Injectable and biodegradable hydrogels: gelation, biodegradation and biomedical applications

• Published in: Chemical Society reviews 2012-03, Vol.41 (6), p.2193-2221
• Main Authors: Li, Yulin, Rodrigues, Joo, Toms, Helena
• Format: Article
• Language: English
• Subjects: Biomedical Technology; Drug Delivery Systems; Gels - chemistry; Gels - metabolism; Hydrogels - chemistry; Hydrogels - metabolism
• ISSN: 0306-0012; 1460-4744
• DOI: 10.1039/c1cs15203c

Injectable hydrogels with biodegradability have in situ formability which in vitro/in vivo allows an effective and homogeneous encapsulation of drugs/cells, and convenient in vivo surgical operation in a minimally invasive way, causing smaller scar size and less pain for patients. Therefore, they have found a variety of biomedical applications, such as drug delivery, cell encapsulation, and tissue engineering. This critical review systematically summarizes the recent progresses on biodegradable and injectable hydrogels fabricated from natural polymers (chitosan, hyaluronic acid, alginates, gelatin, heparin, chondroitin sulfate, etc. ) and biodegradable synthetic polymers (polypeptides, polyesters, polyphosphazenes, etc. ). The review includes the novel naturally based hydrogels with high potential for biomedical applications developed in the past five years which integrate the excellent biocompatibility of natural polymers/synthetic polypeptides with structural controllability via chemical modification. The gelation and biodegradation which are two key factors to affect the cell fate or drug delivery are highlighted. A brief outlook on the future of injectable and biodegradable hydrogels is also presented (326 references). We review recent natural/synthetic biodegradable and injectable hydrogels, highlighting the effect of gelation and biodegradation on their biomedical applications.