AVS 50th International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI-WeP

Paper BI-WeP4
Deposition of Lipid DPPC Monolayer on SiO@sub 2@ Surface using OTS Self-assembled Monolayer Islands as Anchor Molecules

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: M. Takizawa, The Graduate University for Advanced Studies, Japan
Authors: M. Takizawa, The Graduate University for Advanced Studies, Japan
Y.H. Kim, The Graduate University for Advanced Studies, Japan
T. Urisu, The Graduate University for Advanced Studies and Institute for Molecular Science, Japan
Correspondent: Click to Email
Bilayer lipid membranes (BLMs) supported on the gold surface are active research target from the viewpoint of application to the biosensors. It is reported that the stability of the membrane can be extended significantly by using the "anchor molecules", i.e. the synthesized thiolipid which is chemically anchored to the gold surface. In this work, we have examined for the first time the deposition of DPPC (dipalmitoyl phoshatidylcholine) monolayer on SiO@sub 2@ surface using OTS (n-octadecyltrichlorosilane) self-assembled monolayer (SAM) islands as anchor molecules. OTS SAMs have been deposited by dipping the Si (111) substrates with thermally oxidized SiO@sub 2@ surface layer into ~10 % toluene solution (containing small amount of water) at a room temperature. After deposition of OTS SAM island, the DPPC monolayer was transferred to the substrates by Langmuir-Brodgett method at the surface pressure of 35 mN/m. The height of the OTS SAM island measured by AFM was ~2 nm, which is consistent with a previous report. The surface morphology measurements by AFM after the DPPC transfer shows that the flat DPPC monolayer is deposited almost completely filling the (hydrophilic) SiO@sub 2@ surface area-selectively. On the (hydrophobic) OTS SAM island surface, on the other hand, DPPC monolayer deposition was not observed. Instead, small lumps of condensed DPPC molecules were observed on the surfaces and the edges of the OTS islands. The surface of the DPPC monolayer on the SiO@sub 2@ area was almost the same height as the OTS island surface. These results indicate that the OTS SAM island has a potential of effective anchor molecules in DPPC BLM depositions on SiO@sub 2@ surfaces.