A new biosensing by Dielectric Dispersion Analysis of interaction between lipid membrane of liposome and target biomolecules up to 20 GHz range

This paper reports, firstly, that it was newly found by our specific Dielectric Dispersion Analysis (DDA) that plural type of bound water with different relaxation frequencies exist in a suspension of liposome of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Secondly, we observe that the interaction between the liposome and a specific target biomolecule depends on the type of target molecules (we used a protein of carbonic anhydrase from bovine (CAB) and/or cholesterol, respectively), leading to the change in dielectric relaxation at different relaxation frequency of bound water. It is finally concluded that the developed DDA method allows us to acquire the quantitative information with respect to bound water to liposomes, which gives novel physical insight on interaction between liposomes and target biomolecules (especially, protein).