Development of biopolymer nanocomposite for silver nanoparticles and Ciprofloxacin controlled release.

Screening of biopolymeric gel beads containing Silver NanoParticles (Ag-NPs) stabilized in Guar Gum Alkyl Amine (GGAA) and Ciprofloxacin (Cip) was carried out in order to obtain a novel nanocomposite with controlled release profile of both antimicrobians. The selected matrix composed of Alginate/High Methoxyl Pectin (HMP)/GGAA (4:4:1) was able to co-incorporate Ag-NPs and Cip with encapsulation efficiency higher than 70%. SEM images revealed good cohesivity and compatibility between the biopolymers and the cargos. Beads provided protection against Ag-NPs degradation at acidic pHs and HMP would played a key role providing hydrophobic regions. While Cip release profile showed a pH independent diffusional process, Ag-NPs release was restricted to matrix erodability. Calcium quelating agents and/or alginate degrading enzymes could modulate the release profile. The bactericidal activity of beads was tested in liquid medium, showing cooperative effects between the antimicrobials against Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus and Staphylococcus aureus. TEM images confirmed interaction of Ag-NPs with bacterial surfaces followed by membrane damage. Results suggested the nanocomposite matrix as a promising system for oral treatment of intestinal infectious diseases caused by multidrug resistant and unknown microorganisms, since both Cip and Ag-NPs would be able to reach intestine in the active form.