MC540 and Upconverting Nanocrystal Coloaded Polymeric Liposome for Near-Infrared Light-Triggered Photodynamic Therapy and Cell Fluorescent Imaging

Abstract

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.

Upconversion Nanoparticles for Light-Activated Therapy

“…However, the average size of nanoclusters increased to 340 nm after the selfassembly process. By contrast, PS-UCNP composites in the former two reports [87,88] still dispersed as individuals with small particle sizes (<30 nm).…”

“…Very recently, Chang et al [88] encapsulated MC540 and NaYF 4 :Yb/Er UCNPs into octadecyl-quaternized lysine-modified chitosan (OQLCS) liposome via this evaporation method. FA and TAT peptide were also employed to enhance the targeting ability and cell uptake efficiency.…”

Efficient up-conversion in Yb:Er:NaT(XO4)2 thermal nanoprobes. Imaging of their distribution in a perfused mouse

“…Within this approach, NPs with up-conversion (UC) properties are recognized fluorescence nanoprobes because they are free of photobleaching shown by organic dyes [1] or photoblinking of semiconductor quantum dots,[2] and their excitation in the near infrared (NIR) circumvent the problem of undesired tissue and cell autofluorescence typically observed under ultraviolet/blue photoexcitation. [3] Therefore, UCNPs have been extensively proposed for thermal nanosensing,[4,5] optical nanoencoding,[6] photocatalysis,[7] subcutaneous photodynamic therapy,[8,9] biosensing,[10] cancer cell recognition and treatment,[11] intracellular drug delivery,[9,12] as well as for in vitro and in vivo biomedical imaging. [9,13,14]…”

Novel Fluorinated Polymer-Mediated Upconversion Nanoclusters for pH/Redox Triggered Anticancer Drug Release and Intracellular Imaging

“…Lanthanide‐based upconversion nanoparticles (UCNPs) have been widely investigated for biological applications, including bioimaging, biomolecular sense, and photodynamic therapy, because they can provide visible or near‐infrared emission under excitation at 980 nm wavelength and exhibit excellent chemical, biological, and optical properties, such as low cytotoxicity, narrow emission lines, large anti‐Stokes shifts, high penetration depth in tissues, and high resistance to photobleaching . The most efficient host matrix of UCNPs is NaYF 4 codoped with Yb 3+ as a sensitizer, and Er 3+ or Tm 3+ as emitter.…”