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.