| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014) | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuM |
| Session: | Biomaterial & Wet Interface Characterization |
| Presenter: | Valeria del Campo, Universidad Técnica Federico Santa María, Chile |
| Authors: | M.J. Retamal, Pontificia Universidad Católica de Chile, Instituto de Física, Chile M.A. Cisternas, Pontificia Universidad Católica de Chile, Instituto de Física, Chile S.E. Gutierrez-Maldonado, Fundación Ciencia & Vida, Chile T. Perez-Acle, Fundación Ciencia & Vida, Chile B. Seifert, Pontificia Universidad Católica de Chile, Instituto de Física, Chile M. Busch, Hamburg University of Technology (TUHH), Germany P. Huber, Hamburg University of Technology (TUHH), Germany U.G. Volkmann, Pontificia Universidad Católica de Chile, Instituto de Física, Chile V.d.C. del Campo, Universidad Técnica Federico Santa María, Chile |
| Correspondent: | Click to Email |
The design of interfaces between solid surfaces and biological molecules such as membranes and/or proteins using Si(100)/SiO2, a.k.a. bio-silicon interfaces, is an important and rapid developing area of both scientific and applied research. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. A soft hydrophilic polymer cushion could help to provide a “bio-mimetic” environment for the membrane and for membrane-spanning proteins. Several candidates to be used as soft-cushion polymers are currently under research, such as dextran, hyaluronic acid and other polysaccharides. Chitosan is a linear polysaccharide obtained by the deacetylation of chitin, which can be found in the shells of crustaceans, exoskeletons of insects, fungi and plants, thus being very easy to obtain from nature at low cost. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. We describe the formation and characterization of a phospholipid bilayer (DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (~25Å) and DPPC (~60Å) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy (AFM) we have been able to detect phase transitions in the membrane. The presence of the Chitosan interlayer as a water reservoir is essential for both DPPC bilayer formation and stability, favoring the appearance of phase transitions. Our experiments show that the proposed sample preparation from the gas phase is reproducible and provides a natural environment for the DPPC bilayer.
We thank for financial support under FONDECYT grant No. 1100882 and 1141105, and acknowledge a CONICYT scholarship of M.J.R. (Ph.D), M.A.C. (Master) and S.E.G.M. (Ph.D). U.G.V and T.P.A are grateful to the Anillo Científico Tecnológico ACT1107. S.E.G.M. and T.P.A. acknowledge funding from Programa Basal PFB16 (PIA CONICYT) and Centro Interdisciplinario de Neurociencias de Valparaiso (ICM-Economia P09-022-F). P.H., M.B. M.J.R., and U.G.V. were supported by a bilateral, german-chilean academic exchange project DAAD project no. 56206483 / CONICYT project no. PCCI 044.