Convenient and ultra-sensitive fluorescence detection of bovine serum albumin by using Rhodamine-6G modified gold...

This study comprises a convenient, rapid and very sensitive method for the determination of bovine serum albumin (BSA). The technique is based on fluorescence resonance energy transfer (FRET) between Rhodamine-6G (R6G) acting as donor and gold nanoparticles (AuNPs) acting as acceptors. This method takes advantage of AuNPs that have high quenching efficiency, therefore the absorption spectra range shifts from 521 to 635 nm when aggregation of the AuNPs takes place. Furthermore, when R6G was electrostatically self-adsorbed to the citrate-stabilized AuNPs surface the fluorescence intensity was quenched. After addition of BSA, the fluorescence intensity of the R6G recovered as BSA induced aggregation of the AuNPs and the adsorbed R6G was released to the solution. The recovery of intensity displays a linear relationship with BSA concentration over the range from 0.8 × 10^-11  M to 5.6 × 10^-11  M. The detection limit for BSA was found to be 4.58 × 10^-11  M. The proposed method exhibited rapid analysis with high selectivity for BSA determination in human urine, blood and serum samples.