Abstract:The focus in the field of biomedical engineering has shifted in recent years to biodegradable polymers and, in particular, polyesters. Dozens of polyester-based medical devices are commercially available, and every year more are introduced to the market. The mechanical performance and wide range of biodegradation properties of this class of polymers allow for high degrees of selectivity for targeted clinical applications. Recent research endeavors to expand the application of polymers have been driven by a need to target the general hydrophobic nature of polyesters and their limited cell motif sites. This review provides a comprehensive investigation into advanced strategies to modify polyesters and their clinical potential for future biomedical applications.
Anterior cruciate ligament (ACL) is one of the most vulnerable ligaments of the knee. ACL impairment results in episodic instability, chondral and meniscal injury and early osteoarthritis. The poor self-healing capacity of ACL makes surgical treatment inevitable. Current ACL reconstructions include a substitution of torn ACL via biological grafts such as autograft, allograft. This review provides an insight of ACL structure, orientation and properties followed by comparing the performance of various constructs that have been used for ACL replacement. New approaches, undertaken to induce ACL regeneration and fabricate biomimetic scaffolds, are also discussed.
The brittle structure of polymer-bioactive-glass hybrids is a hurdle for their biomedical applications. To address this issue here, we developed a novel method to cease the overcondensation of bioactive-glass by polymer cross-linking. Here, an organosilane-functionalized gelatin methacrylate (GelMA) is covalently bonded to a bioactive-glass during the sol-gel process, and the condensation of silica networks is controlled by photo-cross-linking of GelMA. The physicochemical properties and mechanical strength of these hybrids are tunable by the incorporation of secondary cross-linking agents. These hydrogels display elastic properties with ultimate compression strain above 0.2 mm·mm(-1) and tunable compressive modulus in the range of 42-530 kPa. In addition, these hydrogels are bioactive because they promoted the alkaline phosphatase activity of bone progenitor cells. They are also well-tolerated in the mice subcutaneous model. Therefore, our method is efficient for the prevention of overcondensation and allows preparation of soft bioactive hydrogels from organic-inorganic matrices, suitable for soft and hard tissue regeneration.
Synthesis, characterization and cytotoxicity evaluation of copolymers based on polyethylene glycol monmethyl ether-g-poly(methacrylic acid-co-methyl methacrylate) are reported via a polymeric precursor method. Grafting was accomplished based on direct condensation reaction in the presence of dicyclohexylcarbodiimide as an esterification-promoting agent catalyzed by dimethylamino pyridine. Polyethylene glycol grafted copolymers were characterized using various spectroscopic techniques; in addition, their biocompatibility was studied. Manifestation of bands assigned to the ester functional groups in Fourier transform infrared spectra and nuclear magnetic resonance was employed for structural characterization of the grafted copolymers. Performance of grafting reaction was guaranteed by determination of grafting efficacy. Cytotoxicity evaluations of the grafted copolymer using L929 fibroblast cell line elucidated acceptable biocompatibility profile; consequently, the applicability of the copolymers is confirmed for biomedical applications.
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