In clinic, the application of
photodynamic therapy (
PDT) in deep tissue is severely constrained by the limited penetration depth of visible light needed for activating the
photosensitizer (PS). In this Article, a
merocyanine 540 (MC540) and upconverting nanoparticle (UCN) coloaded functional polymeric
liposome nanocarrier, (MC540 + UCN)/FPL, was designed and constructed successfully for solving this problem in
PDT. Compared with the conventional approaches using UCNs absorbing PSs directly, the combination of UCN and polymeric
liposome has unique advantages. The UCN core as a transducer can convert deep-penetrating near-infrared light to visible light for activating MC540. The functional polymeric
liposome shell decorated with
folate as a nanoshield can keep the UCN and MC540 stable, protect them from being attacked, and help them get into cells. The results show that (MC540 + UCN)/FPL is an individual
nanosphere with an average size of 26 nm. MC540 can be activated to produce
singlet oxygen successfully by upconverting fluorescence emitted from UCNs. After (MC540 + UCN)/FPL was modified with
folate, the cell uptake efficiency increased obviously. More interestingly, in the
PDT effect test, the (MC540 + UCN)/FPL nanocarrier further improved the inhibition effect on
tumor cells by anchoring targeting
folate and transactivating transduction
peptide. Our data suggest that the (MC540 + UCN)/FPL nanocarrier may be a useful nanoplatform for future
PDT treatment in deep-
cancer therapy based on upconversion mechanism.