Abstract
Thermosensitive alginate–poloxamer (ALG–POL) copolymer with an optimal POL content was synthesized, and it was used to combine with silk fibroin (SF) for building ALG–POL/SF hydrogels with dual network structure. Mesoporous bioactive glass (BG) nanoparticles (NPs) with a high level of mesoporosity and large pore size were prepared and they were employed as a vehicle for loading insulin-like growth factor-1 (IGF-1). IGF-1-loaded BG NPs were embedded into ALG–POL/SF hydrogels to achieve the controlled delivery of IGF-1. The resulting IGF-1-loaded BG/ALG–POL/SF gels were found to be injectable with their sol-gel transition near physiological temperature and pH. Rheological measurements showed that BG/ALG–POL/SF gels had their elastic modulus higher than 5kPa with large ratio of elastic modulus to viscous modulus, indicative of their mechanically strong features. The dry BG/ALG–POL/SF gels were seen to be highly porous with well-interconnected pore characteristics. The gels loaded with varied amounts of IGF-1 showed abilities to administer IGF-1 release in approximately linear manners for a few weeks while effectively preserving the bioactivity of encapsulated IGF-1. Results suggest that such constructed BG/ALG–POL/SF gels can function as a promising injectable biomaterial for bone tissue engineering applications.
Highlights
The extracellular matrix (ECM) is the noncellular component presenting within all tissues and organs, and it usually has three-dimensional porous architecture
Thermosensitive ALG–POL copolymer containing a necessitated percentage of POL was successfully synthesized. Such synthesized ALG–POL was found to be suitable for constructing hydrogels with dual network structure through combining with silk fibroin (SF)
The optimally obtained ALG–POL/SF gels were injectable at room temperature and mechanically strong with their sol-gel transition near physiological pH and temperature
Summary
The extracellular matrix (ECM) is the noncellular component presenting within all tissues and organs, and it usually has three-dimensional porous architecture. Polymer hydrogels, which behave like soft and elastic objects, are usually constructed by physically or chemically crosslinked macromolecules They contain large amounts of water while having highly porous architecture with tailorable physiochemical properties and easy diffusivity of small molecules. Despite the convenience of preparation, so constructed alginate hydrogels often undergo progressive disintegration in vivo due to the ionic exchange between Ca2+ in the gels and monovalent cations (such as Na+ and K+) coming from the host tissue surrounding the applied gels, which often results in their unstable dimension and uncontrolled properties [7,8] Another type of physically crosslinked alginate hydrogel was engineered by grafting a type of thermosensitive polymer, poloxamer (Pluronic F127), onto alginate backbone, and the sol-gel transition of alginate–poloxamer (ALG–POL) hydrogels can be trigged by thermosensitive action arisen from the poloxamer component [9]. Some formulated IGF-loaded BG/ALG–POL/SF gels were found to be injectable and mechanically strong, and to have affirmative abilities to control the release of IGF-1 while preserving its bioactivity
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