In situ forming hydrogels with simple sol-gel transition are more practicable as injectable hydrogels for drug delivery and tissue regeneration. State-of-the-art in situ gelling systems can easily and efficiently be formed by different mechanisms in situ. Chitosan is a kind of natural polysaccharide that is widely exploited for biomedical applications due to its good biocompatibility, low immunogenicity and specific biological activities. Chitosan-based in situ gelling systems have already gained much attention as smart biomaterials in the development of several biomedical applications, such as for drug delivery systems and regeneration medicine. Herein, we review the typical in situ gelling systems based on chitosan and mechanisms involved in hydrogel forming, and report advances of chitosan-based in situ gels for the applications in drug delivery and tissue regeneration. Finally, development prospects of in situ forming hydrogels based on chitosan are also discussed in brief.
In situ gel; sol-gel transition; chitosan; drug delivery; tissue regeneration
Citation: Oi Gao, Li Liu, Xuemin Lu, Huifang Zhou In Situ Forming Hydrogels Based On Chitosan For Drug Delivery And Tissue Regeneration doi:10.1016/j.ajps.2016.07.001
Received: 26 May 2016, Accepted: 5 July 2016, Available online: 14 July 2016
Copyright: © 2016 Elsevier B.V. or its licensors or contributors. Open Access funded by Shenyang Pharmaceutical University
Conclusion and Prospects
In-situ gelling system is a minimally invasive and interesting solution in the development of drug delivery and tissue engineering approaches. Various in-situ forming hydrogels based on chitosan have been designed as injectable hydrogels-based devices for in situ drug or cell release, which rheological or mechanical and functional features could be tailored and enhanced by the composites and methods modification.
In fact, the drug delivery and scaffold could be consistent in the field of tissue engineering. The key point in tissue engineering is to construct a suitable microenvironment which includes mechanical strength, growing factors, and others for seed cells to grow, ensuring their long-term survival and further differentiation in vivo. Three dimensional porous scaffolds with growing factors are commonly used in the field of tissue engineering. In-situ forming chitosan hydrogels can be used not only as exogenous implant carrier of seed cells, but as the carrier for controlling the release of growing factors as well. However, if we carry the growing factors directly inside the chitosan hydrogels, several drawbacks emerge, like too fast releasing rate. It is always a difficult and hot spot in tissue engineering that the additive cell growing factors play the role in a timely and appropriate way effectively, in order to promote cell proliferation and directional differentiation and benefit the reconstruction of damaged tissues. Organic combination of novel growing factors controlling release systems based on chitosan microspheres, chitosan nanoparticles, chitosan nanoparticle gene complexes and chitosan-based in situ gelling systems turns out to be a possible solution to solve the above-mentioned problems. Therefore, the combination of drug delivery system and tissue engineering scaffold based on in situ chitosan hydrogels is expected to enjoy a definite promising prosperity in the medical field.
Thanks for the financial support from Shanghai Jiao Tong University on SMC-Chenxing Award for Young Scholars and Medicine-Engineering Joint Foundation (No. YG2014MS03).