Gold nanoparticles gated mesoporous carbon with optimal particle size for photothermal-enhanced thermochemotherapy

Abstract

Mesoporous carbon nanoparticles (MCNs) have been widely used in tumor photothermal therapy. Herein, MCNs with different particle sizes (100 nm, 400 nm and 500 nm) were fabricated in our work by controlling the ethanol amounts to evaluate their photothermal conversion performance. Rationally, small-sized MCNs with the highest photothermal conversion efficiency were selected as the drug-loading carriers. Subsequently, the spherical gold nanoparticles with the same size (4 nm) as the mesopores of MCNs were modified on the opening of MCNs as the gated switches, which could not only achieve the redox-responsive controlled release of anticancer drugs at tumor location, but also realize the photothermal-enhanced synergetic thermochemotherapy under a low power irradiation. Meanwhile, the photothermal conversion efficiency (η) of MCN-Au was 31.2 %, which was higher than that of MCNs (η = 28.3 %). DOX release increased significantly under the condition of high concentration of GSH, low pH and NIR, suggesting that the delivery platform was characterized by multi-responsive drug release. In addition, the combined therapeutic index of DOX/MCN-Au was 0.509, proving that the combination group of thermochemotherapy had the highest cell killing ability. Meanwhile, confocal laser scanning microscopy (CLSM) showed that DOX/MCN-Au had an increased cellular uptake efficiency under NIR irradiation. In summary, the constructed DOX/MCN-Au system was expected to show a clinical treatment potential for synergistic thermochemotherapy of tumors.