Abstract
An indirect immunoassay for detecting antigen was developed. It was based on fluorescence resonance energy transfer (FRET) and quenching of gold nanoparticles. Bovine serum albumin (BSA) was chosen as model antigen. Fluorescein isothiocyanate (FITC) was attached to anti-BSA antibody (anti-BSA–FITC) as FRET donor, while BSA was conjugated to gold nanoparticles (GNPs–BSA) as FRET acceptor. The formation of anti-BSA–BSA immunocomplex resulted in the FRET between anti-BSA–FITC and GNPs–BSA. Thus, the fluorescence of FRET donor was quenched, and the decreasing fluorescence intensity responded linearly to the concentration of acceptor within the linear range. The concentration of BSA we obtained according to the stoichiometric ratio between BSA and GNPs. Following this approach, we were able to specifically detect BSA. The detection limit for BSA was 0.5 nM and the linear range of the assay was 2.9 - 43.5 nM. It had been successfully applied to specific detection of BSA in serum samples.
Highlights
Over the past few years, nanoprobes have attracted considerable attention in bioassays, and have been exploited in biodetection, biolabeling and biosensor development [1,2,3]
The fluorescence resonance energy transfer (FRET) acceptor was prepared with the same ratio as Bovine serum albumin (BSA) to Gold nanoparticles (GNPs) described above
We have demonstrated an indirect immunoassay based on fluorescence resonance energy transfer
Summary
Over the past few years, nanoprobes have attracted considerable attention in bioassays, and have been exploited in biodetection, biolabeling and biosensor development [1,2,3]. Gold nanoparticles (GNPs) have been of great interest because of their high extinction coefficient and broad absorption spectrum in visible region which is overlapped with the emission wavelength of usual FRET donor. Both theoretical calculations and experimental studies have well demonstrated that GNPs are a kind of “superquencher” which can quench the fluorescence of a range of dyes with extraordinarily high efficiency [9]. Based on this superquenching effect, GNPs have been successfully served as acceptor in FRET. Yang et al have attempted to employ two FRET assembles in one system, in which luminescent CdTe QDs as FRET donors and GNPs serving as the acceptor with chymotrypsin as the linking bridge [13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
