Surface modification

About: Surface modification is a research topic. Over the lifetime, 35544 publications have been published within this topic receiving 859567 citations.

Wet-Chemical Analysis of Surface Concentration of Accessible Groups on Different Amino-Functionalized Mesoporous SBA-15 Silicas

Abstract: Surface functionalization is one of the key steps toward the utilization of mesoporous materials in different applications. In this study, we characterized amino-functionalized mesoporous SBA-15 silicas that have been prepared by different means; co-condensation, post-grafting of amino-silanes, and surface hyperbranching polymerization of poly(ethylene imine). Special focus is put on the accessibility of the introduced function. The materials are thoroughly characterized both by structural and by surface chemical means. We generally observe a good agreement between the C-value derived from BET surface area analysis, the number of accessible amine groups determined by quantitative imine reaction in solution, and zeta-potential measurements. Furthermore, indirect information about differences in the number of amine groups present on the outside surface of the particles can also be obtained. Our results clearly show that there are large differences between the availability of the amine function for materials...

Biomimetic Polymer/Apatite Composite Scaffolds for Mineralized Tissue Engineering

Abstract: The material surface must be considered in the design of scaffolds for bone tissue engineering so that it supports bone cells adhesion, proliferation and differentiation. A biomimetic approach has been developed as a 3D surface modification technique to grow partially carbonated hydroxyapatite (the bonelike mineral) in prefabricated, porous, polymer scaffolds using a simulated body fluid in our lab. For the rational design of scaffolding materials and optimization of the biomimetic process, this work focused on various materials and processing parameters in relation to apatite formation on 3D polymer scaffolds. The apatite nucleation and growth in the internal pores of poly(L-lactide) and poly(D,L-lactide) scaffolds were significantly faster than in those of poly(lactide-co-glycolide) scaffolds in simulated body fluids. The apatite distribution was significantly more uniform in the poly(L-lactide) scaffolds than in the poly(lactide-co-glycolide) scaffolds. After incubation in a simulated body fluid for 30 d, the mass of poly(L-lactide) scaffolds increased approximately 40%, whereas the mass of the poly(lactide-co-glycolide) scaffolds increased by about 15% (see Figure). A higher ionic concentration and higher pH value of the simulated body fluid enhanced apatite formation. The effects of surface functional groups on apatite nucleation and growth were found to be more complex in 3D scaffolds than on 2D films. Surprisingly enough, it was found that carboxyl groups significantly reduced the apatite formation, especially on the internal pore surfaces of 3D scaffolds. These findings are critically important in the rational selection of materials and surface design of 3D scaffolds for mineralized tissue engineering and may contribute to the understanding of biomineralization as well.SEM micrograph of a poly(L-lactide) scaffold.