Self-assembled
hyaluronic acid (HA) nanoparticles have been extensively
investigated as anticancer therapeutic agents due to the biocompatibility,
biodegradability, and active targeting characteristics of HA. However,
many HA nanoparticles are restricted to the applications in drug delivery
for chemotherapy or lack effective imaging agents. Hence, we developed
the camptothecin (CPT)-loaded HA-SS-BFVPBT nanoparticles (HSBNPs)
as a multifunctional platform for two-photon imaging and synergistic
chemo-photodynamic therapy at the same time. A novel conjugated oligomer
photosensitizer, BFVPBT, which was conjugated onto HA through the
redox-responsive disulfide linkage (SS), could not only provide a
hydrophobic domain for the formation of nanoparticles and drug entrapment
but also act as a two-photon photosensitizer that can be directly
excited and simultaneously used in two-photon imaging and photodynamic
therapy (PDT). HeLa cells overexpressing the HA receptor (CD44) were
used for in vitro studies, which proved the specific
cellular uptake of CPT-loaded HSBNPs and excellent two-photon PDT/chemotherapy
synergistic effect. The nanoparticles have also been shown to realize
tumor-targeting in vivo imaging in HeLa-tumor-bearing
mice. Moreover, the fluorescence of CPT-loaded HSBNPs could be activated
due to the degradation by the reductive glutathione (GSH) and overexpressed
hyaluronidases (Hyal-1) in cancer cells, and the intracellular drug
release rate was quickened, thus improving the probability of precise
cancer diagnosis and therapy. Accordingly, this HSBNPs system is also
anticipated to be a precise nanocarrier for other imaging and therapeutic
agents besides CPT, offering a promising new avenue for imaging-guided
efficient cancer therapy.