Zein based magnesium oxide nanowires: Effect of anionic charge on size, release and stability

Magnesium oxide (MgO) is a vital mineral with competence in strong inhibition against resistant bacterial strains. Dosage form design for the MgO particles delivery is limited both due to the fact of poor solubility and instability by agglomeration on storage. Redesigning MgO nanostructured carrier coated by zein having anionic charge as stabilizer would create great prosthetic having antibacterial significance. We expect this innovative technique paves way not just to modify the release of MgO nanowires but can even overcome both the limitations. MgO nanowires were synthesized using microwave hydrothermal technique. Zein coating has exhibited significant effect over physicochemical properties of MgO. The pure MgO nanowires alone exhibited an average size of 150 nm but tend to aggregate increasing their size to 800 nm contrastingly to the zein coated MgO nanowires those average size was found 230 nm with no further size increase on exposure in aqueous dispersion over 1 h. This was supported with the scanning and transmission electron microscopy images that indicated grouped or aggregation of pure MgO nanowires while as highly sharp distinct MgO nanowires when coated with zein. Pure MgO and zein coated nanowires exhibited a surface charge of 11 and -22 mV at pH of 1.2 alternatively -15 and -18 mV at pH 6.8, respectively. X-ray crystallography of zein based MgO nanowires was highly pure and crystalline in nature. The FTIR spectra indicated distinct peaks with no possible interaction or formation of new product during synthesis or with zein. Interestingly, in-vitro dissolution was found prolonged about 20 % up to 12 h for the zein stabilized MgO nanowires at pH 1.2 with respect to pure MgO and zein coated MgO nanowires prepared at pH 6.8 indicating effective adsorption of zein. Degradation temperatures did not indicate any significant changes in physiochemical properties indicating the effect of zein over enhancement of nanowires stability. The use of zein has provided sufficient electrostatic and steric hindrance between nanowires preventing aggregation with altered MgO release. Fabricated zein-coated MgO nanowires are biocompatible and can be promising antibacterial agents in dental materials.