Photothermal Heating-Induced Localized Structural Disruption in a Poly-ε-caprolactone Nanocarrier System for Controlled Drug Delivery.

Drug delivery that enables spatial and temporal control is essential to optimal pharmacotherapy, among which photothermal heating has been widely used as a light-responsive drug release. However, the heating mechanism underlying the application has been rarely elaborated. Herein, we used a template-assisted approach to formulate a poly-ε-caprolactone nanocarrier system integrated with magnetic nanoparticles and gold nanorods for a controlled drug delivery. With the incorporated magnetic nanoparticles, the system included efficient cellular internalization via magnetic driving. Meanwhile, it demonstrated a near-infrared-light-responsive on/off drug release behavior by photothermal heating originated from the gold nanorods. The nanostructure of the carrier system was examined intact upon the photothermal heating. A further investigation on the release mechanism showed that the photothermal heating confined temperature elevation to the region around gold nanorods, which only induced a localized structural change of the polymer matrix that triggered the release of the vicinity cargo. The work introduces a feasibly formulated multifunctional drug delivery system, and also, it unveils the controlled release mechanism of the photothermal heating that only triggers a localized structural disruption of the carrier matrix.