Tailored Core-Shell Nanocarrier for Therapeutic Drug Delivery via Visible Light Activation

Abstract

We present a novel drug delivery nanocarrier consisting of 300 nm-sized POT/Fe3 O 4 /TRZ+TPB− nanoparticles(NPs). The mechanism is based on the (photo)oxidation of poly(3-octylthiophene-2,5-diyl) (POT) (from POT 0 to POT+),which facilitates the release of the positively charged drug trazodone (TRZ+) encapsulated in the NPs. The primaryfactor guiding the overall process is the maintenance of the electroneutrality condition in each NP. The incorporationof a Fe 3 O 4 element enables the formation of an organic-inorganic heterojunction (Fe3 O 4 /POT) in the core of the NP. Thisheterojunction permits us to utilize visible light to induce the POT photooxidation to trigger the release of TRZ+, unlikeother platforms based on a more energetic illumination requirement. The developed nanocarrier allows for a controlleddrug release, achieving doses of 3.5 µg mL−1 of TRZ under 530 nm irradiation, 2.4 µg mL−1 at 625 nm, and 1.6 µg mL−1at 470 nm within 1 h. The delivery is tested in undiluted blood serum, achieving an efficiency exceeding 90%. Overall,the integration of magnetic properties with a conductive polymer along with the adjustment of the band gap to enhancephotooxidation performance in the visible range, constitute the conceptual innovation behind the controlled drug deliverysystem here presented, with TRZ as a model.