Application of Carbon Quantum Dots in Fluorescent Imaging of Human Serum Proteins after Polyacrylamide Gel Electrophoresis

A new method of carbon quantum dots (CQDs) fluorescent imaging for human serum proteins detection after polyacrylamide gels electrophoresis (PAGE) is established. Polyacrylamide gel electrophoresis is one of the most general and powerful technique to separate complex biosamples, and it is widely used in molecular biology, biochemistry and medicine. With the evolution of clinical proteomics, the development of a novel method to detect serum proteins after PAGE with high resolution and high sensitivity is of great significant. As far as we know, the carbon quantum dots have not been applied in the detection of serum proteins after PAGE. The fluorescent carbon quantum dots were synthesized by a one-step microwave pyrolysis method: glycerol and phosphate buffer (7.1 mmolL -1 , pH 7.4) (φ=70%) was mixed evenly, and then put the solu- tion into the advanced microwave digestion system and heated for 14 min (750 W), the colorless solution turned to yellow after reaction. The yellow solution was diluted into the incubation solution with HOAc-NaOAc buffer (80 mmolL -1 , pH 2.7), and then used for staining serum proteins. The emission and excitation spectra of carbon quantum dots were measured, and the excitation wavelength allowed the use of an ultraviolet lamp at 365 nm for the fluorescent imaging. In order to inves- tigate the performance of CQDs fluorescent imaging, the dilution of human serum samples separated by electrophoresis was used for detection, and was compared with traditional method of CBB-R250 staining and silver staining. The results sug- gested that CQDs based on fluorescent imaging could effectively detect human serum proteins with high sensitivity and resolution. The sensitivity of CQDs imaging was higher than CBB staining and comparable to silver staining. Therefore, the CQDs fluorescent imaging could be an inexpensive, time-saving, pollution-free and convenient method with high sensitivity and resolution for the detection of human serum proteins. It demonstrates the CQDs fluorescent imaging technology has great significant prospects in the development of biotechnology and nanotechnology. Keywords carbon quantum dot; polyacrylamide gel electrophoresis; protein; fluorescent imaging