A comparison of methods to assess the antimicrobial activity of nanoparticle combinations on bacterial cells

Claire Bankier, Yuen Cheong, Suntharavathanan Mahalingam, Mohan Edirisinghe, Guogang Ren, Elaine Cloutman-Green, Lena Ciric

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)
92 Downloads (Pure)


BACKGROUND: Bacterial cell quantification after exposure to antimicrobial compounds varies widely throughout industry and healthcare. Numerous methods are employed to quantify these antimicrobial effects. With increasing demand for new preventative methods for disease control, we aimed to compare and assess common analytical methods used to determine antimicrobial effects of novel nanoparticle combinations on two different pathogens.

METHODS: Plate counts of total viable cells, flow cytometry (LIVE/DEAD BacLight viability assay) and qPCR (viability qPCR) were used to assess the antimicrobial activity of engineered nanoparticle combinations (NPCs) on Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria at different concentrations (0.05, 0.10 and 0.25 w/v%). Results were analysed using linear models to assess the effectiveness of different treatments.

RESULTS: Strong antimicrobial effects of the three NPCs (AMNP0-2) on both pathogens could be quantified using the plate count method and flow cytometry. The plate count method showed a high log reduction (>8-log) for bacteria exposed to high NPC concentrations. We found similar antimicrobial results using the flow cytometry live/dead assay. Viability qPCR analysis of antimicrobial activity could not be quantified due to interference of NPCs with qPCR amplification.

CONCLUSION: Flow cytometry was determined to be the best method to measure antimicrobial activity of the novel NPCs due to high-throughput, rapid and quantifiable results.

Original languageEnglish
Article numbere0192093
Pages (from-to)e0192093
Number of pages13
JournalPLoS ONE
Issue number2
Publication statusPublished - 1 Feb 2018


Dive into the research topics of 'A comparison of methods to assess the antimicrobial activity of nanoparticle combinations on bacterial cells'. Together they form a unique fingerprint.

Cite this