Multifunctional chitin-based barrier membrane with antibacterial and osteogenic activities for the treatment of periodontal disease.

The guided tissue regeneration technique is an effective approach to repair periodontal defect. However, collagen barrier membranes used clinically lose stability easily, leading to soft tissue invasion, surgical site infection, and failure of osteogenesis. An ideal barrier membrane should possess proper antibacterial, osteoconductive activities, and favorable biodegradation. In this study, zinc oxide nanoparticles were homogeneously incorporated into the chitin hydrogel (ChT-1%ZnO) through one-step dissolution and regeneration method from alkaline/urea solution the first time. The remaining weights of ChT-1%ZnO in 150 µg/mL lysozyme solution was 52% after 5 weeks soaking. ChT-1%ZnO showed statistical antibacterial activities for P. gingivalis and S. aureus at 6 h, 12 h, and 24 h. Moreover, ChT-1%ZnO exhibits osteogenesis promotion in vitro, and it was further evaluated with rat periodontal defect model in vivo. The cemento-enamel junction value in ChT-1%ZnO group is 1.608 mm, presenting a statistical difference compared with no-membrane (1.825 mm) and ChT group (1.685 mm) after 8 weeks postoperatively.

Alginate-chitosan oligosaccharide-ZnO composite hydrogel for accelerating wound healing.

Moist, breathable and antibacterial microenvironment can promote cell proliferation and migration, which is beneficial to wound healing. Here, we fabricated a novel sodium alginate-chitosan oligosaccharide­zinc oxide (SA-COS-ZnO) composite hydrogel by spontaneous Schiff base reaction, using aldehydated sodium alginate (SA), chitosan oligosaccharide (COS), and zinc oxide (ZnO) nanoparticles, which can provide a moist and antibacterial environment for wound healing. The porosity and swelling degree of SA-COS-ZnO hydrogel are 80% and 150%, respectively, and its water vapor permeability is 682 g/m2/24h. The composite hydrogel showed good biocompatibility to blood cells, 3T3 cells, and 293T cells, and significant antibacterial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and Bacillus subtilis. Moreover, the hydrogel showed a promoting effect on wound healing in a rat scald model. The present study suggests that marine carbohydrates composite hydrogels are promising in wound care management.

Drug delivery system of dual-responsive PF127 hydrogel with polysaccharide-based nano-conjugate for textile-based transdermal therapy.

Pluronic F-127 based dual-responsive (pH/temperature) hydrogel drug delivery system was developed involving polysaccharide-based nano-conjugate of hyaluronic acid and chitosan oligosaccharide lactate and applied for loading of gallic acid which is the principal component of traditional Chinese medicine Cortex Moutan recommended in the treatment of atopic dermatitis. The polysaccharide-based nano-conjugate was used as pH-responsive compound in the formulation and its amphiphilic character was determined colorimetrically. Microstructure analysis by SEM and TEM indicated highly porous hydrogel network and well-dispersed micellar structures, respectively, after modification with the nano-conjugate, and so, release property of the hydrogel for drug was significantly improved. Different pH-conditions were applied here to see pH-responsiveness of the formulation and increase in acidity of external environment gradually diminished mechanical stability of the hydrogel and that was reflected on the drug release property. Rheology was performed to observe sol-gel transition of the formulation and showed better rheological properties after modification with nano-conjugate. In this study, the cytotoxicity results of PF127 based formulations loaded with/without gallic acid showed cell viability of > 80.0 % for human HaCaT keratinocytes in the concentration range of 0.0-20.0 µg/ml.

Subchronic (13-week) oral toxicity study in rats with fungal chitin-glucan from Aspergillus niger.

Chitin-glucan is an insoluble biopolymer, composed of chitin and beta-(1,3)-D-glucan, that is a component of the fungal cell wall. This study was conducted to assess the safety of chitin-glucan from the mycelium of Aspergillus niger (Artinia brand) for use as dietary supplement and food ingredient. Chitin-glucan was fed to Wistar rats (20/sex/group) at dietary levels of 0, 1, 5 and 10% for 13 weeks. Clinical and neurobehavioural observations, growth, feed and water consumption, ophthalmoscopy, haematology, clinical chemistry, urinalysis, organ weights, necropsy and histopathological examination revealed no adverse effects of chitin-glucan. Rats fed chitin-glucan at 10% consumed more feed than controls, probably due to lower energy density of their diet. Water intake was increased slightly at all dose levels. These changes were not toxicologically significant. Full and empty caecum weights were increased in mid-dose males and high-dose males and females. This caecal enlargement was a physiological response to the consumption of a high amount of poorly digestible carbohydrate and considered of no toxicological concern. In conclusion, feeding chitin-glucan at dietary levels up to 10% for 13 weeks was tolerated without any signs of toxicity. This level corresponded to 6.6 and 7.0 g chitin-glucan/kg body weight/day in male and female rats, respectively.

Polymeric N-acetyl-D-glucosamine (chitin) induces histionic activation in dogs.

Analyses on the effects of polymeric N-acetyl-D-glucosamine (chitin), which was obtained from squid pen, on histiogenic activation in dogs were carried out with subcutaneous implants (5 x 5 cm2) of polyester non-woven fabric (NWF) supplemented with chitin (chitin group) and NWF (control group). These materials were implanted at 4 sites, on the lumbodorsal and lumbosacral subcutaneous tissues on both sides of the midline in each dog under general anesthesia. The implants and their surrounding tissues were isolated on post-implantation days (PIDs) 2, 4, 8, and 18 under general anesthesia. In the chitin group, the implant was organized gradually and its organization was completed on PID 18, when obvious angiogenesis toward the NWF was observed. On the other hand, in the control group, obvious angiogenesis toward the NWF was not observed macroscopically. Numbers of mononuclear (MN) and polymorphonuclear (PMN) cells concentrated around the implants on PID 2 were larger in the chitin than control group. In the chitin group, formation of granulating tissue around the implant was indicated on PID 4, whereas such a phenomenon was not observed in the control group. From these results, chitin accelerates the migration of MN and PMN cells to the NWF site with rapid follow-up organization of the NWF accompanied by angiogenesis.