Synthesis and biocompatibility of a novel silicone hydrogel containing phosphorylcholine

Molecular Dynamics Simulation of Hydrogels Based on Phosphorylcholine-Containing Copolymers for Soft Contact Lens Applications

The structure and dynamics of copolymers of 2-hydroxyethyl methacrylate (HEMA) with 2-methacryloyloxyethyl phosphorylcholine (MPC) were studied by molecular dynamics simulations. In total, 20 systems were analyzed. They differed in numerical fractions of the MPC in the copolymer chain, equal to 0.26 and 0.74, in the sequence of mers, block and random, and the water content, from 0 to 60% by mass. HEMA side chains proved relatively rigid and stable in all considered configurations. MPC side chains, in contrast, were mobile and flexible. Water substantially influenced their dynamics. The copolymer swelling caused by water resulted in diffusion channels, pronounced in highly hydrated systems. Water in the hydrates existed in two states: those that bond to the polymer chain and the free one; the latter was similar to bulk water but with a lower self-diffusion coefficient. The results proved that molecular dynamics simulations could facilitate the preliminary selection of the polymer materials for specific purposes before their synthesis.

Development of Poly(2-Methacryloyloxyethyl Phosphorylcholine)-Functionalized Hydrogels for Reducing Protein and Bacterial Adsorption

A series of hydrogels with intrinsic antifouling properties was prepared via surface-functionalization of poly(2-hydroxyethyl methacrylate) [p(HEMA)]-based hydrogels with the biomembrane-mimicking zwitterionic polymer, poly(2-methacryloyloxyethyl phosphorylcholine) [p(MPC)]. The p(MPC)-modified hydrogels have enhanced surface wettability, high water content retention (61.0%-68.3%), and good transmittance (>90%). Notably, the presence of zwitterionic MPC moieties at the hydrogel surfaces lowered the adsorption of proteins such as lysozyme and bovine serum albumin (BSA) by 73%-74% and 59%-66%, respectively, and reduced bacterial adsorption by approximately 10%-73% relative to the unmodified control. The anti-biofouling properties of the p(MPC)-functionalized hydrogels are largely attributed to the dense hydration layer formed at the hydrogel surfaces by the zwitterionic moieties. Overall, the results demonstrate that biocompatible and antifouling hydrogels based on p(HEMA)-p(MPC) structures have promising potential for application in biomedical materials.

Preparation, material properties and antimicrobial efficacy of silicone hydrogel by modulating silicone and hydrophilic monomer

The present work proposes to investigate two series of silicone hydrogel materials for their characterization, water content, surface wettability, transmittance, mechanical property, oxygen permeability (Dk), and bacterial attachment as potential contact lens materials and discuss the relationships between water affinity and optical, mechanical, oxygen permeable and biological properties. One of the series of silicone hydrogels is presented on the basis of 3-(methacryloyloxy)propyltris(trimethylsiloxy)silane (TRIS), 3-(3-methacryloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (BIS) and 2-hydroxyethyl methacrylate (HEMA) with different silicone monomers/HEMA ratios. The other is presented on the basis of TRIS, BIS, HEMA and N,N-dimethylacrylamide (DMA) with different DMA/HEMA ratios. The results showed that the water affinity could be modulated by the hydrophilic methacrylate. The equilibrium water content (EWC) increased and the water static contact angle (WCA) value decreased with the increase of hydrophilic monomers. Overall, the results demonstrated that visible light transmittance tends to increase and tensile mechanical properties presented in declining trend depending on the increasing EWC. The Dk value decreased first and then increased when the EWC was from 20 to 60%. The reversion point of EWC was about 42.5% The amount of Staphylococcus aureus attached on the surface of the silicone hydrogels was dropped from 10⁴ to 10³ while the WCA was at 55^°. This work may provide information on preparing functional silicone hydrogels for contact lenses application.

Preparation of a photo- and thermo-responsive topological gel from anthracene-modified polyrotaxanes

A topological gel was formed from anthracene-modified polyrotaxanes (An-PRs) under UV irradiation, and the gel can turn back to a sol under thermal treatment due to the dimerization between the anthracene units and the dissociation of the formed dimer.

Promoting cell adhesion on slippery phosphorylcholine hydrogel surfaces

The growing interest in regenerative medicine has created a need for superior polymer matrices that suit multiple physical, mechanical, and biological requirements. While the phospholipid bilayer of a cell membrane is considered optimal for interacting with biologics, polymeric materials composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) offer a cell membrane-like synthetic alternative. In this work, thiol-containing phosphorylcholine polymers were synthesized by radical copolymerization of a lipoic acid-functionalized methacrylate with MPC. The canonical cell adhesion oligopeptide (GRGDS) was incorporated into the polymers by copolymerization of a GRGDS-containing methacrylamide prepared by solid phase peptide synthesis. The relative amounts of phosphorylcholine, lipoic acid and oligopeptide were controlled by the monomer feed ratios, and the polymers were characterized by NMR spectroscopy and aqueous gel permeation chromatography (GPC). These multifunctional polymers formed hydrogels rapidly (<10 minutes) by Michael addition when poly(ethylene glycol)diacrylate (PEGDA) was added at pH 9 - an initiator-free gelation performed in a completely aqueous environment. Two cell lines, live mouse skeletal muscle myoblasts (C₂C₁₂) and human ovarian cancer (SKOV3) cells, were observed to specifically attach, spread and proliferate only on hydrogels containing the GRGDS peptide sequence, with a notable dependence on peptide concentration. The remarkable hydrophilicity and biocompatibility attributed to polyMPC combined with the facile gelation conditions of these polymers affords a platform of new bio-cooperative materials suitable for cell studies.