Designing Injectable Hydrogel from Dextran,Gelatin,and Poly(Ethylene Glycol)for Tissue Engineering Application
|Keywords||dextran gelatin four-arm poly(ethylene glycol) injectable hydrogel tissueengineering|
The dysfunction and damage of tissues and organs are one the major hazards for human healthy, also the primary reason for human diseases and death. The appearance of Tissue Engineering has brought a new solution for these worldwide problems. As a new interdisciplinary field, Tissue Engineering has fuses molecular and cell biology, materials science, clinical medicine, bioengineering, and other disciplines, through rebuild tissues, organs in vitro/in vivo, and finally figures out these tough problems facing human being.Hydrogels are physically or chemically cross-linked networks that are able to absorb large amounts of water. The application of hydrogels dates back to1960, when Wichterle first introduced the use of hydrophilic hydrogels for soft contact lens materials, after that hydrogels were widely researched in the biomedical field. During the last decade, due to the high water content property and physical properties similar to native extracellular matrix (ECM), hydrogels have been started to use as three-dimensional (3D) tissue engineering scaffolds for cell culture. Injectable hydrogels, which can be operated through painless and minimally invasive surgery, has obtained increasing attention from scientists.In this work, a two-step crosslinking network was introduced to fabricate injectable hydrogel from oxidized dextran (ODex)/amino gelatin (MGel)/4-arm polyethylene glycol)-acrylate (4A-PEG-Acr) for cell encapsulation. Primary network formed based on Schiff based reaction between ODex and MGel, then, a UV light-induced radical reaction of4A-PEG-Acr was used to produce the independent secondary network. Both of reactions were carried out under physiological condition in the presence of living cells with no toxicity. The primary network depending on natural polymers could degrade fast to provide space and nutrition for encapsulated cells growing, and secondary network could provide long-term mechanical stability. In vitro degradation experiment has shown that the ODex/MGel/4A-PEG-Acr hydrogels can degraded fast at the beginning and slow down after that, at the same time, the degradation rate of the hydrogels can be adjusted by changing the compositions. Mechanical test has shown that ODex/MGel/4A-PEG-Acr hydrogels possess excellent anti-fracture ability when they were compressed or stretched, the compression modulus of ODex/MGel/4A-PEG-Acr can reach32.27KPa in some cases. The in vitro cell culturing experiments illustrated that as prepared ODex/MGel/4A-PEG-Acr hydrogels possess favorable biocompatibility, and can promote pre-osteoblast (MC3T3-E1) cells Attaching and spreading both on the surface and within the hydrogels. The subcutaneous injection experiment performed on rats has demonstrated that ODex/MGel/4A-PEG-Acr hydrogels can be used for inject operation. Therefore, the double crosslinking hydrogel designed in this study could be a promising candidate for bone or cartilage tissue engineering.