A Stiff Injectable Biodegradable Elastomer

Abstract

Injectable materials often have shortcomings in mechanical and drug-eluting properties that are attributable to their high water contents. A water-free, liquid four-armed PEG modified with dopamine end groups is described which changed from liquid to elastic solid by reaction with a small volume of Fe3+ solution. The elastic modulus and degradation times increased with increasing Fe3+ concentrations. Both the free base and the water-soluble form of lidocaine could be dissolved in the PEG4-dopamine and released in a sustained manner from the cross-linked matrix. PEG4-dopamine was retained in the subcutaneous space in vivo for up to 3 weeks with minimal inflammation. This material’s tailorable mechanical properties, biocompatibility, ability to incorporate hydrophilic and hydrophobic drugs and release them slowly are desirable traits for drug delivery and other biomedical applications.

Light‐triggered stabilization of microgel aggregates

“…Most of the PEG end groups (70%) were functionalized with CAA as confirmed by 1 H‐NMR (Figure S2). These conversion rates are comparable with those reported for similar multiarmed PEG polymers . Molecular weights of PEG 4 and PEG 4 ‐CAA were 1426 and 1949 Da, respectively, as determined by gel permeation chromatography (Figure S3), confirming the 1 H‐NMR results.…”

“…These conversion rates are comparable with those reported for similar multiarmed PEG polymers. 27,28 Molecular weights of PEG 4 and PEG 4 -CAA were 1426 and 1949 Da, respectively, as determined by gel permeation chromatography ( Figure S3), confirming the 1 H-NMR results. Moreover, the UVvis spectrum of the PEG 4 -CAA conjugate showed two absorption maxima at 234 and 313 nm, which are indicative of the presence of CAA 29 (Figure S4).…”

Light-triggered antifouling coatings for porous silicon optical transducers

“…This yield is comparable with the efficiencies reported by us and by others for modification of PEG 4 with similar molecular weight. For example, our previous reports of substituting PEG 4 with dopamine showed substitution rates of about 77% …”

Long-Lasting Antifouling Coating from Multi-Armed Polymer

“…Both spectra revealed a narrow, dominant peak at 280 nm, characteristic of non-oxidized dopamine groups. 23 A slight broadening of the peak, in the range of 310-370 nm was observed in the recovered PEG 4 –dopamine, confirming the oxidation process revealed by 1 H NMR spectroscopy.…”