Abstract
Drug-eluting stents used to inhibit granulation tissue hyperplasia after tracheal stent implantation rely on passive drug release mechanisms, which make precise controlled release difficult and may lead to either insufficient efficacy or toxic side effects. This study aims to design a piezoelectric effect-based adaptive drug-releasing film for tracheal stents, capable of self-regulating the release of anti-inflammatory drugs according to the mechanical changes in the pathological environment within the patient's airway. First, a polyvinylidene fluoride piezoelectric film was prepared on a metal stent surface via electrospinning. Curcumin-loaded poly(3,4-ethylenedioxythiophene) conductive nanoparticles were dispersed in a polyvinyl alcohol hydrogel and adhered to the upper and lower edges of the stent (prone to hyperplasia areas). Experiments showed uniform nanoparticle morphology with a curcumin loading rate of (12.6 ± 1.80)%. Electrochemical tests indicated that the curcumin release rate was highest (approximately 90%) at a reduction potential of -1.5 V, and "on/off" controlled release could be achieved through intermittent electrical stimulation. When periodic pressure was applied to the film, its output voltage increased with loading speed (up to -8 V). Furthermore, the curcumin release rate was positively correlated with the pressure speed, reaching a cumulative release of about 15% within 48 h at a loading speed of 2.5 m/min. The drug-loaded piezoelectric film-covered stent developed in this study successfully achieves mechanically controlled release of the anti-inflammatory drug curcumin under intermittent cyclic pressure, providing an effective strategy for developing intelligent tracheal stents with adaptive and controllable drug release.