Effects of Chemical Composition on the Shape Memory Property of Poly(dl-lactide-co-trimethylene carbonate) as Self-Morphing Small-Diameter Vascular Scaffolds

Abstract

Smart materials have great potential in many biomedical applications, in which biodegradable shape memory polymers (SMPs) can be used as surgical sutures, implants, and stents. Poly(DL-lactide-co-trimethylene carbonate) (PDLLTC) represents one of the promising SMPs and is widely used in biomedical applications. However, the relationship between its shape memory property and chemical structure has not been fully studied and needs further elaboration. In this work, PDLLTC copolymers in different compositions have been synthesized, and their shape memory properties have been investigated. It has been found that the shape memory property is related to the chemical composition and polymeric chain segments. The copolymer with a DLLA/TMC ratio of 75:25 (PDLLTC7525) has been demonstrated with great shape fixation and recovery ratio at human body temperature. Furthermore, PDLLTC7525-based self-morphing small-diameter vascular scaffolds adhered with inner electrospun aligned gelatin/hyaluronic acid (Gel/HA) nanofibers have been constructed, as a merit of its shape memory property. The scaffolds have been demonstrated to facilitate the proliferation and adhesion of endothelial cells on the inner layer. Therefore, PDLLTC with tailorable shape memory properties represents a promising candidate for the development of SMPs, as well as for small-diameter vascular scaffolds construction.

Reconfigurable scaffolds for adaptive tissue regeneration

“…Thermoresponsive SMPs are representative examples that have been commonly used in forming reconfigurable scaffolds whose shapes could undergo spontaneous transformations upon being placed in physiological environments at body temperature. [31][32][33][34][35][36][37] Some SMPs and hydrogels whose shapes could be deformed upon hydration have also provided candidates for fabricating one-way reconfigurable scaffolds to be triggered by bio-fluids abundant within human bodies. 44,54 Besides, enzyme-responsive SMPs would be promising for forming reconfigurable scaffolds enabling spontaneous shape transformations in specific pathophysiological environments within a relatively long time period (∼7 days).…”

“…31 A PLA-based copolymer, poly( d , l -lactide- co -trimethylene carbonate) (PDLLA- co -TMC) with tuneable T g in the range from 20–45 °C, has been used for preparing reconfigurable nanofibrous scaffolds via electrospinning for bone and vascular tissue engineering. 32,33 Such copolymers could also be suitable for extrusion-based 3D printing, 34 subsequently forming porous scaffolds with initially customized geometries. 35 The polymer blends, such as poly( l -lactic acid) (PLLA)/PCL–diacrylate and PU/gelatin, could also be simply processed to be porous scaffolds via salt leaching or extrusion-based low-temperature 3D printing, which showed semi-interpenetrating networks and excellent shape-memory effects that could be actuated by body temperature.…”