Mussel-inspired adhesive and polypeptide-based antibacterial thermo-sensitive hydroxybutyl chitosan hydrogel as BMSCs 3D culture matrix for wound healing.

Hydrogels have gained great attentions as wound dressing. Binding to the tissue and preventing wound infection were the basic requirements for an "ideal dressing". We employed l-DOPA and ε-Poly-l-lysine to modify thermo-sensitive hydroxybutyl chitosan (HBC) to obtain (l-DOPA) - (ε-Poly-l-lysine)-HBC hydrogels (eLHBC). The eLHBC exhibited an almost 1.5 fold (P < 0.01) increase in wet adhesion strength compared to HBC. Upon the introduction of ε-Poly-l-lysine, eLHBC presented inherent antimicrobial property and prevented wound infection and inflammation response. Bone marrow mesenchymal stem cells (BMSCs) encapsulated in the eLHBC (BMSCs ⊂ eLHBC) could secret cytokins and growth factors via paracrine and promote the migration of fibroblast cells. BMSCs ⊂ eLHBC enhanced the complete skin-thickness wound healing via promoting collagen deposition and inhibiting infection and inflammation in vivo with wound closure rate being above 99 % after 15 days. The bioinspired, tissue-adhesive eLHBC could serve as advanced wound dressings for facilitating tissue repair and regeneration.

Mussel-inspired antibacterial polydopamine/chitosan/temperature-responsive hydrogels for rapid hemostasis.

The aim of this study was to develop an effective wound dressing using a temperature-responsive hydroxybutyl chitosan (HBC) based hydrogel. The HBC - chitosan (CS) - dopamine (HCS-DOPA) composite hydrogels were prepared by the dopamine self-polymerization at different concentrations (0, 0.5, 1.0 and 2.0 mg/mL), termed as HCS, HCS-DOPA-0.5, HCS-DOPA-1 and HCS-DOPA-2, respectively. The gelling characteristic of HBC hydrogel was not influenced by composite CS and DOPA. The HCS-DOPA composite hydrogels were non-cytotoxic to mouse fibroblast cells (L929), and induced under 5.0% hemolysis rate. In vitro antibacterial studies, composite HCS-DOPA-2 hydrogels exhibited lasting inhibition to S. aureus >8 h. The whole blood test in vitro demonstrated that blood clotting time treated with HCS-DOPA-2 composite hydrogels was shortened to 95.6 s compared with that of HCS in vitro hemostasis. The results suggested that HCS-DOPA-2 composite hydrogels could be applied as a promising wound dressing for hemostasis in vitro.

Inducing sustained release and improving oral bioavailability of curcumin via chitosan derivatives-coated liposomes.

Liposomes (LPs), a delivery vehicle for stabilizing drugs, the characteristics of being easy to aggregate and fuse limit its application. Polymer coating is a promising way to tackle these issues. In this study, the potential of carboxymethyl chitosan (CMCS) and quaternary ammonium chitosan (TMC)-coated liposomes (CMCS/TMC-LPs) for improving the oral delivery capacity of curcumin (CUR) was explored. CMCS/TMC-LPs were prepared by electrostatic adsorption in a layer-by-layer manner. CMCS/TMC-LPs were spherical and had not obvious change in particle size and morphology after storage at 4 °C for 7 and 14 days. CMCS/TMC-LPs possessed favorable gastric acid tolerance (the cumulative drug release rate <10%) due to stable structure. The hemolysis test and Cell Counting Kit-8 (CCK8) assay appeared satisfactory biocompatibility of CMCS/TMC-LPs. The pharmacokinetics exhibited that oral absolute bioavailability of CUR loaded CMCS/TMC-LPs was about 38%, which was around 6 folds and 3 folds higher than CUR loaded LPs and CUR loaded TMC-LPs, respectively. The in vivo experiments showed that CMCS/TMC-LPs could prolong the retention time of CUR in systemic circulation and generate high level of CUR in liver, spleen and lung. Thus, CMCS/TMC-LPs may be a promising carrier for improving the efficacy and safety of orally administered drugs.

The temperature-responsive hydroxybutyl chitosan hydrogels with polydopamine coating for cell sheet transplantation.

The aim of this study was to develop an effective cell sheet translocation method using a cell adhesive and temperature-responsive hydroxybutyl chitosan hydrogel (HBC). The polydopamine (PD)-coated HBC hydrogels were prepared by the dopamine self-polymerization on the surface of HBC hydrogel with different coating time, termed as P30, P60 and P120, respectively. Gelling property of HBC was not affected by PD coating. The PD-coated HBC hydrogels promoted the attachment and proliferation of mouse fibroblast cells (L929) and human umbilical vein endothelial cells (HUVECs), and allowed formation of monolayer cell sheet. In vitro translocation of HUVECs sheet could be obtained successively through phase transition of PD coated HBC hydrogel from gel to sol, and the cells sheet transferred from P30 hydrogel to a round cell coverglass maintained relatively complete monolayer and normal cell morphology. The results showed that P30 hydrogel has the potential to be used for cell transplantation therapy.

[Impacts of ultraviolet irradiation on the sperm motility and longevity of Acipenser baerii].

This paper studied the impacts of different dose ultraviolet irradiation (254 nm, UVC) on the sperm motility and longevity of Acipenser baerii. Ultraviolet irradiation had significant impacts on the sperm motility, its fast motion time, and longevity. With the increasing dose of ultraviolet irradiation, the sperm motility decreased rapidly first, increased rapidly then, and decreased rapidly again. The sperm fast motion time had the similar variation trend as the sperm motility, but the sperm longevity kept decreasing with increasing dose of ultraviolet irradiation. When the ultraviolet irradiation dose increased to 288 mJ x cm(-2), the sperm fast motion disappeared; when the ultraviolet irradiation dose increased up to 324 mJ x cm(-2), the sperm had no motility and died. According to the "Hertwig effect", the optimum ultraviolet irradiation dose for inactivating A. baerii sperm was 216 mJ x cm(-2).

[Effects of storage medium and temperature on short-term storage of Acipenser baerii eggs].

This paper studied the effects of different storage medium (coelomic fluid, Hepes solution, and modified Ringer's solution), temperature (4 degrees C and 16 degrees C), and duration (4 h, 8 h, 16 h, and 24 h) on the short-term storage of Siberian sturgeon (Acipenser baerii) eggs. The results showed that storage medium, temperature, and duration all had significant effects on the fertilization rate, hatching success, and malformation of newly hatched larvae (P < 0.05). With the increase of storage duration, the fertilization and hatching rates decreased, while the malformation rate of hatched larvae increased. The A. baerii eggs stored at 16 degrees C had higher fertilization, hatching, and malformation rates but shorter holding time than those stored at 4 degrees C. The optimal conditions for the short-term storage of A. baerii eggs were Hepes solution prepared according to the biochemical composition of A. baerii coelomic fluid, 16 degrees C, and 4 h, under which, 86.36% fertilization rate, 94.74% hatching rate, and zero malformation would be obtained.

[Effects of initial feeding on the growth, survival, and body biochemical composition of Siberian sturgeon (Acipenser baerii) larvae].

Siberian sturgeon (Acipenser baerii) larvae were raised with Limnodrilus sp., Artemia nauplii, Moina sp., and artificial commercial diet for 30 days to investigate the effects of different initial feeding diets on the growth, survival, and body biochemical composition of the larvae. The results showed that A. nauplii was the best initial feeding diet, with the survival rate of A. baerii larvae being significant higher (96.67%) than the others. Feeding with Limnodrilus sp. gave the highest growth rate of A. baerii larvae, while feeding with artificial commercial diet gave the lowest efficiency on the growth rate and survival rate of the larvae. The larvae raised with different diets had significantly different body biochemical composition. After fed with artificial commercial diet, the larvae had the highest moisture content but the lowest crude protein and crude ash contents. Taking A. nauplii as the initial feeding diet and then feeding with Limnodrilus sp. could gave the ideal growth and survival rates of A. baerii larvae.