Label-Free Detections of GST-fused Protein and the Interaction of Proteins via Silicon Nanowire Field-Effect Transistor

Nanosensors have been developed for recent several years, and have potential on sensing charged molecules because the properties of high-sensitivity and label-free. This thesis is about sensing the protein-protein interactions via silicon nanowire field-effect transistor. Proteins often participate in the machanisms for the maintaining of physiology in cells with such interactions. If the detections of the interactions which is not confirmed could be rapid and quantitative, that will be much helpful to realize the functions of the proteins and the realative treatments of diseases caused from the abnormal functions of proteins.
By the immobilization of proteins to the surface of the silicon nanowires, the conductance of nanowires will be affected by the electric field of the charged proteins.And we could observe the changes of the conductance caused by the association of proteins and comfirm the interaction between proteins. About calmodulin, the association of troponin I and calmodulin had been detected succefully in specific range of calcium concentration. Furthermore, we detected the association of N-type voltage-gated calcium channel and calmodulin in physiological condition. That proves the possibility and advantages of the silicon nanowire field-effect transistor as a biosensor. About Rab3A, we observed the dissociation of GDP and Rab3A in pure phosphate buffer solution. The reversible association-dissociation of GDP and Rab3A illustrates that dissociation rate should be taked in consideration in experiments about Rab3A activated by GTP.
With the advantages of GST pull-dwon assay, we have developed a reusable, label-free and high sensitivity biosensor chip which could detect the protein-protein interactions in physiological conditions, provides us to understand the function of the proteins.