Silver nanoparticles fabricated by reducing property of cellulose derivatives

The 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 Fe²⁺/g, followed by MC and HEC, with the EC of 62.3 ± 1.4, and 38.1 ± 3.2 µmol Fe²⁺/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.