Label-Free Fluorescent Mesoporous Bioglass for Drug Delivery, Optical Triple-Mode Imaging, and Photothermal/Photodynamic Synergistic Cancer Therapy

Nanomaterials combined with phototherapy and multimodal imaging are promising for cancer theranostics. Our aim is to develop fluorescent mesoporous bioglass nanoparticles (fBGn) based on carbon dots (CD) with delivery, triple-mode imaging, and photothermal (PTT) properties for cancer theranostics. A direct and label-free approach was used to prepare multicolor fluorescent fBGn with 3-aminopropyl triethoxysilane as the surface-functionalizing agent. The calcination at 400 °C provided fBGn with high fluorescence intensity originating from the CD. In particular, a triple-mode emission [fluorescence imaging, two-photon (TP), and Raman imaging] was observed which depended on CD nature and surface properties such as surface oxidation edge state, amorphous region, nitrogen passivation of surface state, and crystalline region. The fBGn also exhibited phototherapeutic properties such as photodynamic (PDT) and PTT effects. The antitumor effect of the combined PDT/PTT therapy was significantly higher than that of individual (PDT or PTT) therapy. The fBGn, due to the mesoporous structure, the anticancer drug doxorubicin could be loaded and released in a pH-dependent way to show chemotherapy effects on cancer cells. The in vivo imaging and biocompatibility of fBGn were also demonstrated in a nude mouse model. The fBGn, with the combined capacity of anticancer delivery, triple-mode imaging, and PTT/PDT therapy, are considered to be potentially useful for cancer theranostics.