Photothermal therapy (PTT) has been widely studied for
tumor therapy. However, the clinical transformation of PTT has encountered significant challenges in
tumor recurrence, because the uneven
hyperthermia in
tumor tissues can result in the survival of
cancer cells in the lower temperature regions close to blood vessels (as the blood flow can dissipate the localized heat). It is therefore important for clinical treatments to retain the excellent therapeutic efficiency of PTT at relatively low temperatures. In this article, innocuous hollow mesoporous
carbon spheres (HMCS) with a high photothermal conversion efficiency were obtained by a one-pot synthesis method. After modification with
DSPE-PEG, the HMCS-PEG exhibited a superior stability in biomedia, which is beneficial for further biological applications. Interestingly, combined with hydrophobic
gambogic acid (GA) which can downregulate
heat shock protein 90 (HSP90), the HMCS-PEG-GA system showed a significant NIR-enhanced
tumor therapeutic effect in vitro and in vivo under mild temperature conditions (∼43 °C), and the combination index (CI) value of HMCS-PEG-GA was found to be 0.72. Meanwhile, this nano-system possessed good photothermal imaging and photoacoustic imaging abilities. Guided by the photoacoustic imaging signal, HMCS-PEG-GA showed enormous potential for use in accurate
tumor diagnosis and mild-temperature PPT treatment applications, which is very important for clinical transformation of this nano-system.