Self-antibacterial chitosan/Aloe barbadensis Miller hydrogels releasing nitrite for biomedical applications

Because of the toxic glutaraldehyde, the chitosan-glutaraldehyde hydrogels are seriously limited in biomedical applications. In this study, exploiting bioactive compounds of Aloe barbadensis Miller, the chitosan/Aloe barbadensis Miller-glutaraldehyde (CS/AV-GDA) hydrogels were fabricated with 4-fold lower glutaraldehyde concentration without compromising hydrogel characteristics. The gelation time was controlled from a few seconds to several hours. The elastic modulus was varied from 483 to 99940 Pa. The CS/AV-GDA hydrogels could release the natural nitrite amount from 24.0 to 89.6 mu M within the first hour for antibacterial activity, then continuously deliver a few mu M every next hour for cell activities. The antibacterial test against Escherichia coli and Staphylococcus aureus revealed that the CS/AV-GDA hydrogels could kill the planktonic bacteria 5-fold more highly than control and prevent bacteria attachment on hydrogel surface effectively. Although the CS/AV-GDA hydrogels consumed only 0.25% glutaraldehyde concentration, their antibacterial capacities were comparable to chitosan-only hydrogels with 2% glutaraldehyde. For cytotoxicity tests, the CS/AV-GDA hydrogels using 0.25% glutaraldehyde concentration induce the human dermal fibroblasts proliferation significantly. All CS/AV-GDA hydrogels with glutaraldehyde crosslinker less than 1% showed non-cytotoxicity. As a result, the new CS/AV-GDA hydrogels might become an attractive candidate for medicine regeneration and tissue engineering. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

In this study, bioactive CS/AV-GDA hydrogels were fabricated with reduced glutaraldehyde concentration using compounds of Aloe barbadensis Miller, showing excellent antibacterial activity against Escherichia coli and Staphylococcus aureus. The hydrogels released natural nitrite and promoted cell activities, demonstrating potential for biomedical applications in medicine regeneration and tissue engineering.