Highly Elastic,Bioresorbable Polymeric Materials for Stretchable,Transient Electronic Systems

Substrates or encapsulants in soft and stretchable formats are key components for transient,bioresorbable electronic systems;however,elastomeric polymers with desired mechanical and biochemical properties are very limited compared to nontransient counterparts.Here,we introduce a bioresorbable elastomer,poly(glycolide-co-ε-caprolactone)(PGCL),that contains excellent material properties including high elongation-at-break(<1300%),resilience and toughness,and tunable dissolution behaviors.Exploitation of PGCLs as polymer matrices,in combination with conducing polymers,yields stretchable,conductive composites for degradable interconnects,sensors,and actuators,which can reliably function under external strains.Integration of device components with wireless modules demonstrates elastic,transient electronic suture system with on-demand drug delivery for rapid recovery of postsurgical wounds in soft,time-dynamic tissues.

Composition Dependence of the Thermal Behavior,Morphology and Properties of Biodegradable PBS/PTMO Segment Block Copolymer

A series of aliphatic biodegradable poly（ether-ester）s based on poly（butylene succinate）（PBS）as hard segment and poly（tetramethylene oxide）（PTMO,M_n=1 000 g/mol） as soft segment were synthesized.The composition dependence of thermal behavior,morphology and mechanical properties was investigated by differential scanning calorimetry（DSC）,atomic force microscopy（AFM）,and tensile testing.The crystallization temperature（T_c） and melting temperature（T_m） of the PBS block within poly（ether-ester）s decrease steadily at first,but decrease sharply with PTMO content above 50 wt%.Two crystallization peaks were detected for PTMO in PBSPTMO60 sample,suggesting the occurrence of fractionated crystallization.The crystallization enthalpies（△H_c） and melting enthalpies（△H_m） of PBS block decrease at first,then increase as PTMO content increases further.AFM has demonstrated that phase-separated morphology transforms from a phase of continuous hard matrix to one of continuous soft matrix containing isolated hard domain as PTMO content is increased.Finally,the results of tensile testing show that the poly（ether-ester）s present the behavior of plastics when PTMO content is below 40 wt%,and of thermoplastic elastomers with PTMO content above 50 wt%.By varying the composition of copolymer,the aliphatic poly（ether-ester）s plastics,or especially biodegradable aliphatic poly（ether-ester）s thermoplastic elastomers can be obtained.

Fast photocurable thiol-ene elastomers with tunable biodegradability,mechanical and surface properties enhance myoblast differentiation and contractile function

Biodegradable elastomers are important emerging biomaterials for biomedical applications,particularly in the area of soft-tissue engineering in which scaffolds need to match the physicochemical properties of native tissues.Here,we report novel fast photocurable elastomers with readily tunable mechanical properties,surface wettability,and degradability.These elastomers are prepared by a 5-min UV-irradiation of thiol-ene reaction systems of glycerol tripentenoate(GTP;a triene)or the combination of GTP and 4-pentenyl 4-pentenoate(PP;a diene)with a carefully chosen series of di-or tri-thiols.In the subsequent application study,these elastomers were found to be capable of overcoming delamination of myotubes,a technical bottleneck limiting the in vitro growth of mature functional myofibers.The glycerol-based elastomers supported the proliferation of mouse and human myoblasts,as well as myogenic differentiation into contractile myotubes.More notably,while beating mouse myotubes detached from conventional tissue culture plates,they remain adherent on the elastomer surface.The results suggest that these elastomers as novel biomaterials may provide a promising platform for engineering functional soft tissues with potential applications in regenerative medicine or pharmacological testing.