Antimicrobial Spray-dried Nanoparticles-in-Microspheres

ALBERTO BALDELLI, Hale Oguzlu, Hashem Etayash, Robert Hancock, Feng Jiang, Anubhav Pratap-Singh, The University of British Columbia

     Abstract Number: 7
     Working Group: Nanoparticles and Materials Synthesis

Abstract
Bacterial infections are treated with antibiotics; however, bacteria can develop antibiotic resistance, leading current researchers to explore alternative strategies. Spray-dried nanoparticle-in-microsphere formulations, made of aluminum oxide nanoparticles (Al2O3 NPs), zinc oxide (ZnO), zinc oxide NPs (ZnO NPs) and cellulose nanocrystals (CNCs), with effective antimicrobial and antibiofilm activity against Gram-negative and Gram-positive bacteria are described. We validated that the antimicrobial properties of metal oxide nanoparticles-in-microspheres is higher than each of the raw materials used in any formulation tested. We verified the impact of the ratios in the components of the formulations on the antimicrobial properties and toxicity of metal oxide nanoparticles-in-microspheres. A formulation made of CNCs (weight % ≥ 0.75%) and an equal weight % of Al2O3 NPs and ZnO NPs (~ 0.25% per type of NPs) generated the highest antimicrobial and antibiofilm activity (Gram-positive bacteria (both methicillin-resistant Staphylococcus aureus (MRSA) USA300 LAC, and MRSA SAP0017) and Gram-negative bacteria, including E. coli ATTC489, P. aeruginosa PAO1, and Acinetobacter baumannii ATTC5015). Moreover, the toxicity of these formulations, tested against peripheral blood mononuclear cells, was very minimal (≤500 µg/ml) and significantly lower than the toxicity of the metal oxide NPs when tested alone.