title: Cost-effective and sensitive colorimetric immunosensing using an iron oxide-to-Prussian blue nanoparticle conversion strategy.
abstract: The development of new sensitive, cost-effective and user-friendly colorimetric bioassays is in increasing demand to meet the requirement of modern clinical diagnostics and field detection. Herein, a novel iron oxide-to-Prussian blue (PB) nanoparticle (NP) conversion strategy was developed and applied to sensitive colorimetric immunosensing of cancer biomarkers. In a typical sandwich-type immunosensing system, the captured spherical antibody-conjugated iron oxide NPs were transformed into cubic PB NPs, which exhibited a highly visible blue color with high molar extinction coefficients. Hence, a new colorimetric immunosensing strategy was developed as a result of this low cost and simple transformation process. Without the aid of any complex nanoparticle stabilizing ligands and signal amplification processes, prostate-specific antigen as a model analyte can be detected at a concentration as low as 1.0 ng mL(-1) by the naked eye with good reliability for detection of real human serum samples. This is the first attempt to develop and apply the iron oxide-to-PB NP colorimetric conversion strategy for immunosensing, and shows great promise for the development of new sensitive, cost-effective and user-friendly colorimetric bioassays in various bioanalytical applications, especially in low-resource settings.
authors.affiliation: Department of Chemistry, University of Texas at El Paso, 500 West University Ave, El Paso, Texas 79968, USA. xli4@utep.edu.
authors.forename: Guanglei
authors.initials: G
authors.lastname: Fu
authors.forename: Sharma T
authors.initials: ST
authors.lastname: Sanjay
authors.forename: XiuJun
authors.initials: X
authors.lastname: Li
mesh_terms: D003124:Colorimetry; D005290:Ferric Compounds / Q000737:chemistry*; D005295:Ferrocyanides / Q000737:chemistry*; D006046:Gold; D006801:Humans; D007118:Immunoassay; D008297:Male; D053758:Nanoparticles; D017430:Prostate-Specific Antigen / Q000097:blood; D015203:Reproducibility of Results
chemical_list: D005290:Ferric Compounds; D005295:Ferrocyanides; C000499:ferric oxide; D006046:Gold; D017430:Prostate-Specific Antigen; C000170:ferric ferrocyanide