The application of amine-terminated silicon quantum dots on the imaging of human serum proteins after polyacrylamide gel electrophoresis (PAGE).

Novel amine-terminated silicon (Si) quantum dots (QDs) were synthesized and applied for the detection of human serum proteins on gels directly after polyacrylamide gel electrophoresis (PAGE). The diameter of these stable amine-terminated Si QDs was in the range of 0.5-2.0 nm. In this study, the fluorescent imaging conditions, such as the buffer solution, pH value, buffer concentration and quantity of Si QDs, were optimized and the possible mechanisms of Si QDs-protein interaction were analyzed. The mode of Si QDs and human serum albumin association was found to occur by hydrogen bond interactions; this was probably attributed to the interaction between the amino group of amine-terminated Si QDs and the carboxyl group of proteins. Meanwhile, human serum proteins separated by native 1D and native 2D electrophoresis were detected by Si QD-based fluorescent imaging. Some proteins, such as isoform 1 of α-1-antitrypsin, complement C3 (Fragment) and hemopexin, which were identified by mass spectrometry (MS), were easily detected by using Si QDs, but not with CBB-R250 staining. The Si QDs-based fluorescent imaging technique with high resolution is a sensitive and dependable method for direct detection of human serum proteins, and has enormous potential in clinical diagnosis.