Trials of a drug release platform in near-spherical porous NiTi alloys containing a thermosensitive hydrogel as the inner coating†

Abstract

This study presents a preliminary investigation of porous nickel-titanium (NiTi) materials with controllable porosity fabricated through metal injection molding combined with the powder space-holder method (MIM-PSH). The thermosensitive hydrogel Pluronic F-127 was utilized as a drug carrier to load the anti-proliferative drug rapamycin, resulting in porous NiTi-hydrogel composite materials for controlled drug release. By tuning the NiTi matrix porosity (0%, 20%, and 40%), the system achieved precise modulation of drug loading capacity and release kinetics. Notably, the 40% porous NiTi composite exhibited a threefold increase in the drug-loading capacity and sustained release over 17 days. This hybrid design leveraged the thermoresponsive properties of the hydrogel and the tailored pore architecture to enable spatiotemporal control of rapamycin delivery, effectively inhibiting human aortic smooth muscle cell proliferation and mitigating in vivo vascular tissue hyperplasia. This study provides a foundational framework for the development of multifunctional biomaterial systems for vascular therapy.