A one-step synthesis of a curcumin-derived hydrogel (curcumin content of 25-75 mol %) is reported. Curcumin is incorporated into the hydrogel backbone and cross-linked through biodegradable carbonate linkages. Curcumin as a part of the polymer backbone is protected from oxidation and degradation, while hydrogel hydrolysis results in the release of active curcumin. Nontoxic poly(ethylene glycol) and desaminotyrosyl-tyrosine ethyl ester are used to tune the hydrophilic/hydrophobic hydrogel properties. In this way, hydrogels with a wide range of physical properties including water-uptake (100-550%) and compression moduli (7-100 kPa) were obtained. Curcumin release is swelling-controlled and could be extended to 80 days. In vitro, curcumin-derived hydrogels showed selective cytotoxicity against MDA-MB-231 (IC(50) 9 μM) breast cancer cells but no cytotoxicity to noncancerous quiescent human dermal fibroblasts even at high curcumin concentrations (160 μM). One possible application of these curcumin-derived hydrogels is as soft tissue filler after surgical removal of cancerous tissue.

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Introduction: Biodegradable stents present challenges during percutaneous coronary intervention (PCI) because they are typically radiolucent. For the same reason they cannot be visualized in vivo with clinical CT. By impregnating a contrast agent in the stents’ polymer coating, the stents can be seen during PCI and their degradation can be tracked in vivo using serial CT imaging. We evaluated the degradation of a polymer coated magnesium (Mg) stent in a bioreactor using dual energy microCT. Methods: Bare Mg stents with 125 μm strut thickness were coated with either a mixture of poly(lactic-co-glycolic acid) (PLGA) and triiodobenzoic acid (TIBA) or PLGA and iodinated dendrimer (ID), deployed in latex tubing, and imaged using high resolution microCT (eXplore CT120, GE) at both 80kVp and 120kVp. Stents were exposed to physiological flow in a bioreactor for 5 days, removed and dual energy microCT was repeated using same protocol. Dual energy images were processed using a custom Matlab algorithm, and the iodinated polymer was digitally segmented from the Mg struts. Results: Images of stents at baseline coated with both PLGA-ID and PLGA-TIBA showed a marked increase in CT attenuation. Images of degraded stents coated with PLGA-TIBA showed a loss of attenuation in the polymer coating but little degradation, which suggests the small TIBA molecules was not retained in the polymer. Using dual energy CT enabled segmentation of the struts and polymers. Conclusions: We have demonstrated that the radio-opacity of polymer-coated biodegradable stents can be improved with the addition of an X-ray contrast agent during the process of polymer coating with microCT. The results suggest that the degradation of biodegradable stents could be tracked in vivo. This approach could help with stent deployment and determine when the standard dual anti-platelet therapy can be stopped based on degradation as assessed with dual energy CT.