Microwave-synthesized NiZrO3@GNP and NiZrO3@MWCNT nanocomposites: enhanced antimicrobial efficacy against biofilms and Mycobacterium smegmatis.

The persistent challenge posed by antibiotic-resistant bacteria and tuberculosis necessitates innovative approaches to antimicrobial treatment. This study explores the synthesis and characterization of NiZrO₃ nanoparticles integrated with graphene nanoplatelets (GNP) and multi-walled carbon nanotubes (MWCNT), using a microwave-assisted green synthesis route, employing fenugreek (Trigonella foenum-graecum) seed extract as a gelling agent. The synthesised nanocomposites were systematically analyzed using XRD, FT-IR, Raman spectroscopy, HR-SEM and HR TEM analysis to assess structural, optical, and morphological properties. The antimicrobial and antibiofilm efficacy was evaluated against drug-resistant strains, including Escherichia coli and Klebsiella pneumoniae, by well diffusion method and crystal violet-Microtitre plate (CV-MtP) method. Notably, the NiZrO₃@MWCNT composite exhibited a maximum antibacterial inhibition zone of 13 mm and showed superior biofilm inhibition of 92.8% against K. pneumoniae at 500 ppm. In contrast, NiZrO₃@GNP demonstrated a biofilm inhibition of 97% at 500 ppm. Furthermore, the microplate Alamar Blue assay (MABA) was employed to determine the minimum inhibitory concentration (MIC) against Mycobacterium smegmatis (MTS) with NiZrO₃@MWCNT achieving 96% inhibition and at 500 ppm. These results confirm the enhanced antimicrobial efficacy of the carbon-integrated nanocomposites over pure NiZrO₃, which showed limited activity. This research underscores the promise of NiZrO₃-based nanocomposites as advanced antimicrobial agents, offering a novel strategy to combat the global health threat of antibiotic resistance.

Supplementary information: The online version contains supplementary material available at 10.1007/s13205-024-04201-5.