Effect of recombinant human epidermal growth factor impregnated chitosan film on hemostasis and healing of blood vessels

Chitosan-microencapsulated rhEGF in promoting wound healing

AIMS

Chitosan and epidermal growth factor (EGF) have been shown to improve wound healing. This study investigates the healing effects of a spray solution (NewEpi, JoyCom Bio-Chem Co. Ltd., Taiwan) containing recombinant human EGF (rhEGF) delivered via a newly patented technology-chitosan microencapsulated nanoparticles.

METHODS

On Wistar rats, two full-thickness wounds on the dorsum bilateral of the spine were created. The rats were randomised to the following treatment groups: hydrogel, wet dressing, foam, rhEGF spray and rhEGF spray+foam. Sterile dressings were applied and changed daily. A total of 2μg of rhEGF was administered in two sprays during each dressing change. All animals were euthanised on day 14. Tissue samples were taken from the wound bed, including an area of 2cm surrounding the wound margin for histological evaluations.

RESULTS

Wounds treated with the rhEGF spray achieved the greatest size reduction by day 14 compared with other types of conventional dressings. An overall significant difference in levels of collagen synthesis existed between groups (p<0.01). Pair-wise comparisons showed that the rhEGF spray treatment significantly promoted higher levels of mature Type I collagen than any other conventional dressings (p<0.01), whereas non-rhEGF treatments resulted in higher levels of Type III collagen. The regenerated tissue in rhEGF spray treatment groups was also in alignment with that of normal skin. Epidermis, dermis and hair follicles were easily observed in wounds treated with the rhEGF spray.

CONCLUSION

The major challenge of topical application of rhEGF was overcome by using a new drug delivery technology: chitosan-rhEGF nanoparticles. The positive healing effects observed in this study suggest the therapeutic potentials of this novel rhEGF topical spray solution.

Enhanced Healing and Antimicrobial Efficacy of Chitosan-g-Polyacrylamide in a Rat Model of Gingival Ulcers

Patients in dental hospitals often experience oral ulcerative lesions, which lead to pain and affect the patient's quality of life. At present, the goal of treating oral ulcerative lesions with drugs is to reduce inflammation and promote ulcer healing. However, very few antibacterial and hemostatic drugs are designed to be suitable for the microenvironment of gingival ulcers. Based on this, we have designed a natural therapeutic agent for oral ulcerative lesions that meets the various requirements of oral ulcerative lesion medication. The chitosan-g-polyacrylamide (CP) copolymer is composed of chitosan as the main chain and polyacrylamide polymers as the side chains. Antibacterial experiments show that this polymer can effectively inhibit the proliferation of Gram-negative (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). In vitro cell experiments also show that the CP copolymer is non-toxic, which is conducive to ulcer wound healing. Coagulation experiments prove that the CP copolymer can accelerate blood coagulation to stop bleeding. In experiments using a Wistar rat gingival ulcer model, the CP copolymer significantly promoted ulcer healing and shortened the healing time. These results indicate that the CP copolymer may serve as a potential therapeutic agent for oral ulcerative lesions.

Multifunctional Ag@MOF-5@chitosan non-woven cloth composites for sulfur mustard decontamination and hemostasis

Attachment of MOF-5 particles on the surface of carboxymethylated non-woven chitosan cloth (denoted MOF-5@chitosan) was achieved by a layer-by-layer technique in an alternating bath of Zn(OAc)2·2H2O and terephthalic acid solutions. Afterwards, silver nanoparticles were formed/loaded within the resulting MOF-5@chitosan by irradiating at 350 nm wavelength the composite immersed in an aqueous solution of silver nitrate of different concentrations, leading to the formation of ternary composites (denoted Ag@MOF-5@chitosan) which were thoroughly characterized by various techniques. Decontamination of HD over the composites was systematically studied and the results showed that decontamination efficacy increased with the increase of silver amount. The decontamination rate constant and half-life of HD were found to be 0.011 min-1 and 63.0 min over the optimal composite, respectively. Remarkably, attachment of the silver nanoparticles and MOF-5 on the chitosan cloth surface did not interfere with chitosan's original hemostatic capability that was confirmed through the arterial hemostasis of rats. It is expected that the multifunctional composite material can find practical applications in the fields of hemostasis, sterilization and chemical war agent decontamination.

Chitosan-Based Multifunctional Platforms for Local Delivery of Therapeutics

Chitosan has been widely used as a key biomaterial for the development of drug delivery systems intended to be administered via oral and parenteral routes. In particular, chitosan-based microparticles are the most frequently employed delivery system, along with specialized systems such as hydrogels, nanoparticles and thin films. Based on the progress made in chitosan-based drug delivery systems, the usefulness of chitosan has further expanded to anti-cancer chemoembolization, tissue engineering, and stem cell research. For instance, chitosan has been used to develop embolic materials designed to efficiently occlude the blood vessels by which the oxygen and nutrients are supplied. Indeed, it has been reported to be a promising embolic material. For better anti-cancer effect, embolic materials that can locally release anti-cancer drugs were proposed. In addition, a complex of radioactive materials and chitosan to be locally injected into the liver has been investigated as an efficient therapeutic tool for hepatocellular carcinoma. In line with this, a number of attempts have been explored to use chitosan-based carriers for the delivery of various agents, especially to the site of interest. Thus, in this work, studies where chitosan-based drug delivery systems have successfully been used for local delivery will be presented along with future perspectives.

Layer-by-layer assembly of Cu3(BTC)2 on chitosan non-woven fabrics: a promising haemostatic decontaminant composite material against sulfur mustard

Anchoring Cu₃(BTC)₂ on the surface of chitosan non-woven fabrics results in formation of a new haemostatic decontaminant composite materials.

An investigation of chitosan and its derivatives on red blood cell agglutination

RBC agglutination was determined by the number of protonated amine groups on chitosan and its derivatives.