Surface Grafting of Poly(l-glutamates). 1. Synthesis and Characterization

Abstract

The ring-opening polymerization of N-carboxyanhydrides (NCA) of γ-benzyl L-glutamate and γ-methyl L-glutamate from (γ-aminopropyl)triethoxysilane (APS) pretreated substrates such as silicon wafers and quartz slides was investigated. FT-IR transmission spectroscopy, circular dichroism measurements, and UV/vis spectroscopy confirmed the pure R-helix conformation of the grafted polypeptide layers. FT-IR spectroscopy also showed that the most important part of the polymer growth took place in the first 5 h of the polymerization. The average orientation of the rather rigid R-helical polypeptides, grown during a short period of time, was more perpendicular with respect to the substrate than the orientation of the polymers grown over a longer reaction time. For concentrations up to 2.0 M, the polymer growth from both NCA monomers showed a pronounced dependence on the monomer concentration. Moreover, it appeared that the higher the monomer concentration, the more perpendicular the average orientation of the helices with respect to the substrate. The thickness of the grafted polypeptide layers up to 400 Å was determined with ellipsometry and small-angle X-ray reflection measurements. The absence of chemical chain termination was demonstrated by additional polymer growth in a renewed polymerization.

Polypeptides and 100 Years of Chemistry of α‐Amino Acid N‐Carboxyanhydrides

“…Furthermore, grafting of g-Me-l-Glu-NCA on carbon black [212] and grafting of g-Bzl-l-Glu-NCA on amine-modified silica or quartz [213,214] were described. Finally, the deposition of thin polyglutamate films on neat gold was reported, [215] but it was not clarified if the binding was based on covalent bonds or through other electronic interactions.…”

Polypeptide und 100 Jahre Chemie der α‐Aminosäure‐N‐carboxyanhydride

“…Des Weiteren wurde über die Pfropfpolymerisation von g-Bzl-l-Glu-NCA auf Rußkohle [212] und auf NH 2 -modifizierten Siliciumoxiden (einschließlich Quarz) berichtet. [213,214] Es wurde sogar das Aufbringen von Polyglutamatfilmen auf reinem Gold beschrieben, [215] jedoch blieb ungeklärt, ob die Fixierung über kovalente Bindungen oder Nebenvalenzen erfolgte.…”

Sum-frequency spectroscopy and imaging of aligned helical polypeptides

“…This is accomplished by first modifying the surface with initiators for subsequent the polymer synthesis, and then growing a helical chain that is tethered to the surface (grafting from approach) [39], [40]. Surface polymerization to produce PBLG monomolecular films has been performed in the melt [41], in solution [40], [42]- [45], and by a vapor deposition polymerization [46]. Vapor deposition polymerization was used in this paper to grow a PBLG film.…”