Degradable Self‐healable Networks for Use in Biomedical Applications

Abstract

Among biomaterials, 3D networks with capacities to absorb and retain large quantities of water (hydrogels) or withstand significant deformation and stress while recovering their initial structures at rest (elastomers) are largely used in biomedical applications. However, when damaged, they cannot recover their initial structures and properties. To overcome this limitation and satisfy the requirements of the biomedical field, self-healable hydrogels and elastomers designed using (bio)degradable or bioeliminable polymer chains have been developed and are becoming increasingly popular. This review presents the latest advances in the field of self-healing degradable/bioeliminable networks designed for use in health applications. The strategies used to develop such networks based on reversible covalent or physical cross-linking or their combination via dual/multi-cross-linking approaches are analyzed in detail. The key parameters of these hydrogels and elastomers, such as mechanical properties, repair and degradation times, and healing efficiencies, are critically considered in terms of their suitabilities in biomedical applications. Finally, their current and prospective uses as biomaterials in the fields of tissue engineering, drug/cell delivery, and medical devices are presented, followed by the remaining challenges faced to ensure the further success of degradable self-healable networks.

Bio-Based Reprocessable and Degradable Epoxy Resins via Inverse Vulcanization

“…Several types of degradable epoxy networks are reported using bio-based building blocks. − One popular strategy is by engineering the networks with labile chemical bonds, such as disulfide, acetal, ester, Schiff base, etc. ,− These labile bonds are either inherently existing in the bio-based building components or in situ formed during the cross-linking. , Sometimes, they exhibit dynamic features, allowing the networks to be reprocessed, and are degradable when subjected to specific chemical or thermal treatments. , For example, epoxidized soybean oil (ESO) has been cured by uniquely structured hardeners, bearing a Schiff base bond or a disulfide bond, and the resulting networks can be degraded in an acidic environment or a reducing environment. , A mono-epoxy resin was prepared from vanillin and cross-linked by different diamines via a concomitant amine-epoxy ring opening reaction and Schiff base formation to have varied mechanical and thermal properties . Due to the presence of Schiff base, these epoxy networks were readily degraded in a 0.1 M HCl aqueous solution .…”

Self-healing hydrogels for bone defect repair

“…54,55 Owing to these excellent biological properties, hydrogels have been widely studied in tissue engineering, drug transport, and medical device research. [56][57][58][59][60][61][62] In addition, hydrogels are applied in wound dressings, [63][64][65] electronic equipment, 66 biosensor development, [67][68][69] cell imaging, 70 waste disposal, 71 and articial skin-like materials. [72][73][74] However, a lack of toughness, low mechanical strength and batch variation have limited the application of hydrogels in the medical eld.…”

Dynamic PEG–PLA/Hydroxyurethane Networks Based on Imine Bonds as Reprocessable Elastomeric Biomaterials

“…Multiple reviews have listed the different exchange reactions used in vitrimer materials. – Among those reactions, imine exchange is valuable due to the high exchange rate observed at moderate temperature . Therefore, transimination and imine metathesis have been used for the development of several dynamic networks such as vanillin- or lignin-based polymers – and also in chitosan-based hydrogels, – even if for the latter the term vitrimer was not employed and the characteristic properties of vitrimer materials were not evaluated in details …”

“…7 Therefore, transimination and imine metathesis have been used for the development of several dynamic networks such as vanillin-or lignin-based polymers 20−22 and also in chitosan-based hydrogels, 23−27 even if for the latter the term vitrimer was not employed and the characteristic properties of vitrimer materials were not evaluated in details. 28 In the context of the development of sustainable networks, the replacement of isocyanates in the synthesis of urethanes is a crucial challenge. Indeed, urethanes generally result from the reaction of alcohols and isocyanates.…”