Synthesis and characterization of zein-chromium nanoparticles with antibacterial effects

Antibiotic resistance is a major problem of modern medicine. Due to the ability of Gram-negative bacteria to develop resistance against antibiotics, novel therapeutic strategies are emerging based on nanomaterials that perform a controlled release of antibacterial agents that don't promote resistance. Protein nanoparticles are good candidates for this approach because they are biocompatible, biodegradable and non-toxic. Zein is a protein from corn that is able to assemble into nanoparticles. Zein nanoparticles loaded with essential oils, plant extracts or with silver nanoparticles presented a good stability and superior antibacterial effects. Taking into account that trivalent chromium ions (Cr3+) conjugated with amino acids have antibacterial and antifungal activity, here we have synthesized and tested the antibacterial effect of zein nanoparticles loaded with Cr3+ against two E. colt strains with different antibiotic resistance profiles. The nanoparticles that we synthesized are 20-50 nm in size. While zein nanoparticles without Cr3+ have no antibacterial effect, chromium-zein nanoparticles inhibit the growth of the two strains and the biofilm formation. Given the effectiveness of chromium-zein nanoparticles against bacterial strains with resistance to different classes of antibiotics and the advantages offered by zein, these are good candidates for diverse biomedical applications.