Nanoscale Clustering of RGD Peptides at Surfaces Using Comb Polymers. 2. Surface Segregation of Comb Polymers in Polylactide
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- 作者：Darrell J. Irvine ; Anne-Valerie G. Ruzette ; Anne M. Mayes ; and Linda G. Griffith
- 刊名：Biomacromolecules
- 出版年：2001
- 出版时间：June 2001
- 年：2001
- 卷：2
- 期：2
- 页码：545 - 556
- 全文大小：278K
- 年卷期：v.2,no.2(June 2001)
- ISSN：1526-4602
文摘
Part 1 of these studies described poly(methyl methacrylate-r-polyoxyethylene methacrylate) P(MMA-r-POEM) comb polymers that present Arg-Gly-Asp (RGD) peptides at a surface in nanoscale clusters on aprotein-resistant background for control of cell adhesion. Here in part 2, we examine surface segregation ofthese peptide-modified and unmodified comb polymers blended with polylactide (PLA) as a self-assemblyapproach suitable for surface modification of porous tissue engineering scaffolds. Multiple thermodynamicdriving forces for surface enrichment of the comb polymer are exploited by annealing PLA/P(MMA-r-POEM) blends above the glass transition of the blend components but below the melting point of PLA,while in contact with water. Predictions of the interfacial composition profiles of annealed blends weremade using a self-consistent field (SCF) lattice model. The calculations predict strong enrichment of thecomb in the top ~50 Å of blends, and organization of comb molecules in quasi-2D conformations atthe interface, similar to the apparent structure of pure comb surfaces in contact with water described inpart 1. Experimentally, PLA/comb blend surfaces were characterized by contact angle measurements,XPS, quantification of ligand-cluster surface density and stability by AFM and fluorescent nanospherelabeling, and cell attachment assays. These data were consistent with SCF predictions, showing significantenrichment of the comb at water-annealed surfaces and RGD cluster densities consistent with 2Dconformations for comb molecules in the surface layer. Bulk miscibility of the blends was verified by dynamicrheometry, small-angle neutron scattering, DSC and X-ray diffraction studies. Surface segregation ofcombs provided tunable cell adhesion on PLA through surface-localized nanoclusters of RGD atop a cell-resistant background.