Quaternized Carboxymethyl Chitosan-Based Silver Nanoparticles Hybrid: Microwave-Assisted Synthesis, Characterization and Antibacterial Activity

Abstract

A facile, efficient, and eco-friendly approach for the preparation of uniform silver nanoparticles (Ag NPs) was developed. The synthesis was conducted in an aqueous medium exposed to microwave irradiation for 8 min, using laboratory-prepared, water-soluble quaternized carboxymethyl chitosan (QCMC) as a chemical reducer and stabilizer and silver nitrate as the silver source. The structure of the prepared QCMC was characterized using Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (NMR). The formation, size distribution, and dispersion of the Ag NPs in the QCMC matrix were determined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM) analysis, and the thermal stability and antibacterial properties of the synthesized QCMC-based Ag NPs composite (QCMC-Ag) were also explored. The results revealed that (1) QCMC was successfully prepared by grafting quaternary ammonium groups onto carboxymethyl chitosan (CMC) chains under microwave irradiation in water for 90 min and this substitution appeared to have occurred at -NH2 sites on C2 position of the pyranoid ring; (2) uniform and stable spherical Ag NPs could be synthesized when QCMC was used as the reducing and stabilizing agent; (3) Ag NPs were well dispersed in the QCMC matrix with a narrow size distribiution in the range of 17–31 nm without aggregation; and (4) due to the presence of Ag NPs, the thermal stability and antibacterial activity of QCMC-Ag were dramatically improved relative to QCMC.

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

“…Compared to pure CMC, the obvious diffraction peaks at 2θ=38.03°, 44.14°, 64.47°, 77.26°, and 81.35° in the CMC-Ag hybrids (Figure 2 [a-c]) corresponded to the (111), (200), (220), (311), and (222) planes of silver crystals with a face centered cubic lattice structure (JCPDS 04-0783), which is consistent with our previous research. 29 These results indicate that Ag + was reduced to Ag 0 and pure well-crystallized metallic silver was formed in all three synthetic protocols. According to the literature, 35 the decreasing characteristic peak intensity of silver in the XRD patterns indicates that the amount of silver in hybrids decreased.…”

“…Antimicrobial tests was performed based on our previous report. 28,29 First, S. aureus and E. coli were separately adjusted by addition of sterile distilled water to obtain 10 7 CFU/mL solutions. Next, antimicrobial solutions were diluted in phosphate buffer (pH 7.2) to appropriate concentrations, and 10 mL of each sample was added to sterile petri dishes containing 10 mL of nutrient agar solution.…”

Quaternary Ammonium Chitosans: The Importance of the Positive Fixed Charge of the Drug Delivery Systems

“…Concerning the use of QCMC as antimicrobial and antibacterial agents Yin et al [49], prepared blend films based on QCMC and PVA loaded with Cu 2+ , as potential biomaterials for biomedical application, with good antibacterial activity, in fact, they inactivated 98.3% of S. aureus and 99.9% of E. coli. For the same application, Huang et al [50], synthesized silver nanoparticles in an aqueous solution of QCMC, used as a chemical reducing and stabilizing agent. These nanoparticles had a better antibacterial property and a lower toxicity than a solution of QCMC.…”

The dual anti‐caries effect of carboxymethyl chitosan nanogel loaded with chimeric lysin ClyR and amorphous calcium phosphate

“…Because the properties of CMC increase the exposure time of drugs in the oral environments, provide sustained drug release, and minimize the degradation of drugs, this substance is a candidate vehicle [22,23]. Examples of CMC loaded with various drugs include CMC-Ag, CMC-ornidazole, and CMC-ßcyclodextrin [24][25][26].…”