Highly porous 3D sponge-like shape memory polymer for tissue engineering application with remote actuation potential

摘要

Shape memory polymers (SMPs) based on poly(epsilon-caprolactone) have been recently investigated in biomedical application field owing to their intrinsic biocompatibility, biodegradability and capacity to undergo shape deformation on exposure to external stimuli. Porous SMPUs prepared by electrospinning technique are usually 2D structures not appropriate for cell proliferation. In this study, an attempt has been made to manufacture a 3D SMP scaffold using self-assembly electrospinning and simultaneous photo-crosslinking. A detailed investigation disclosed that suitable crosslinking between SMP chains, conductivity of the solution, and concentration of components play major role in fabricating 3D scaffold. Gold nanoparticles (GNPs) of 10-nm diameter were impregnated in 3D porous structure to cause remote actuation by infrared irradiation or magnetic field application for further studies. Results of scanning electron microscopy and transmission electron microscopy showed a highly porous structure with uniform distribution of GNPs. Sponges had an average porosity of 93 +/- 1.8%, demonstrating super-high absorption capacity. Thermal characterization performed using DSC and TGA demonstrated that the switching temperatures of the shape memory composites were near to body temperature and the degradation temperatures of the scaffolds were high enough for thermal stability. Cyclic, thermomechanical tensile tests revealed that the 3D scaffolds had good shape-memory (SM) properties with strain recovery rates of 88-98% and strain fixity rates up to 97% (after the fourth cycle), when deformations were attenuated at the body temperature range. Cytocompatibility evaluation using NIH3T3 cells showed non-toxic behavior suggesting that the GNPs incorporated scaffolds could be employed as 3D scaffolds for bio-applications.