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.