Investigation of the Hydration of Nonfouling Material Poly(sulfobetaine methacrylate) by Low-Field Nuclear Magnetic Resonance

Abstract

The strong surface hydration layer of nonfouling materials plays a key role in their resistance to nonspecific protein adsorption. Poly(sulfobetaine methacrylate) (polySBMA) is an effective material that can resist nonspecific protein adsorption and cell adhesion. About eight water molecules are tightly bound with one sulfobetaine (SB) unit, and additional water molecules over 8:1 ratio mainly swell the polySBMA matrix, which is obtained through the measurement of T(2) relaxation time by low-field nuclear magnetic resonance (LF-NMR). This result was also supported by the endothermic behavior of water/polySBMA mixtures measured by differential scanning calorimetry (DSC). Furthermore, by comparing both results of polySBMA and poly(ethylene glycol) (PEG), it is found that (1) the hydrated water molecules on the SB unit are more tightly bound than on the ethylene glycol (EG) unit before saturation, and (2) the additional water molecules after forming the hydration layer in polySBMA solutions show higher freedom than those in PEG. These results might illustrate the reason for higher resistance of zwitterionic materials to nonspecific protein adsorptions compared to that of PEGs.

Functionalizable low-fouling coatings for label-free biosensing in complex biological media: advances and applications

“…Highly hydrophilic surfaces have been prepared by coating substrates with polymer coatings based on N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethylammonium sulfobetaine methacrylate (SBMA) [172][173][174][175]. There was no adsorption from solutions of the main plasma proteins on pSBMA brushes prepared by SI-ATRP [9,176,177]; however, fouling from blood plasma ranged from 75 to 2400 pg mm −2 and was dependent on the thickness of the brush [9,178].…”

Long circulating micelles of an amphiphilic random copolymer bearing cell outer membrane phosphorylcholine zwitterions

“…On the one hand, the strongly hydrophilic PC groups can easily adsorb more water molecules around them forming a hydration layer on the surface of micelles [57]. This tightly coupled hydration shell of the micelles is more conducive to maintain a ''camouflage'' or ''stealth'' surface, exhibiting strong anti-adsorption capacity to plasma proteins and other macromolecules.…”

Zwitterionic copolymer self-assembly for fouling resistant, high flux membranes with size-based small molecule selectivity

“…They have been shown to be highly resistant to biomolecular fouling due to their high degree of hydration [32][33][34][35][36][37]. Since this discovery, many researchers have improved the fouling resistance of membranes by attaching zwitterionic groups on their surface, by post-processing existing membranes [38][39][40][41][42][43][44] or by using zwitterionic surface-segregating additives [45][46][47].…”