Biodegradation of 3D‐printed polylactic acid milliprojections under physiological conditions

Abstract

AbstractThe degradation of 3D‐printed polylactic acid (PLA) milliprojections of different molecular weights and crystallinity was studied under physiological conditions for a few months. The motivation of the work was to investigate the use of such printed materials as a potential release device in a transdermal patch. Upon being subjecting to a degradation environment, the remnant milliprojections were investigated in terms of weight loss and change in molecular weight. The critical molecular weights of the polymers were found to be between 8,000 g/mol and 13,000 g/mol. Among the polymers examined, the amorphous PLA had the fastest rate of degradation, losing almost half of its weight at the end of the study. Differential scanning calorimetry analysis further showed that the onset of degradation was favored in the amorphous regions of the polymers while scanning electron microscopy (SEM) findings suggest enhanced hydrolysis due to greater exposure caused by the increased porosity and crack formation upon reaching the critical molecular weight. Gel permeation chromatography (GPC) showed the emergence of multimodal molecular weight distribution during degradation indicating the fragmentation in the polymer bulk. The results of SEM and GPC analysis suggest that bulk erosion was the main mechanism of degradation of the 3D‐printed models.