Facile biological synthetic strategy to morphologically aligned CeO2/ZrO2 core nanoparticles using Justicia adhatoda extract and ionic liquid: Enhancement of its bio-medical properties

In this study, a typical green synthesis route has approached for CeO2/ZrO2 core metal oxide nanoparticles using ionic liquid mediated Justicia adhatoda extract. This synthesis method is carried out at simple room temperature condition to obtain the core metal oxide nanoparticles. XRD, SEM and TEM studies employed to study the crystalline and surface morphological properties under nucleation, growth, and aggregation processes. CeO2/ZrO2 core metal oxides display agglomerated nano stick-like structure with 20-45 nm size. GC-MS spectroscopy confirms the presence of vasicinone and N,N-Dimethylglycine present in the plant extract, which are capable of converting the corresponding metal ion precursor to CeO2/ZrO2 core metal oxide nanoparticles. In FTIR, the corresponding stretching for Ce-O and Zr-O bands indicated at 498 and 416 cm(-1) and Raman spectroscopy also supports typical stretching frequencies at 463 and 160 cm(-1). Band gap energy of the CeO2/ZrO2 core metal oxide is 3.37 eV calculated from UV- DRS spectroscopy. The anti-bacterial studies performed against a set of bacterial strains the result showed that core metal oxide nanoparticles more susceptible to gram-positive (G +) bacteria than gram-negative (G-) bacteria. A unique feature of the antioxidant behaviors core metal oxides reduces the concentration of DPPH radical up to 89%. The CeO2/ZrO2 core metal oxide nanoparticles control the S. marcescent bio-film formation and restrict the quorum sensing. The toxicology behavior of CeO2/ZrO2 core metal oxide NPs is found due to the high oxygen site vacancies, ROS formation, smallest particle size and higher surface area. This type of green synthesis route may efficient and the core metal oxide nanoparticles will possess a good bio-medical agent in future.