Quantum dot hybrid gel blotting: a technique for identifying quantum dot-protein/protein-protein interactions.

We describe an alternative to the molecular biology technique of polyacrylamide gel electrophoresis-based Western blotting and immunoprecipitation, which is an extensively used method for separating target proteins from complex cellular mixtures and for identification of protein expression and protein-protein interactions. This novel method, called quantum dot (QD) hybrid gel blotting, allows the purification and analysis of the action of QD bioconjugate-protein complexes in live cells. Moreover, these identified interactions can be correlated with spatial location in cells. QD hybrid gel blotting will be useful in the growing fields of molecular biology/proteomics and nanobiotechnology development in several respects: (1) as a method for identifying specific QD-protein interactions in cells, (2) as a method for correlating QD-protein interactions with their spatial location in live cells, (3) as a means to study the size and composition of QD bioconjugate probes/complexes; and, finally, (4) as an improvement over traditional bead-based immunoprecipitation methods for directly isolating and visualizing proteins from complex mixtures.