Preparation Of Ratiometric PH Sensor Based On BSA-capped Gold Nanoclusters And Carbon Dots

Nano fluorescence probe had been widely applied in chemical detection, biosensors and bioimaging due to their excellent optical, physics properties and good biocompatibility. In this paper, a kind of ratiometric fluorescent p H sensor had been prepared based on BSAcapped Au NCs and FITC. Fluorescence resonance energy transfer between CDs and fluorescein isothiocyanate(FITC) were investigated. What’s more, another ratiometric fluorescent p H sensor were prepared based on CDs and FITC. The main contents are listed as follows:1. A red-emitting gold nanoclusters with maximum emission wavelength of 608 nm was prepared by using the bovine serum albumin(BSA) as coating reagent. A ratiometric fluorescent p H sensor was synthesized based on the BSA-capped Au NCs and FITC and the molar feed ratio of Au NCs to FITC were optimized. The p H sensor was characterized by fluorescence spectrophotometer, UV-Visible spectrophotometer and p H meter. The results showed that the sensitivity and sensitive range of p H probes are tunable and the p H sensor displayed an excellent reversebility between p H 6.0 and p H 9.0. MTT assays showed there were hardly no cytotoxicity of p H sensor. It indicated that the probe had the potential to detect intracellular p H.2. An amino-coated CDs with maximum emission wavelength of 445 nm was prepared based on citric acid. The interaction between CDs and FITC were investigated by using fluorescence spectrophotometer, UV-Visible spectrophotometer and steady-state/transient fluorescence spectrometer. The results indicated the presence of a fluorescence resonance energy transfer between the carbon dots and FITC. Further the efficiency of energy transfer system and the distance between donor and acceptor were calculated. Isothermal titration calorimetry(ITC) experiments showed hydrophobic force played a key role in energy transfer system. What’s more, a ratiometric fluorescent p H sensor were prepared based on CDs and FITC. The interaction between CDs, FITC and RBITC were preliminary discussed.