Biomimetic Dextran Coatings On Silicon Wafers: Thin Film Properties And Wetting
- PDF / 235,419 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 75 Downloads / 167 Views
B10.7.1
Biomimetic Dextran Coatings On Silicon Wafers: Thin Film Properties And Wetting Michela Ombelli, David M. Eckmann1 and Russell J. Composto2 Department of Chemistry, University of Perugia, Perugia, I-06123, Italy 1 Department of Anesthesia and The Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, 19104-4283, U.S.A. 2 Department of Materials Science and Engineering and Center for Bioactive Materials and Tissue Engineering, University of Pennsylvania, Philadelphia, PA 19104-6272, U.S.A. ABSTRACT There has been much recent interest in polysaccharide coatings for biotechnology applications. We obtained highly wettable dextran coatings applied to flat silicon wafer surfaces through a two-step process: in the first step, the silicon is aminated by the deposition of a selfassembled monolayer of 3-aminopropyltriethoxysilane (APTES); in the second step, polydisperse and low dispersity dextrans with molecular weights ranging from 1 kDa to 100 kDa are covalently grafted along the backbone to the surface amino groups to achieve strong interfacial anchoring. The effect of dextran concentration on film thickness and contact angle is investigated. Atomic force microscopy (AFM) has been employed to characterize surface roughness and coverage of the dextrans as well as the APTES monolayers. The synthetic surfaces were also tested for gas bubble adhesion properties.
INTRODUCTION The failure to achieve control over the chemical and biological processes at the interface between host tissues and an alien material may lead to unfavorable host responses such as thrombous formation and chronic inflammation. The biocompatibility of an implanted material in contact with biological fluids, such as blood or tears, essentially depends on the interaction between its surface and the host tissue. Extensive research is being carried out to gain a better understanding of these interfacial processes. A trend has emerged that aims to develop material surfaces whose properties resemble or mimic the biologically compatible external glycocalyx of the cellular membrane. The glycocalyx [1] is composed of a dense array of highly hydrated polysaccharides and proteoglycans that collectively provide a steric repulsive barrier to minimize undesirable protein and platelet interactions and adsorption. Hydrophilic polysaccharides [2-4] in general and dextrans [5] in particular, covalently linked to the surfaces of biomedical devices offer increased wettability and a marked decrease of cell and bacterial adhesion. Dextrans are hydrophilic and non-charged natural polymeric carbohydrates, and are especially interesting for these purposes because of their excellent biocompatibility and the wide range of molecular weights that are readily available. The goal of the present study has been to create glycocalyx-like surfaces which inhibit the adhesion of blood components, possessing a range of both polydisperse and low-dispersity dextrans, grafting densities and thickness. Biomimetic surfaces prepared by this strategy show
B1
Data Loading...
