NIR-responsive shape memory composite nanofibers as deployable matrices for biomedical applications

Abstract Shape memory polymers (SMPs) and shape memory composites have gained tremendous attention in recent times due to their unique ability to switch physical shapes and properties upon external stimulation. Electrospinning SMPs into three-dimensional nanofibrous mats renders them useful for a variety of applications, spanning textiles, smart wearables, scaffolding for tissue repair, soft robotics, wound healing, etc. However, SMP nanofibers responsive to contactless stimulation are scarcely reported. In this work, an SMP, namely polylactide-co-trimethylene carbonate (PLMC) nanoengineered with iron oxide (Fe 3 O 4 ) particles, was fabricated into composite nanofibrous mats via a one-step electrospinning method for near-infrared (NIR)-based heating at physiological temperatures. NIR-mediated heating results from the photothermal capabilities of the Fe 3 O 4 particles. Defect-free composites were fabricated by electrospinning. Scanning electron microscopy revealed nanofibrous architectures. The filler content (1, 2, or 5% w/w) of Fe 3 O 4 in PLMC fibers was varied. The physicochemical properties of PLMC-Fe 3 O 4 composite nanofibrous mats were characterized using differential scanning calorimetry, Fourier transform infrared spectroscopy, mechanical testing, and NIR-assisted shape recovery measurements. While 1% did not yield noticeable shape recoveries, both 2% and 5% resulted in >95% shape recovery. The four-dimensional fabricated composite nanofibers are endowed with excellent and tunable shape recovery properties under NIR. Shape memory fiber mats developed here can be applied for diverse applications that require benign, spatiotemporally controlled, and non-contact stimulation.