Abstract
<title>Abstract</title> <p> A supervised machine learning model has been used to classify eight representative microorganisms—Amoeba, Euglena, Hydra, Paramecium, rod-shaped bacteria, spherical bacteria, spiral bacteria, and yeast—with 98% accuracy and high F1-scores (0.98–0.99). After successful classification of the microorganisms, a nontoxic nanosystem of stabilized tetragonal and cubic ZrO₂ have been developed that can be used as potent antimicrobial agent and a biocompatible nanocarrier for antimicrobial drug delivery. To develop such potent nanosystem, a fully transparent colorless Al <sup>3+</sup> modified ZrO(OH) <sub>2</sub> ⋅xH <sub>2</sub> O gel has been developed by a chemical method of Al-metal surface hydrolysis in aqueous solution of zirconium oxychloride at room temperature. After that, Al <sub>2</sub> O <sub>3</sub> (Al <sub>2</sub> O <sub>3</sub> content ≤ 5 mol %) stabilized ZrO <sub>2</sub> nanoparticles have been synthesized in a metastable t-ZrO <sub>2</sub> phase by a reconstructive thermal decomposition of this amorphous hydroxyl transparent gel in air at temperature 500 °C. The t-phase of ZrO <sub>2</sub> changes to c-phase with the increase in Al <sub>2</sub> O <sub>3</sub> content (Al <sub>2</sub> O <sub>3</sub> content ≥ 10 mol %). The phase formation in Al <sub>2</sub> O <sub>3</sub> stabilized metastable t- or c-ZrO <sub>2</sub> nanoparticles has been revealed by X-ray diffraction study of the specimen before and after annealing at temperature 500 °C. No independent Al <sub>2</sub> O <sub>3</sub> recrystallizes in a perfect Al <sub>2</sub> O <sub>3</sub> : ZrO <sub>2</sub> solid solution. This present work may show a new perspective in both the classification of the microorganisms and development of a new biocompatible nanosystem that can be used as antimicrobial agent and in antimicrobial drug delivery. Future work will focus on detailed antimicrobial and drug targeting studies of this nanosystem. </p>