Ferroferric oxide loaded near-infrared triggered photothermal microneedle patch for controlled drug release

The drug release efficiency of microneedle is usually slower than that of oral delivery or hypodermic injection, which severely restricts its widespread use. Herein, a Fe3O4-loaded photothermal microneedle (Fe3O4@MN) patch is developed for controlled drug delivery. Under near infrared (NIR) irradiation, the drug loaded on Fe3O4@MN can be quickly released, achieving an enhanced drug release efficiency.The mechanical property and characterization of Fe3O4@MN were systematically investigated, and the photothermal performance of Fe3O4@MN was also conducted. Moreover, the model-drug-releasing tests and doxycycline hydrochloride releasing tests were carried out to evaluate the drug release performance of Fe3O4@MN under NIR irradiation.Fe3O4@MN has enough mechanical strength to pierce into skins, and the temperature of Fe3O4@MN patch could rapidly increase by 40 ℃ in 1 min under NIR irradiation. In vitro experiment, the release rate of model drug in Fe3O4@MN reached ∼ 80 % in 20 min and the doxycycline hydrochloride release rate of Fe3O4@MN reached ∼ 70 % after 20 min of NIR irradiation, indicating the potential application of the synthesized microneedle patch for transdermal drug delivery. Further penetration test showed that the penetration depth of model drugs carried by Fe3O4@MN patch on the porcine skin under NIR irradiation was 150 - 200 μm longer than that of the patch without Fe3O4 nanoparticles.