Biodegradable polyurethane scaffolds in regenerative medicine: Clinical translation review

Abstract

Early explorations of tissue engineering and regenerative medicine concepts commonly utilized simple polyesters such as polyglycolide, polylactide, and their copolymers as scaffolds. These biomaterials were deemed clinically acceptable, readily accessible, and provided processability and a generally known biological response. With experience and refinement of approaches, greater control of material properties and integrated bioactivity has received emphasis and a broadened palette of synthetic biomaterials has been employed. Biodegradable polyurethanes (PUs) have emerged as an attractive option for synthetic scaffolds in a variety of tissue applications because of their flexibility in molecular design and ability to fulfill mechanical property objectives, particularly in soft tissue applications. Biodegradable PUs are highly customizable based on their composition and processability to impart tailored mechanical and degradation behavior. Additionally, bioactive agents can be readily incorporated into these scaffolds to drive a desired biological response. Enthusiasm for biodegradable PU scaffolds has soared in recent years, leading to rapid growth in the literature documenting novel PU chemistries, scaffold designs, mechanical properties, and aspects of biocompatibility. Despite the enthusiasm in the field, there are still few examples of biodegradable PU scaffolds that have achieved regulatory approval and routine clinical use. However, there is a growing literature where biodegradable PU scaffolds are being specifically developed for a wide range of pathologies and where relevant pre‐clinical models are being employed. The purpose of this review is first to highlight examples of clinically used biodegradable PU scaffolds, and then to summarize the growing body of reports on pre‐clinical applications of biodegradable PU scaffolds.

Scaffold-based bone tissue engineering in microgravity: potential, concerns and implications

“…Naturally-derived biomaterials (e.g., collagen, gelatin, chitosan, starch) can offer several active cues to cells, even if may elicit immunogenic issues and the biodegradability rate can be difficult to control 42 . Synthetic polymers, e.g., polylactic acid (PLA), polycaprolactone (PCL), or polyurethane (PU), are more frequently considered due to the higher control on the degradation rate and mechanical properties 43 – 45 . Metals (e.g., titanium alloys) or inert ceramics (e.g., alumina and zirconia) can be suitable options characterized by high strength and biocompatibility, but with a limited interest in tissue engineering applications due to their non-degradability.…”

Microbial Enzyme Biotechnology to Reach Plastic Waste Circularity: Current Status, Problems and Perspectives

“…Moreover, attempts have been made to produce biofilms from the proteins of insects reared on organic waste to overcome the competition with the market of plant- and animal-derived food products [ 207 ]. It is important to report that lab-scale experiments are ongoing to synthesize more biodegradable thermoset materials, starting from mixing agriculturally derived oils with traditional precursors of polyester-type PURs [ 166 , 208 , 209 , 210 , 211 ]. The advantage of these biodegradable materials is that they can be assimilated as a carbon source by environmental organisms or at dedicated composting sites without releasing microparticles and without the need to develop a specific biotechnology in an industrial setup.…”

Bioceramics/Electrospun Polymeric Nanofibrous and Carbon Nanofibrous Scaffolds for Bone Tissue Engineering Applications

“…Biomaterials that are naturally derived (such as collagen, gelatin, chitosan, and starch) can provide cells with a variety of active stimuli and have positive characteristics such as biocompatibility and ECM resemblance [ 9 , 79 ], but even these could cause immunogenic problems, and controlling the biodegradability rate can be challenging [ 80 ]. Due to the greater control over the degradation rate and mechanical qualities, synthetic polymers, such as polylactic acid (PLA), polycaprolactone (PCL), and polyurethane (PU), are more frequently taken into consideration [ 7 , 81 , 82 ]. High strength and biocompatibility can be found in metals (such as titanium alloys) and inert ceramics (such as alumina and zirconia), but their usefulness in tissue engineering applications is limited due to their inability to degrade.…”