Adipose-derived mesenchymal stem cell-loaded ß-chitin nanofiber hydrogel promote wound healing in rats.

Because of stem cells are limited by the low efficiency of their cell homing and survival in vivo, cell delivery systems and scaffolds have attracted a great deal of attention for stem cells' successful clinical practice. ß-chitin nanofibers (ß-ChNF) were prepared from squid pens in this study. Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy proved that ß-ChNFs with the diameter of 5 to 10 nm were prepared. ß-ChNF dispersion became gelled upon the addition of cell culture medium. Cell culture experiments showed that ß-ChNFs exhibited negligible cytotoxicity towards ADSCs and L929 cells, and it was found that more exosomes were secreted by the globular ADSCs grown in the ß-ChNF hydrogel. The vivo experiments of rats showed that the ADSCs-loaded ß-ChNF hydrogel could directly cover the wound surface and significantly accelerate the wound healing and promote the generation of epithelization, granulation tissue and collagen. In addition, the ADSCs-loaded ß-ChNF hydrogel clearly regulated the expressions of VEGFR, α-SMA, collagen I and collagen III. Finally, we showed that ADSCs-loaded ß-ChNF hydrogel activated the TGFß/smad signaling. The neutralization of TGFß markedly reduced Smad phosphorylation and the expressions of TIMP1, VEGFR and α-SMA. Taken together, these findings suggest that ADSCs-loaded ß-ChNF hydrogel promises for treating wounds that are challenge to heal via conventional methods. Graphical abstract.

Efficient Cancer Regression by a Thermosensitive Liposome for Photoacoustic Imaging-Guided Photothermal/Chemo Combinatorial Therapy.

The capacity to specifically destroy cancer cells while avoiding normal tissue is urgently desirable in cancer treatment. Herein, a photothermal-trigger-released system serves as a photoacoustic imaging agent constructed by entrapping diketopyrrolopyrrole-based conjugated polymers and curcumin in a poly(ethylene glycol) (PEG)-protected thermoresponsive liposomal phospholipid bilayer. This lipid nanostructure can improve the bioavailability of hydrophobic agents for photothermal treatment with high efficiency and deliver the anticancer drug curcumin to the tumor site actuated by near-infrared (NIR) irradiation. A significantly enhanced combined therapeutic effect to HepG2 tumor-bearing mice was acquired in contrast to the result of single therapy alone. These liposomes with the capability of photoacoustic imaging, greater EPR-induced accumulation in tumor sites, and hyperthermia ablation for photothermal chemotherapy show potential for photoacoustic imaging-guided photothermal/chemo combined therapeutic applications.

Anti-biofilm Activities from Bergenia crassifolia Leaves against Streptococcus mutans.

Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. The bacteria can produce glucosyltransferases (Gtfs) to synthesize extracellular polysaccharides (EPSs) that are known as virulence factors for adherence and formation of biofilms. Therefore, an ideal inhibitor for dental caries is one that can inhibit planktonic bacteria growth and prevent biofilm formation. Bergenia crassifolia (L.), widely used as a folk medicine and tea beverage, has been reported to have a variety of bioactivities. The present study aimed to explore the effect of B. crassifolia (L.) leaf extracts on the biofilm of Streptococcus mutans. The B. crassifolia (L.) leaf extracts showed inhibitory effects by decreasing viability of bacteria within the biofilm, as evidenced by the XTT assay, live/dead staining assay and LDH activity assay, and could decrease the adherence property of S. mutans through inhibiting Gtfs to synthesize EPSs. In addition, the reduced quantity of EPSs and the inhibition of Gtfs were positively correlated with concentrations of test samples. Finally, the MTT assay showed that the extracts had no cytotoxicity against normal oral cells. In conclusion, the extracts and sub-extracts of B. crassifolia leaves were found to be antimicrobial and could reduce EPS synthesis by inhibiting activities of Gtfs to prevent bacterial adhesion and biofilm formation. Therefore, B. crassifolia leaves have potential to be developed as a drug to prevent and cure dental caries.