Photo-Driven Delivery of 125I-Labeled Nanomicelles for Nucleus-Targeted Internal Conversion Electron-Based Cancer Therapy.

As a kind of high linear energy transfer (LET) radiation, internal conversion electrons are emitted from some radionuclides, such as 125I, triggering severe DNA damage to tumor cells when transported into the nucleus. Herein, we develop a curcumin-loaded nanomicelle composed of a photosensitizer chlorin e6 (Ce6) and amphiphilic poly(ethylene glycol) (poly(maleic anhydride-alt-1-octadecene)-poly(ethylene glycol) (C18-PMH-PEG)) to deliver 125I into the nucleus under 660 nm laser irradiation, leading to the optimized imaging-guided internal conversion electron therapy of cancer. Ce6-containing nanomicelles (Ce6-C18-PEG) self-assemble with nucleus-targeted curcumin (Cur), obtaining Ce6-C18-PEG/Cur nanoparticles. After labeling Cur with 125I, Ce6-C18-PEG/Cur enables single-photon emission computed tomography and fluorescence imaging of the tumor, serving as a guide for follow-up laser irradiation. Notably, the 660 nm laser-triggered photodynamic reaction of Ce6 optimizes the delivery of Ce6-C18-PEG/125I-Cur at various stages, including tumor accumulation, cellular uptake, and lysosome escape, causing plenty of 125I-Cur to enter the nucleus. By this strategy, Ce6-C18-PEG/125I-Cur showed optimal antitumor efficacy and high biosafety in mice treated with local 660 nm laser irradiation using efficient energy deposition of internally converted electrons over short distances. Therefore, our work provides a novel strategy to optimize 125I delivery for tumor treatment.

Structural characterization and immunological activity of pectin polysaccharide from kiwano (Cucumis metuliferus) peels.

Two novel polysaccharides, namely CMPP-1 and CMPP-2, from kiwano (Cucumis metuliferus) peels were isolated through hot-water extraction, followed by ethanol precipitation and column chromatography. The results showed that CMPP-1 and CMPP-2 were hetero-galacturonans with different molecular weights of 7.35 kDa and 6.90 kDa, respectively. Both of CMPP-1 and CMPP-2 were mainly composed of glucuronic acid (45.93 % and 51.75 %, respectively), and other monosaccharides including rhamnose, arabinose, galactose, glucose, xylose, fucose, mannose, galacturonic acid, and mannuronic acid. The results of structural characterization from FT-IR and NMR confirmed that CMPP-1 and CMPP-2 were pectin with highly branched structure. Furthermore, both CMPP-1 and CMPP-2 possessed immune-enhancing activity and could enhance the secretion of nitric oxide and cytokines (TNF-α, IL-6) in a dose-dependent manner. Especially, CMPP-1 had higher immune activity than CMPP-2 as the minimum effective concentration were 0.78 µg/mL and 6.25 µg/mL, respectively. These findings provide a scientific basis for further utilization of polysaccharide from kiwano peels.

Structural Features of Three Hetero-Galacturonans from Passiflora foetida Fruits and Their in Vitro Immunomodulatory Effects.

Passiflora foetida is a horticultural plant and vital traditional Chinese herbal medicine. In our previous study, the characterization and immuno-enhancing effect of fruits polysaccharide 1 (PFP1), a water-eluted hetero-mannan from wild Passiflora foetida fruits, were investigated. Herein, another three salt-eluted novel polysaccharides, namely PFP2, PFP3, and PFP4, were obtained and structurally characterized. The results showed that PFP2, PFP3, and PFP4 were three structurally similar hetero-galacturonans with different molecular weights of 6.11 × 104, 4.37 × 104, and 3.48 × 105 g/mol, respectively. All three of these hetero-galacturonans are mainly composed of galacturonic acid, galactose, arabinose (75.69%, 80.39%, and 74.30%, respectively), and other monosaccharides including mannose, fucose, glucose, ribose, xylose, and glucuronic acid (24.31%, 19.61, and 25.70%, respectively), although differences in their backbone structure exist. Additionally, immunomodulatory assay indicated that the three hetero-galacturonans possess the ability to promote the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in RAW264.7 macrophages in a concentration-dependent manner (p < 0.05). Especially, PFP3 displayed a stronger enhancing effect than PFP2 and PFP4 at the minimum effective concentration. Therefore, the results suggested that the obtained three salt-eluted hetero-galacturonans, especially PFP3, could be utilized as immunomodulatory effectivity ingredients in nutritional/pharmaceutical industries.