Ring Opening Metathesis Polymerization of Bicyclic α,ß-Unsaturated Anhydrides for Ready-to-be-grafted Polymers Having Tailored pH-Responsive Degradability.

Polymers having α,ß-unsaturated anhydrides as repeating units were synthesized by ring opening metathesis polymerization (ROMP). The anhydride moieties were ready-to-be-grafted with amines to form acid-labile cis-α,ß-unsaturated acid amide linkages. The pH-responsive reversible de-grafting can be controlled by changing the intramolecular accessibility between acid and amide groups. The alendronate-grafted ROMP polymers showed distinct pH-dependent cytotoxicity according to the anhydride structures.

Alleviation of capsular formations on silicone implants in rats using biomembrane-mimicking coatings.

Despite their popular use in breast augmentation and reconstruction surgeries, the limited biocompatibility of silicone implants can induce severe side effects, including capsular contracture - an excessive foreign body reaction that forms a tight and hard fibrous capsule around the implant. This study examines the effects of using biomembrane-mimicking surface coatings to prevent capsular formations on silicone implants. The covalently attached biomembrane-mimicking polymer, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), prevented nonspecific protein adsorption and fibroblast adhesion on the silicone surface. More importantly, in vivo capsule formations around PMPC-grafted silicone implants in rats were significantly thinner and exhibited lower collagen densities and more regular collagen alignments than bare silicone implants. The observed decrease in α-smooth muscle actin also supported the alleviation of capsular formations by the biomembrane-mimicking coating. Decreases in inflammation-related cells, myeloperoxidase and transforming growth factor-ß resulted in reduced inflammation in the capsular tissue. The biomembrane-mimicking coatings used on these silicone implants demonstrate great potential for preventing capsular contracture and developing biocompatible materials for various biomedical applications.

Preparation of non-aggregated fluorescent nanodiamonds (FNDs) by non-covalent coating with a block copolymer and proteins for enhancement of intracellular uptake.

Fluorescent nanodiamonds (FNDs) are very promising fluorophores for use in biosystems due to their high biocompatibility and photostability. To overcome their tendency to aggregate in physiological solutions, which severely limits the biological applications of FNDs, we developed a new non-covalent coating method using a block copolymer, PEG-b-P(DMAEMA-co-BMA), or proteins such as BSA and HSA. By simple mixing of the block copolymer with FNDs, the cationic DMAEMA and hydrophobic BMA moieties can strongly interact with the anionic and hydrophobic moieties on the FND surface, while the PEG block can form a shell to prevent the direct contact between FNDs. The polymer-coated FNDs, along with BSA- and HSA-coated FNDs, showed non-aggregation characteristics and maintained their size at the physiological salt concentration. The well-dispersed, polymer- or protein-coated FNDs in physiological solutions showed enhanced intracellular uptake, which was confirmed by CLSM. In addition, the biocompatibility of the coated FNDs was expressly supported by a cytotoxicity assay. Our simple non-covalent coating with the block copolymer, which can be easily modified by various chemical methods, projects a very promising outlook for future biomedical applications, especially in comparison with covalent coating or protein-based coating.