Recently,
silver, a traditional broad-spectrum
antiseptic, drew increasing attentions as a
solution against
antibiotic resistant bacteria. Various synthetic
polymers and nature
polymers were applied to form
silver polymer composites to cope with the defects (e.g., low hemocompatibility) of
silver-loaded
antimicrobial agents. In this study, an alcohol-soluble
prolamine,
zein, was applied to prepare
silver-
zein composites as novel
antiseptics. Both
zein in
silver (Z]A) and
silver nanoparticles (AgNP) in
zein (A']Z) structures at two pH conditions (i.e., pH = 3.3 and 6.5) were successfully prepared. Several characterization methods (i.e., zeta potential, FTIR, SEM, and turbidity) confirmed the formation of
silver-
zein composites through a
nitrogen-
silver coordination bond and electrostatic interaction. It was found that low pH was critical in facilitating formation and increasing stability of the
silver-
zein composites, probably by inducing electrostatic interaction between
silver and
zein. The
antiseptic activities (i.e., growth inhibition and bactericidal activity) of different
silver-
zein composites were studied against Gram negative E. coli and Gram positive S. aureus . It was revealed that the
silver-
zein composites showed similar or better results against both types of bacteria compared to those of AgNO(3) and AgNP, except for the sample of A']Z-Ac. It had better growth inhibition activity but inferior bactericidal activity than that of AgNP because of its decreased solubility in aqueous medium. Furthermore, addition of
zein was proven to be capable of dramatically increasing hemocompatibility of
silver-loaded
antiseptic agents. Therefore,
silver-
zein composites prepared in this work may find applications in
wound care and food packaging areas.