PTT
PTT is a viable alternative to conventional cancer treatment since it is non-invasive, has high spatiotemporal controllability, and few unfavorable side effects[21]. NIR light-reacting photothermal agents (PTAs) are the best for performing PTT on cancer. The development of novel PTAs for tumor treatment and eradication is currently undergoing significant research[14]. Luet al. developed multifunctional nanoparticles based on polydopamine (PDA) for combining immunoadjuvant R848 to achieve FL and multispectral optoacoustic tomography (MSOT) dual-mode imaging for diagnostic purposes[26]. PDA-PEG-R848-CDs can be employed for NIR-induced PTT to eradicate distant/metastatic cancers by directly eliminating original tumor cells and inducing immune responses[26]. Further, PDA-PEG-R848-CD-based PTT combined with PD-L1 blockers would create a long-term immunological memory effect that could be used to prevent tumor recurrences[26]. Qian et al. effectively used a hydrogen bond/electrostatic-assisted co-assembly approach to consistently incorporate polymer-coated CDs into the ordered framework of mesoporous silica nanoparticles (CD@MSNs)[27]. The obtained CD@MSN was capable of accumulating dispersive CDs with enhanced photothermal effect and elevated targeting accumulation, which allowed for photothermal imaging-guided PTT both in vitro and in vivo [27]. It is interesting to note that CD@MSN-mediated PTT, which takes advantage of the biodegraded debris, has been shown to synergistically achieve immune-mediated inhibition of tumor metastasis by promoting the proliferation and activation of macrophages and NK cells while also increasing the secretion of relevant cytokines[27] (Figure 1b). Lu et al. reported a kind of Z-scheme CDs-based PTAs consisting of two-dimensional (2D) ultrathin nonmetallic BxC/C Janus quantum sheets (BxC/C JQSs) which have a high photothermal conversion of 60% in NIR-II[28]. In addition, these new Z-scheme BxC/C-polyethylene glycol JQSs display effective tumor elimination outcomes both in vitro and in vivo through the synergistic photothermal-immunotherapy in the NIR-II with undetectable harm to normal tissues[28]. To sum up, these studies showed the potential of combining PDA-based PTT with cancer immunotherapy to achieve a remarkable synergistic therapeutic result in tumor treatment.