Synthesis Of AgNPs With Eriobotrya Japonica Leaf/Seed Extract And Their Application On Chitosan Nonwoven

Chitosan nonwoven possesses a lot of good properties, such as good moisture absorption and water retention ability, fine bioactivity, biocompatibility and biodegradability and moderate antibacterial activity. Therefore, it has been widely applied as a wound dressing in medicine and hygiene field. Although chitosan nonwoven bears antibacterial activity, its antibacterial efficiency is not satisfactory and still needs to be improved. Silver nanoparticle(AgNP) has already been demonstrated a highly effective inhibitory and bacteridal agent and has a broad spectrum antibacterial activity.Biosynthesis of AgNPs by plant extracts is of environmental protection, rapidness and high-efficiency, security and non-toxicity. For this reason, in the present paper, the plant meditated AgNPs were incorporated into chitosan nonwoven to further enhance its antibacterial property.In this paper, AgNPs were bio-reduced from silver nitrate using Eriobotrya japonica(E. japonica) leaf and seed extract. And the biosynthesized AgNPs were loaded on chitosan nonwoven via impregnation and in-situ method. The biosynthesis condition of AgNPs was investigated. The prepared AgNPs were subjected to a sequence of characterizations and measurements. The colormetric data and silver content of silver-containing chitosan nonwoven were recored as a function of reactants concentration and washing cycles. The influence of addition of AgNPs on the structure and property of chitosan fiber was discussed. The antibacterial activity and lundering durability of AgNPs treated chitosan nonwoven were determined. The main conclusions are as follows:(1) Both E. japonica leaf and seed extract possess the ability to reduce silver nitrateinto silver nanoparticles under proper conditions. The higher the temperature, the smaller the particle size of E. japonica leaf AgNPs. And the more the E. japonica seed extract dosage, the smaller the particle size of E. japonica seed AgNPs. Both E. japonica leaf and seed AgNPs were near-spherical in shape with the average particle size of 19 nm and23 nm and exhibited excellent antibacterial activity against Escherichia coli(E. coli) and Staphylococcus aureus(S. sureus).(2) The chitosan nonwoven turned yellow after treated with E. japonica leaf AgNPs.The color deepened with increase in the silver content of the nonwoven. A fraction of AgNPs were chemically combined with chitosan fiber macromolecule chain. The incorporation of AgNPs had no impact on the thermal stability and crystalline structure of chitosan fiber. Silver-containg chitosan nonwoven showed excellent antibacterial activity and lundering durability against E. coli.(3) The E. japonica leaf extract adsorbed by the nonwoven enables to reduce the Ag+adsorbed into AgNPs under steam heating. The silver content of the nonwoven increased with increasing the extract dosage. Correspondingly, the antibacterial efficiency of the obtained nonwoven against S. aureus enhanced. The AgNPs treated chitosan nonwoven through in-situ method exhibited excellent lundering durability.(4) The pH value of E. japonica seed AgNPs has great effect on the silver concent of the chitosan nonwoven. The lower the pH value, the higher the silver content of the nonwoven. When the immersion time is 30 min, the temperature is 60 oC and the pH value of AgNPs solution is close to neutral, the silver content of the obtained chitosan nonwoven is 3566.34 mg/Kg and the bacterial reduction for S. aureus reached 99.88%.Even after 20 washings, the bacterial reduction is still over 98%.