Assessing Effectiveness of Antimicrobial Cellulosic-Copper Nanoparticles from Appalachian Hardwoods: Red Oak (Quercus rubra) and Yellow Poplar (Liriodendron tulipifera)

Ch. Jiang, G.S. Oporto, M. Hassanzadeh, J. Jaczynski
West Virginia University,
United States

Keywords: nanofibrillated cellulose, copper nanoparticles, appalachian hardwood

Summary:

TEMPO nanofibrillated cellulose (TNFC) from Red oak (Quercus rubra) and Yellow poplar (Liriodendron tulipifera) were used as raw materials to produce a suspension of hybrid cellulose copper nanoparticles. The resulting TNFC-Cu hybrid material was centrifuged and subjected to an alcohol/tert-butanol solvent exchanging stage, followed by a freeze-drying. The hybrid material was tested for antimicrobial properties against a non-pathogenic Escherichia coli DH5α. The bacterial culture for control purposes was diluted 108 times and the one exposed to TNFC-Cu was diluted 106 times. Both bacterial cultures were incubated on Petrifilm plates for 18 hours at 37 ℃. The results showed that TNFC-Cu prepared from Red oak and Yellow poplar resulted in a 5-log and 3-log reduction of the bacterial culture, respectively. Further characterization using energy dispersive x-ray spectroscopy (EDS) indicated that copper weight percentages of TNFC-Cu from Red oak and Yellow poplar were 16.36% and 6.75%, respectively. These results indicate that both TNFC from Red oak and Yellow poplar can be effective templates to stabilize copper for antimicrobial applications, but TNFC-Cu from Red oak showed higher copper weight percentage. Although the concentrations of carboxylate group in both TNFC were similar, about 1.24 mmol/g, the location and availability to reach them on the TNFC may be different.