Silver nanoparticles (AgNPs) receive increase interest in application for many fields (1) due to their efficiency in antibacterial (2), antifungal (3), antiviral (4), anticancer (5), and antioxidant activities (6). Synthesis of AgNPs can be generally performed by reacting silver salts with certain reducing agents from natural such as plant extracts (7) or chemically synthesized agents (8). The reducing agents from natural resources have gain increasing interest since there are less hazardous waste than those from chemical synthesis. Polysaccharides are one of the natural interesting groups that some of them, e.g. starch, dextran, and cellulose were used as a reducing agent for synthesis of metal nanoparticles. For example, our group previously reported the use of starch derivatives from rice for synthesis of AgNPs (9). Bankura et al. reported the use of dextran to synthesize gold nanoparticles (10). For cellulose, there are some reports on using cellulose derivatives such as methylcellulose and carboxymethyl cellulose to synthesize AgNPs (11-13). However, there is still less report on factors affecting the obtained AgNPs synthesized by using cellulose derivatives as a reducing agent as well as the comparison of reducing efficiency among many types of cellulose derivatives.Cellulose is an organic polysaccharide consisting
SummaryThe aim of this study was to synthesize silver nanoparticles (AgNPs) by using cellulose derivatives as a reducing agent. Methyl cellulose (MC), hydroxy ethylcellulose (HEC), and hydroxypropyl methylcellulose (HPMC) were compared for their reducing property. HPMC presented the highest reducing power, with equilibrium concentration (EC) of 84.6 ± 4.5 µmol Fe 2+ /g, followed by MC and HEC, with the EC of 62.3 ± 1.4, and 38.1 ± 3.2 µmol Fe 2+ /g, respectively. Using these cellulose derivatives as a reducing agent and silver nitrate as a precursor in fabrication of silver nanoparticles (AgNPs), three cellulose-AgNPs, HEC-AgNPs, MC-AgNPs, and HPMC-AgNPs, were obtained. The cellulose-AgNPs showed different maximum absorptions confirming AgNPs spectra at 415, 425, and 418 nm, respectively. Reaction parameters such as pH, temperature, and period of reaction affected intensity of the maximum absorptions and size of AgNPs. Using 0.3% cellulose solution at pH 9 and reaction at 70°C for 90 min, the particle size of MC-AgNPs, HEC-AgNPs, and HPMC-AgNPs was 97.7 ± 2.4, 165.6 ± 10.6, and 51.8 ± 1.6 nm, respectively. AgNPs obtained from different cellulose derivatives and various preparation parameters possess different inhibition potential against Escherichia coli and Staphylococcus aureus. The cellulose-AgNPs have higher effective against E. coli than S. aureus. HPMC-AgNPs showed significantly higher antibacterial activity than MC-AgNPs and HEC-AgNPs, respectively.These results suggest that the type of cellulose derivatives and the reaction parameters of the synthesis such as pH, temperature, and reaction period play an important role to the yield and physicochemical property of the obtained AgNPs.