Design properties of hydrogel tissue-engineering scaffolds.
ABSTRACT This article summarizes the recent progress in the design and synthesis of hydrogels as tissue-engineering scaffolds. Hydrogels are attractive scaffolding materials owing to their highly swollen network structure, ability to encapsulate cells and bioactive molecules, and efficient mass transfer. Various polymers, including natural, synthetic and natural/synthetic hybrid polymers, have been used to make hydrogels via chemical or physical crosslinking. Recently, bioactive synthetic hydrogels have emerged as promising scaffolds because they can provide molecularly tailored biofunctions and adjustable mechanical properties, as well as an extracellular matrix-like microenvironment for cell growth and tissue formation. This article addresses various strategies that have been explored to design synthetic hydrogels with extracellular matrix-mimetic bioactive properties, such as cell adhesion, proteolytic degradation and growth factor-binding.
Article: Formation of a novel heparin-based hydrogel in the presence of heparin-binding biomolecules.[show abstract] [hide abstract]
ABSTRACT: An injectable, heparin-based hydrogel system with the potential to be gelled with cells was developed. First, heparin was modified to have thiol groups by the modification of carboxylic groups of heparin with cysteamine using carbodiimide chemistry. Thiol functionalization of heparin carboxylic groups was controlled from 10% to 60% of the available COOH groups, and the retained bioactivity of the modified heparin, characterized by its binding affinity to antithrombin III, decreased with increasing functionalization. Then, the thiol-functionalized heparin was reacted with poly(ethylene glycol) diacrylate to form a hydrogel. The gelation kinetics and mechanical properties of the final gel state could be tuned by controlling cross-link density. Fibroblast cell encapsulation using this hydrogel revealed the nontoxicity of the present system. Cell proliferation inside the hydrogel was observed, and it was significantly enhanced (more than 5-fold) by the addition of fibrinogen into the hydrogel during gelation.Biomacromolecules 07/2007; 8(6):1979-86. · 5.48 Impact Factor
Article: Review: photopolymerizable and degradable biomaterials for tissue engineering applications.[show abstract] [hide abstract]
ABSTRACT: Photopolymerizable and degradable biomaterials are finding widespread application in the field of tissue engineering for the engineering of tissues such as bone, cartilage, and liver. The spatial and temporal control afforded by photoinitiated polymerizations has allowed for the development of injectable materials that can deliver cells and growth factors, as well as for the fabrication of scaffolding with complex structures. The materials developed for these applications range from entirely synthetic polymers (e.g., poly(ethylene glycol)) to purely natural polymers (e.g., hyaluronic acid) that are modified with photoreactive groups, with degradation based on the hydrolytic or enzymatic degradation of bonds in the polymer backbone or crosslinks. The degradation behavior also ranges from purely bulk to entirely surface degrading, based on the nature of the backbone chemistry and type of degradable units. The mechanical properties of these polymers are primarily based on factors such as the network crosslinking density and polymer concentration. As we better understand biological features necessary to control cellular behavior, smarter materials are being developed that can incorporate and mimic many of these factors.Tissue Engineering 11/2007; 13(10):2369-85. · 4.02 Impact Factor
Journal of the American Chemical Society 04/2007; 129(11):3040-1. · 9.91 Impact Factor