Dopant‐Free Hydrogels with Intrinsic Photoluminescence and Biodegradable Properties

• Published in: Advanced functional materials Vol. 28; no. 34
• Main Authors: Tsou, Yung‐Hao, Zhang, Xue‐Qing, Bai, Xin, Zhu, He, Li, Zhongyu, Liu, Yanlan, Shi, Jinjun, Xu, Xiaoyang
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 22.08.2018
• Subjects: Biocompatibility; Biodegradability; biodegradable hydrogels; Biomedical materials; Carcinogens; Chelates; Chemical synthesis; Citric acid; Crosslinking; Degradation; Dextrans; Dopants; Fluorescence; Fluorescent dyes; Fluoroscopic imaging; Hydrogels; In vivo methods and tests; injectable hydrogels; Lipase; Materials science; Mechanical properties; Molecular weight; Photoluminescence; photoluminescent hydrogels; Prepolymers; Proteins; Quantum dots; Surgical implants; Sustained release; Toxicity
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201802607

Photoluminescent hydrogels that function as both injectable scaffolds and fluorescent imaging probes hold great potential for therapeutics delivery and tissue engineering. Current fluorescent hydrogels are fabricated by either conjugating or doping a fluorescent dye, fluorescent protein, lanthanide chelate, or quantum dot into polymeric hydrogel matrix. Their biomedical applications are severely limited due to drawbacks such as photostability, carcinogenesis, and toxicity associated with the above‐mentioned dopants. Here, a successful development of dopant‐free photoluminescent hydrogels in situ formed by crosslinking of biocompatible polymer precursors is reported, which can be synthesized by incorporating an amino acid to a citric acid based polyester oligomer followed by functionalization of multivalent crosslinking group through a convenient transesterification reaction using Candida Antarctica Lipase B as a catalyst. It is demonstrated that the newly developed hydrogels possess tunable degradation, intrinsic photoluminescence, mechanical properties, and exhibit sustained release of various molecular weight dextrans. In vivo study shows that the hydrogels formed in situ following subcutaneous injection exhibit excellent biocompatibility and emit strong fluorescence under visible light excitation without the need of using any traditional organic dyes. Their in vivo degradation profiles are then depicted by noninvasively monitoring fluorescence intensity of the injected hydrogel implants. Fluorescent biomaterials hold great promise for biomedical applications as they can be easily tracked by using noninvasive techniques without damaging the objective. In this study, a class of biocompatible and injectable hydrogels with intrinsic photoluminescence have been developed. Their gelation kinetics, payload release, degradation, fluorescence and mechanical properties can be modulated by adjusting chemical composition and gelation conditions.