Sensitivity enhancement of leakage current microsensor for detection of target protein by using protein denaturant

We have developed a highly-sensitive leakage current microsensor by using 1,2-dipalmitoyl-sn-glycero-3 phosphocholline (DPPC) liposome entrapping K₄[Fe(CN)₆] solution to detect existence of biomolecules especially proteins and their dynamic conditions. In this work, the addition of guanidinium hydrochloride (GuHCl) as protein denaturant successfully leads a prominent improvement in sensitivity by 129-fold of magnitude, although target protein, which is carbonic anhydrase from bovine (CAB), weakly interacts with liposome under the normal condition. Moreover, we can use it to evaluate the conformation state of CAB protein such as ´Native´, ´Molten-Globule´ and ´Unfold´ states and we can use this leakage current microsensor to detect other protein that do not have large interaction with the liposome.