Microwave Assisted Preparation of Antimicrobial Chitosan with Guanidine Oligomers and Its Application in Hygiene Paper Products

Abstract

Guanidinylated chitosan (GCS) was prepared by grafting guanidine oligomers onto chitosan under microwave irradiation. The structure of GCS characterized by FT-IR and 1 H NMR verified the covalent bonding between the guanidine oligomers and chitosan; the effects of molar ratio, reaction temperature, and time were investigated and the degree of substitution of GCS reached a maximum of 25.5% under optimized conditions in this work. The resulting GCS showed significantly enhanced antimicrobial activities. The results obtained from the dynamic UV absorption of Escherichia coli (E. coli) and atomic force microscopy (AFM) revealed that the deactivation of E. coli by GCS was due to the destructing of the cell membrane and the prompt release of cytoplasm from the bacterial cells. The adsorption of GCS onto cellulose fibers and the antimicrobial efficiency of the hygiene papers with GCS were also investigated. Microwave irradiation as a green assisted method was applied to promote this reaction. This facile approach allowed chitosan to be guanidinylated without tedious preparation procedures and thus broadened its application as a biocompatible antimicrobial agent.

Chitosan: A Natural Biopolymer with a Wide and Varied Range of Applications

“…In the same way, other authors reported that the guanidinylation of chitosan also has an excellent antibacterial activity although the grafting reaction between guanidine and chitosan requires high temperature [ 57 , 58 ]. More recently, other authors established that the microwave assisted preparation of antimicrobial chitosan with guanidine oligomers diminishes the temperature of the grafting reaction [ 59 ]. The obtained composite also showed a significant increases of the antimicrobial activity in comparison to the raw chitosan [ 59 ].…”

“…More recently, other authors established that the microwave assisted preparation of antimicrobial chitosan with guanidine oligomers diminishes the temperature of the grafting reaction [ 59 ]. The obtained composite also showed a significant increases of the antimicrobial activity in comparison to the raw chitosan [ 59 ]. In the same way, the guanidinylation reaction of chitosan with dicyandiamide to form chitosan biguanidine hydrochloride has also reported excellent antibacterial and antifungal applications [ 60 ].…”

60Co γ-ray Irradiation Crosslinking of Chitosan/Graphene Oxide Composite Film: Swelling, Thermal Stability, Mechanical, and Antibacterial Properties

“…CS is composed of N-acetyl-D-glucosamine and D-glucosamine unit [ 9 ]. It contains two kinds of functional groups such as hydroxyl and amino groups that endow various properties to composite materials such as biocompatibility, biodegradability, and antibacterial activity [ 10 ]. It is worth noting that CS possesses an excellent film-forming ability, and it can easily be casted into films after dissolution under slightly acidic aqueous conditions.…”

Starch-Based Flexible Coating for Food Packaging Paper with Exceptional Hydrophobicity and Antimicrobial Activity

“…This can be clearly seen from the pictures: the solution of control (or blank) sample became turbid, while the solution of treated samples was still very clear. The results of the growth inhibition of guanidine-based starch had been studied in our previous studies [26,27,28,29,30]. Figure 9c presents the antimicrobial pictures, and the antimicrobial rates were calculated.…”

“…It is a promising form of active packaging and beneficial for both consumers and hygiene industries. Therefore, eco-friendly materials with antimicrobial capacity are in great demand in accordance with the environmental concerns [24,25,26,27,28,29,30]. As such, it is necessary to create a flexible coating for the packaging papers with excellent antimicrobial capacities.…”