Biomaterials based on freeze dried surface-deacetylated chitin nanofibers reinforced with sulfobutyl ether β-cyclodextrin gel in wound dressing applications

In vitro and in vivo evaluation of a nanofiber wound dressing loaded with melatonin

Wound healing is a complicated process that takes a long time to complete. The three-layer nanofiber wound dressing containing melatonin is highly expected to show remarkable wound repair by reducing the wound healing time. In this study, chitosan (Cs)-polycaprolactone (PCL)/ polyvinylalcohol (PVA)-melatonin (MEL)/ chitosan-polycaprolactone three-layer nanofiber wound dressing was prepared by electrospinning for melatonin sustained release. The characteristics of the wound dressing were further evaluated. The wound dressing had a high water uptake after 24 h (401%), and the water contact angle results showed that it had hydrophilicity effect that supported the cell attachment. The wound healing effect of wound dressing was examined using a full-thickness excisional model of rat skin by the local administration of MEL. The gene expressions of transforming growth factor-beta (TGF-β1), alpha-smooth muscle actin (α-SMA), collagen type I (COL1A1), and collagen type III (COL3A1) were further studied. The histopathological evaluation showed the complete regeneration of the epithelial layer, remodeling of wounds, collagen synthesis, and reduction in inflammatory cells. The NF + 20% MEL significantly increased TGF-β1, COL1A1, COL3A1, and α-SMA mRNA expressions. This wound dressing may have a considerable potential as a wound dressing to accelerate the wound healing.

Functional Nanofibrous Biomaterials of Tailored Structures for Drug Delivery-A Critical Review

Nanofibrous biomaterials have huge potential for drug delivery, due to their structural features and functions that are similar to the native extracellular matrix (ECM). A wide range of natural and polymeric materials can be employed to produce nanofibrous biomaterials. This review introduces the major natural and synthetic biomaterials for production of nanofibers that are biocompatible and biodegradable. Different technologies and their corresponding advantages and disadvantages for manufacturing nanofibrous biomaterials for drug delivery were also reported. The morphologies and structures of nanofibers can be tailor-designed and processed by carefully selecting suitable biomaterials and fabrication methods, while the functionality of nanofibrous biomaterials can be improved by modifying the surface. The loading and releasing of drug molecules, which play a significant role in the effectiveness of drug delivery, are also surveyed. This review provides insight into the fabrication of functional polymeric nanofibers for drug delivery.

Chitin and Chitinases: Biomedical And Environmental Applications of Chitin and its Derivatives

Disposal of chitin wastes from crustacean shell can cause environmental and health hazards. Chitin is a well known abundant natural polymer extracted after deproteinization and demineralization of the shell wastes of shrimp, crab, lobster, and krill. Extraction of chitin and its derivatives from waste material is one of the alternative ways to turn the waste into useful products. Chitinases are enzymes that degrade chitin. Chitinases contribute to the generation of carbon and nitrogen in the ecosystem. Chitin and chitinolytic enzymes are gaining importance for their biotechnological applications. The presence of surface charge and multiple functional groups make chitin as a beneficial natural polymer. Due to the reactive functional groups chitin can be used for the preparation of a spectrum of chitin derivatives such as chitosan, alkyl chitin, sulfated chitin, dibutyryl chitin and carboxymethyl chitin for specific applications in different areas. The present review is aimed to summarize the efficacy of the chitinases on the chitin and its derivatives and their diverse applications in biomedical and environmental field. Further this review also discusses the synthesis of various chitin derivatives in detail and brings out the importance of chitin and its derivatives in biomedical and environmental applications.

Preparation, Mechanical Properties, and Biocompatibility of Graphene Oxide-Reinforced Chitin Monofilament Absorbable Surgical Sutures

Chitin (CT) is a good material to prepare surgical sutures due to its conspicuous biological characteristics. However, the poor mechanical strength of pure CT sutures limits its application. In order to improve its strength, a composite monofilament absorbable suture was prepared in this study using graphene oxide and chitin (GO-CT) using a green method. FT-IR spectra showed that GO-CT contained the characteristic functional groups of GO and CT, indicating that a GO-CT suture was successfully obtained. With the addition of a small amount of GO (1.6wt% solution) in chitin, the breaking tensile strength, knot strength, and knot-pull strength of the GO-CT suture were significantly improved compared to the CT suture. The biocompatibility of the GO-CT suture in vitro was checked by tetrazolium-based colorimetric assays and no cytotoxicity to L929 cells was found. In vivo, the subcutaneous implantation of GO-CT sutures in the dorsal skin of rats found no abnormalities by hematoxylin-eosin staining. Furthermore, there were no significant changes in the gene expression of the inflammatory mediators, interleukin 1β (IL-1β), tumor necrosis factor-α, IL-6, IL-17A, interferon-γ, or IL-10; however, the expression of transforming growth factor β was significantly increased in the first week. In summary, GO-CT sutures may have potential as a suture material in the clinic.

Preparation, characterization and application of rod-like chitin nanocrystal by using p-toluenesulfonic acid/choline chloride deep eutectic solvent as a hydrolytic media

Chitin nanocrystal (ChiNC) was fabricated based on p-toluenesulfonic acid -choline chloride deep eutectic solvent treatment. The obtained ChiNC was about 12-44 nm in width and 206-399 nm in length. The crystalline structure and the functional groups of ChiNC were maintained during the preparation process. Moreover, porcine pancreas lipase (PPL) was successfully immobilized onto the ChiNC to form the immobilized PPL (PPL@ChiNC). The resulting PPL@ChiNC has enzyme loading and activity recovery of 35.6 mg/g and 82.5%, respectively. The thermal stability, pH and temperature adaptabilities of PPL@ChiNC was improved, comparing with free PPL. The demonstrated DES treatment process was efficient for ChiNC preparation and the as-prepared ChiNC exhibited great potentials in biocatalysis and biomedical field.

Dual controlled release nanomicelle-in-nanofiber system for long-term antibacterial medical dressings

Long-term antibacterial medical dressings can prevent infection as skin wounds heal. In this study, we used the hydrophobic antibacterial drug amoxicillin as a model to prepare drug-loaded nanomicelles using a film dispersion-hydration method, and drug-loaded nanomicelles were coaxially electrospun into nanofiber to create a novel nanomicelle-in-nanofiber (NM-in-NF) drug delivery system. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of nanomicelles and nanofibers. Thermal property of as-prepared samples was tested using differential scanning calorimetry. The drug release behavior, cytotoxicity, and antibacterial properties of NM-in-NFs were examined in vitro to evaluate the system's potential to be used in the treatment of skin wounds. Experimental results indicated that the novel NM-in-NF system had dual controlled release effect, which greatly reduced burst release and prolonged effective drug duration. Moreover, NM-in-NFs was also found to be safe and non-toxic, with a broad-spectrum antibacterial activity. It thus could potentially be used in long-term antibacterial medical dressings to treat skin wounds.

Hair growth-promoting activities of chitosan and surface-deacetylated chitin nanofibers

In this study, the effects of chitosan and surface-deacetylated chitin nanofibrils (SDACNFs) on hair growth were evaluated. In human follicle dermal papilla cells in vitro, chitosan and SDACNFs were shown to increase cell growth on day 3 after the initiation of treatment, together with an increase in the production of fibroblast growth factor-7 (FGF-7) by these cells on day 3. Furthermore, in an in vivo study in mice, chitosan and SDACNF application promoted hair growth. The number of anagen follicles significantly increased compared with that in the control group, whereas the number of telogen follicles significantly decreased in the chitosan and SDACNF groups. In the chitosan and SDACNFs groups, moreover, the expression levels of FGF-7 and Sonic hedgehog were significantly upregulated in hair follicles. Overall, our results demonstrated that chitosan and SDACNFs promoted hair growth and therefore may have applications as novel therapeutic agents for the treatment of hair loss in patients.

Preparation and evaluation of freeze dried surface-deacetylated chitin nanofiber/sacran pellets for use as an extended-release excipient

Pelleted preparations were formulated from sacran (Sac), an anionic, sulfated, carboxyl-containing polysaccharide, which is extracted from the Japanese indigenous cyanobacterium Aphanothece sacrum, and surface-deacetylated chitin nanofibers (SDACNF). The use of this material as an extended-release excipient for tetrahydrocurcumin (THC), a model drug that is used to treat wounds via its radical scavenging ability was examined. The THC used in the study was complexed with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), which increases its water solubility. The radical scavenging activity of the THC/HP-β-CD complex (molar ratio of 1:1) was significantly higher than the values for SDACNF or Sac alone. The rate of release of THC from the Sac/SDACNF pellets containing the THC/HP-β-CD complex decreased with increasing Sac content in the pellet, suggesting that Sac/SDACNF (1:1) and Sac alone pellets function as extended-release excipients for THC. The findings reported here indicate that this can be attributed to the ability of the Sac component to retain fluids, thus extending the effects of the drug. In view of the above experimental outcomes, i.e. wound healing efficacy, fluid absorption, retention and the extended drug release of the system indicates that this preparation, in the appropriate ratios, has the potential for use as a controlled-release drug in wound healing.

Preparation of chitin-amphipathic anion/quaternary ammonium salt ecofriendly dressing and its effect on wound healing in mice

Objective

This study aimed to prepare an eco-friendly dressing using a chitin-derived membrane with amphipathic anion/quaternary ammonium salt designed for antibacterial purposes.

Methods

Four dressings were prepared and group A was chitin, group B was chitin + amphiphilic ion, group C was chitin + quaternary ammonium salt, group D was chitin + amphiphilic ion + quaternary ammonium salt.

Results

In the group D material, precipitation of adherent composite ions was observed. The contact angle test showed that the material was hydrophilic. The drug loading rate in groups B, C, and D was 40-50 (ug:mg), the entrapment efficiency was 70%-75% (P>0.05), and the cumulative release percentages were 87.3%, 88.7%, and 90.2% after 72h for group B, C, and D, respectively. The anti-bacterial activity in vitro was in the order D>C>B>A> control (P>0.05). The anti-pollution activity in vitro was in the order D>B>C>A (P<0.05). The cell proliferation inhibition test showed slight proliferation inhibition (P<0.05) only on the seventh day for group D. Seven days after injury, the wound healing rate was in the order D>C> commercial chitin dressing >B>A> control (P<0.05), and the length of the neonatal epithelium also showed the same trend. Additionally, PCNA and CD31 expression indicated that cell proliferation and angiogenesis were enhanced when skin defects were covered with the D group material (P<0.05).

Conclusion

chitin-amphiphilic ion/quaternary ammonium salt dressing was successfully prepared. The antibacterial and antipollution effects of the prepared material (group D) were both very good, acting to promote wound healing.

Oral Administration of Surface-Deacetylated Chitin Nanofibers and Chitosan Inhibit 5-Fluorouracil-Induced Intestinal Mucositis in Mice

This study investigated the prophylactic effects of orally administered surface-deacetylated chitin nanofibers (SDACNFs) and chitosan against 5-fluorouracil (5-FU)-induced intestinal mucositis, which is a common side effect of 5-FU chemotherapy. SDACNFs and chitosan abolished histological abnormalities associated with intestinal mucositis and suppressed hypoproliferation and apoptosis of intestinal crypt cells. These results indicate that SDACNF and chitosan are useful agents for preventing mucositis induced by anti-cancer drugs.