Chitosan and silver nanoparticles as pudding with raisins with antimicrobial properties

Chitosan nanoparticles (CS-NP) containing small silver nanoparticles are reported (Ag@CS-NP). CS-NP was synthesized using tripolyphosphate (TPP) as a polyanionic template. TPP also served to electrostatically attract Ag+ inside CS-NP, where it was reduced by the terminal glucosamine units of the biopolymer. This procedure is environmental friendly, inexpensive, and permits the synthesis of very small AgNP (0.93–1.7 nm), with only a discrete dependence from the amount of silver nitrate used (5–200 mg). The obtained hybrid nanocomposites Ag@CS-NP were characterized by DLS, HRTEM, and HAADF–STEM presenting a mean hydrodynamic diameter of 78 nm. The antimicrobial activity of Ag@CS-NP against Candida glabrata, Sacharomyces cerevisiae, Escherichia coli, Klebsiella pneumoniae, Salmonella, Staphylococcus aureus, and Bacillus cereus corresponded to MIC values lower than for AgNO3.

Graphical abstractChitosan nanoparticles (78 nm) containing small silver nanoparticles (0.93–1.7 nm) as a pudding with raisins with interesting antimicrobial activity are reported.Figure optionsDownload full-size imageDownload high-quality image (92 K)Download as PowerPoint slideHighlights► Silver nanoparticles included in chitosan nanoparticles. ► Green way to obtain AgNP. ► Relatively small size of CS-NP (78 nm). ► Very small AgNP (<2 nm).