Studies of the surface layer structure and properties of poly (styrene/alpha-t-butoxy-omega-polyglycidol) microspheres by carbon nuclear magnetic resonance, X-ray photoelectron spectroscopy, and the adsorption of human serum albumin and gamma-globuli

摘要

The composition and properties of the surface layers of poly(styrene/alpha-t-butoxy-omega-polyglycidol) [poly(styrene/VB-polyGL)] microspheres synthesized by the radical copolymerization of styrene and alpha-t-butoxy-omega-vinylbenzyl-polyglycidol (VB-polyGL) macromonomers [number-average molecular weight (M-n) = 950 or 2700] were investigated with X-ray photoelectron spectroscopy, C-13 NMR, and the adsorption of human serum albumin and gamma-globulins. The number-average diameter of the synthesized microspheres was 220 nm. Their surface layers were rich in polyglycidol, with polyglycidol-to-polystyrene unit ratios of 0.443 (VB-polyGL with M. = 950) and 0.427 (VB-polyGL with Mn = 2700). In suspensions of poly(styrene/VB-polyGL) particles in D2O, the polymer chains in the polyglycidol-rich surface layers were highly mobile, allowing the registration of polyglycidol C-13 NMR spectra with standard procedures for polymer solutions. In these spectra, the signals of the relatively immobile polystyrene segments were absent. The spin-lattice relaxation times (T-1) measured for polyglycidol in the microsphere surface layers and for VB-polyGL macromonomers in solution were very close, indicating similar degrees of motion in bound (in particle surface layers) and free (in solution) polyglycidol macromolecules. Studies of protein adsorption revealed that hydrophilic polyglycidol layers were protein-repellent. It was found that longer polyglycidol chains in particle surface layers were more mobile (higher T-1 values) and provided better protection against protein adsorption. (C) 2003 Wiley Periodicals, Inc. [References: 24]