs) entrapping pH-indicator molecules has been developed. Pores in the were with phenyltrimethyloxysilane so that pH indicator (thymolphthalein or TP present case) can be tightly entrapped through π–π conjugation. To detect prostate specific antigen (PSA), TP-containing MSNs coated polyethylenimine (PEI), which favors attachment of negatively charged secondary anti-PSA antibody. The thymolphthalein readily released from pores a simple addition alkaline solution. resultant bifunctional used for signal-amplified detection PSA captured by primary antibody preimmobilized wells plate. Our method possesses wide dynamic range (0.5 to 8000 pg/mL) wherein adsorption obeys modified Langmuir isotherm. A limit (LOD) down as low 0.36 pg/mL attained. Owing size uniformity and obviation enzyme employed enzyme-linked immunosorbent (ELISA), excellent reproducibility (RSD = 1.12%) was achieved. selective human serum samples demonstrates amenability our important biomarkers complex biological samples, whereas performance plate ensures high throughput obviates use expensive instruments. Both these features are prerequisites clinical settings great number need analyzed timely fashion.