Temperature And PH-dependent Thermodynamic Studies Of Quantum Dot-protein Binding By Fluorescence Correlation Spectroscopy

The fluorescence correlation spectroscopy(FCS)has high sensitivity and stability which will not destroy the balance of system and can realize the real-time monitoring,so FCS technology has been more and more widely used in chemistry,life sciences and other fields,especially in the field of biochemistry in situ measurements which shows an unique advantage.When the quantum dots(QDs)were introduced into proteins or cells,they can be coated by many proteins and form a shell of protein called "protein crown".Thus,the quantum dots encapsulated by proteins will have better biocompatibility and more biological researches.But many parameters will affect the interaction between QDs and proteins,such as size and surface properties of quantum dots,the nature of the protein,the medium environment(temperature and p H)and so on.This article study the typical binding between carboxyl water-soluble quantum dots and the bovine serum albumin binding force with different temperatures and p H under the condition of buffer and in serum and plasma based on fluorescence lifetime correlation spectroscopy at the single molecular level and explored the their thermodynamics and binding mode.Based on fluorescence correlation spectroscopy,it also explored the inflouence of the relative range to the fluorescent life of different thickness of protein layers on quantum dots.The results showed that the fluorescent life of quantum dots moved into the direction of short wavelength.The percentage of long-lived species decreased and the percentage of short-lived species increased.The research have important significance for the studies of the application of nanometer materials in situ and biological toxicity.