Green and alternative strategies for the preparation of silver nanoparticles (AgNP) are the focus of considerable attention, given their wide range of applications. A clean, eco-friendly, low-cost, scalable and straightforward protocol for the production of AgNP is reported, using hydrolyzed spent coffee grounds (HSCG) both as a reducing agent and a stabilizing matrix. The sample was easily recovered in 50–60% yield by centrifugation and lyophilization. Size and morphological analyses combined with X-ray diffraction analysis indicated ca. 6% w/w incorporation of AgNP of about 20 nm size into the HSCG matrix. AgNP-HSCG exhibited efficient antioxidant properties in several chemical assays and antimicrobial activities (MIC< 0.1 mg/mL) against Gram-negative bacteria such as E. coli and P. aeruginosa. Antibacterial devices made of chitosan films containing AgNP-HSCG were also prepared that showed significant inhibition zones against the same bacterial strains, even at the lowest loading (0.3% w/w) of AgNP, and remarkable antioxidant properties in aqueous media. An economic evaluation of the whole process was carried out, demonstrating that manufacturing of both HSCG and chitosan-based antibacterial devices is a convenient and easy-to-perform process, with the potential of full industrial scalability. Overall, the adopted circular approach, designed to reuse a cheap and abundant agri-food waste while avoiding the use of toxic or noxious chemicals, makes HSCG a practical and easily accessible multifunctional material for the clean and sustainable synthesis of AgNP with adequate size and stability for incorporation in efficient antioxidants and antimicrobial devices.
|Titolo:||Silver nanoparticles on hydrolyzed spent coffee grounds (HSCG) for green antibacterial devices|
|Data di pubblicazione:||2020|
|Appare nelle tipologie:||1.1 Articolo in rivista|