A leakage current microsensor for detection of interaction between an electrolyte-entrapping liposome and protein

We have newly made a specific biomolecule microsensor measuring leakage current and impedance with minute liposome solution that interacts with biomolecules such as protein. The microsensor was fabricated with a Si surface-bulk-micromachining process. K₄[Fe(CN)₆] solution was entrapped inside of liposome of 1,2-dipalmitoyl-sn-glycero-3-phosphocholline (DPPC) and Carbonic Anhydrase from Bovine (CAB) was used as added protein for the interaction. A clear leakage in nA order was observed for the CAB, indicating the microsensor detects the CAB through the liposome-protein interaction. The detectivity increased by about 7 times and the volume of solution was decreased by about 10,000 from the previous result.