Metal-Organic Frameworks Derived Carbon Nanoparticles for Photoacoustic Imaging-Guided Photothermal/Photodynamic Combined Therapy.

Combination of photothermal therapy (PTT) and photodynamic therapy (PDT) is a promising cancer treatment in recent years. However, their applications are limited by complex synthetic protocols and low-efficacy. Hence, optimizing experimental approach and improving efficiency of phototherapy is current research focus. In this work, various pyrolysis temperatures and sizes of zeolitic imidazolate framework-8 (ZIF-8) derived carbon nanoparticles (ZCNs) are obtained by a simply direct pyrolysis of ZIF-8 nanoparticles. Meanwhile, the ZCNs can be used as photothermal agents and photosensitizers to produce heat and reactive oxygen species simultaneously upon near infrared laser irradiation. Moreover, it is found out that the phototherapy effects and photoacoustic (PA) signal of ZCNs could be enhanced with the increase of nanoparticle size. Subsequently, guided by PA imaging, the therapeutic effect of ZCNs are investigated on a small animal model, where tumors are entirely eliminated with minimal side effect, demonstrating the high efficacy of larger size of ZCNs through combination of PTT and PDT. Therefore, it is expected that the ZCN is a simple and highly-effective phototherapeutic platform for oncotherapy, and the concept of size dependent enhanced behavior of phototherapy and PA imaging will be very useful in the development of nanomaterials for cancer therapy.