Preparation, Characterization, and Cytotoxicity Evaluation of Zinc Oxide–Bacterial Cellulose–Chitosan Hydrogels for Antibacterial Dressing

Abstract

Lin et al. evaluated the cell compatibility and antibacterial activity of bacterial cellulose-chitosan (BC-CS) membranes in vitro. [6] BC is widely used in antibacterial aspects. Wu et al. proposed a preparation method of slow-released antimicrobial wound dressing. [7] Common antibacterial agents for improving BC include benzalkonium chloride, [8] copper, silver, ZnO nanoparticles, sulfadiazine silver, [9] polyhexamethylene guanidine hydrochloride (PHMB), [10] sericin, CS, propolis, [11] and so on. Recently, some researchers were interested in sericin. Napavichayanun et al. [12] combined sericin with PHMB to develop a dressing that was beneficial to the wound. The modified cotton fabric prepared by Doakhan et al. using sericin and nano-TiO 2 had well antibacterial activity and durability. [13] Maneerung et al. used a chemical reduction method to prepare BC antibacterial wound dressings containing silver nanoparticles. [14] CS was obtained by deacetylation of chitin, which was the most abundant naturally occurring biopolymer after cellulose. [15] CS is considered to be a promising biomedical material because of its good biocompatibility, rich functional groups, nontoxicity, degradability, and antibacterial properties. Although CS and BC had such significant advantages, related studies had shown that they were rarely used alone. The reason was that the hydrogels formed by CS had low mechanical strength [16] such as poor flexibility and low ability to elongate and the BC hydrogels itself did not have antibacterial properties. [17,18] CS could be combined with other biopolymers to improve properties. Wu et al. [19] enhanced the mechanical strength of CS by adding oxidized chitin nanocrystals to the CS film. To the best of our knowledge, zinc oxide had not been reported in CS and BC composite hydrogels. Some studies only considered a single factor, which leaded to some inevitable defects. For example, the composite hydrogels were formed by using BC and CS, but the antibacterial property was low due to partial reaction of the amino group on the CS. For example, Liang et al. found that the antimicrobial efficiency of composite films against Escherichia coli was reduced. [20] On the other hand, excessive zinc oxide can cause severe cytotoxicity. Vandebriel et al. suggested that zinc oxide nanoparticles may be cytotoxic In this work, a kind of novel antibacterial and biocompatible composite hydrogels composed of zinc oxide, bacterial cellulose (BC), and chitosan (CS) are prepared via immersing the oxidized BC hydrogels in CS solution and then combining zinc oxide in alkaline environment. The structure and properties of the composite hydrogels are characterized by different techniques. The results of Fourier transform infrared spectroscopy and X-ray diffraction prove the successful preparation of composite hydrogels. Scanning electron microscopy is used to study the microscopic morphology of hydrogels. The results show that the zinc oxide particles are successfully attached to the bacterial cellulose. From the results of t...

Fabrication of Paper Sheets Coatings Based on Chitosan/Bacterial Nanocellulose/ZnO with Enhanced Antibacterial and Mechanical Properties

“…Therefore, two antimicrobial factors were chosen to fabricate the paper coating to obtain the additive effect. Other published papers employ the same strategy, i.e., the use of two antimicrobial agents [ 23 , 36 ]. The assay of antimicrobial activity of the composites revealed that the combination of chitosan and ZnO was more effective than chitosan alone and led to a 100% reduction in bacterial titer, while paper coated with pristine chitosan exhibited a 96.36% reduction.…”

“…To our knowledge, only one research article covered the use of chitosan, bacterial cellulose, and ZnO [ 23 ]. However, the application and processing of the components differed from the method applied in this paper.…”

Cellulose–Chitosan Functional Biocomposites

“…Therefore, there are many other approaches which use combinations of different formulations together with chitosan to improve its antimicrobial effects. Specifically, for wound dressings, many different formulations and approaches have been applied to improve their antibacterial activity, such as: silver formulations [ 138 , 139 ], zinc oxide [ 140 ], nitric oxide [ 104 ], ferulic acid [ 141 ], etc. Through carboxymethylation and selective oxidation of bacterial cellulose and cross-linking with chitosan, Xie et al produced a cellulose–chitosan wound dressing that inhibited bacterial proliferation and exhibited an 80% wound-healing rate after three weeks.…”

Antibacterial hydrogel dressings and their applications in wound treatment

“…Most of the studies in the literature were performed using silver nanoparticles, however, also some different nanoparticles can be found, namely copper (Ponco and Helmiyati, 2020), gold (Mahmoud et al, 2019), zinc oxide (Kai and Xuesong, 2020) silver-titanium dioxide nanoparticles as an antibacterial agent. The kinetics of drug release was performed by using various mathematical models, where the Higuchi model was found to be the best fit.…”