In situ green synthesis of antimicrobial carboxymethyl chitosan–nanosilver hybrids with controlled silver release

Abstract

In order to fabricate antimicrobial carboxymethyl chitosan–nanosilver (CMC-Ag) hybrids with controlled silver release, this study demonstrated comparable formation via three synthetic protocols: 1) carboxymethyl chitosan (CMC) and glucose (adding glucose after AgNO 3 ), 2) CMC and glucose (adding glucose before AgNO 3 ), and 3) CMC only. Under principles of green chemistry, the synthesis was conducted in an aqueous medium exposed to microwave irradiation for 10 minutes with nontoxic chemicals. The structure and formation mechanisms of the three CMC-Ag hybrids were explored using X-ray diffraction, ultraviolet-visible spectroscopy, transmission electron microscopy, and Fourier-transform infrared analyses. Additionally, antimicrobial activity and in vitro silver release of the three synthesized hybrids were investigated in detail. The results revealed that a large number of stable, uniform, and small silver nanoparticles (AgNPs) were synthesized in situ on CMC chains via protocol 1. AgNPs were well dispersed with narrow size distribution in the range of 6–20 nm, with mean diameter only 12.22±2.57 nm. The addition of glucose resulted in greater AgNP synthesis. The order of addition of glucose and AgNO 3 significantly affected particle size and size distribution of AgNPs. Compared to CMC alone and commercially available AgNPs, the antimicrobial activities of three hybrids were significantly improved. Of the three hybrids, CMC-Ag1 synthesized via protocol 1 exhibited better antimicrobial activity than CMC-Ag2 and CMC-Ag3, and showed more effective inhibition of Staphylococcus aureus than Escherichia coli . Due to strong coordination and electrostatic interactions between CMC and silver and good steric protection provided by CMC, CMC-Ag1 displayed stable and continuous silver release and better performance in retaining silver for prolonged periods than CMC-Ag2 and CMC-Ag3.

Zero Valent Iron Nanoparticle-Loaded Nanobentonite Intercalated Carboxymethyl Chitosan for Efficient Removal of Both Anionic and Cationic Dyes

“…Additionally, the peak at 1329 cm –1 is ascribed to C–OH stretching vibration . The two peaks at 1420 and 1602 cm –1 are assigned to symmetric and asymmetric stretching vibrations of −COOH, respectively . Moreover, the peak at 2932 cm –1 is attributed to C–H stretching and the peak at 3447 cm –1 is assigned to the overlapping of N–H and O–H stretching vibrations.…”

“…Also, the nZVI@nBent–CMC composite pattern shows this distinctive peak of nZVI without the appearance any peaks for other iron oxides, which could be attributed to the complete coverage of nZVI with nBent–CMC that protects its surface from oxidation . Furthermore, nBent was recognized by the appearance of the distinguishing peaks at 2θ = 35 and 61.8°, whereas CMC was identified by the occurrence of a characteristic peak at 2θ = 21.1° . Thus, XRD patterns show the main components quite evidently, which confirms that the nZVI@nBent–CMC composite has been successfully synthesized.…”

Antimicrobial Activity of Composite Consisting of Cellulose Nanofibers and Silver Nanoparticles

“…The analysis of the IR data of the composites suggest that Ag NPs and CNF/PVA form stable composite via electrostatic interaction between negatively charged carboxylic groups and positively charged groups on the Ag NPs. Similar results were observed previously in other inorganic nanomaterials and cellulose composites …”

Green Synthesized Chitosan/Chitosan Nanoforms/Nanocomposites for Drug Delivery Applications

“…In vitro release experiments showed that CA/SA/Ch NPs had the function of sustained release, indicating that SA/Ch NPs can be used as a promising carrier for CA [ 142 ]. Antimicrobial carboxymethyl chitosan-nanosilver (CMC-Ag) hybrids with controlled silver release was fabricated by Huang et al [ 143 ]. Under principles of green chemistry, the synthesis was conducted in an aqueous medium exposed to microwave irradiation for 10 min with non-toxic chemicals.…”