Phototherapy,
such as photodynamic therapy (PDT) and photothermal
therapy (PTT), refers to the therapeutic strategy using a visible
or near-infrared (NIR) laser to generate free radicals or heat for
noninvasive and localized tumor treatment. However, limited by the
low photoconversion efficiency of therapeutic agents, a single treatment
method can hardly lead to complete tumor ablation, even when enhancing
the power density of the laser and/or prolonging the irradiation duration.
In this work, copper ion and ruthenium complex codoped polydopamine
nanoparticles (Cu(II)/LRu/PDA NPs) are designed for PDT/PTT dual-mode
therapy. The doped LRu in the NPs can generate reactive oxygen species
under visible laser irradiation and enable PDT. Because of the strong
absorption in the NIR region, PDA can not only generate heat for PTT
under irradiation but also be used for photoacoustic tomography (PAT)
imaging. Meanwhile, the doping of Cu(II) in the NPs through the coordination
with PDA facilitates T1-weighted magnetic resonance imaging
(MRI). Thus, MR/PAT imaging-guided PDT/PTT dual-mode therapy is achieved.
The in vivo experiments indicate that the Cu(II)/LRu/PDA NPs can accumulate
in HeLa tumors with a retention rate up to 8.34%ID/g. MR/PAT imaging
can clearly identify the location and boundary of the tumors, permitting
precise guidance for phototherapy. Under the combined effect of PDT
and PTT, a complete ablation of HeLa tumors is achieved. The current
work provides an alternative nanoplatform for performing PDT/PTT dual-mode
therapy, which can be further guided by MR/PAT imaging.