Composite-dissolving microneedle patches for chemotherapy and photothermal therapy in superficial tumor treatment

A combination of chemotherapy and photothermal therapy (PTT) has emerged as a promising strategy for cancer therapy. To ensure that the chemotherapeutic drug and photothermal agent can be simultaneously delivered to the tumor site to exert their synergistic effects, a safe and efficient delivery system is needed. Herein, we fabricated doxorubicin hydrochloride (DOX)- and indocyanine green (ICG)-loaded microneedle (MN) patches (PVP@DOX/MSN@ICG) using a two-step casting process. Mesoporous silica nanoparticles (MSNs) were used to improve the ICG stability and avoid reducing its PTT efficiency in vivo. The MN patches exhibited a good skin penetration ability, and the tips of the MN patches were dissolved by the interstitial fluid to release DOX and ICG at the tumor sites. Under 808 nm laser irradiation within 2 min, the local temperature in the tumor quickly reached 48 °C at a low power of 0.34 W cm-2. A combination of chemotherapy and PTT for PVP@DOX/MSN@ICG MN patches may maximally induce human osteosarcoma MG-63 cells in vitro. Moreover, the in vivo results showed that PVP@DOX/MSN@ICG MN patches had the best antitumor effects because of synergistic chemotherapy and PTT. Therefore, the composite-dissolving MN patch is a promising strategy for enhancing the antitumor effect of chemotherapy alone and shows the potential for the synergistic therapy of superficial tumors.