Ph.D.
Nguyen Huu Ngoc
Faculty of Medical Technology, Van Lang University, HCMC
Title: Advanced microscopy for understanding bacterial damage pathways from cell death quantification to morphological and biomolecular alterations
Nguyen Ngoc Huu1,2, Nguyen Anh Duc3, Tan Phuoc Ton2, Truong Thi Bang Chau4, Le Van Chuong1
1Faculty of Medical Technology, Van Lang University, Ho Chi Minh 70000, Vietnam
2Biomedical nanoengineering laboratory, College of medicine and Public Health, Flinders University, SA 5042, Australia.
2Faculty of Sciences, Engineering and Technology, Adelaide University, Adelaide, South Australia 5005, Australia
3Faculty of Traditional Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City 70000, Vietnam
Understanding antibacterial activity requires measuring bacterial reduction and direct evidence of how bacteria and biofilms are damaged at structural, and biochemical levels. Conventional assays such as CFU counting and optical density measurements provide useful endpoint data, but they cannot explain whether bacterial killing is associated with membrane disruption, oxidative stress, biofilm collapse, morphological damage, or biomolecular alteration. Representative antibacterial metal-based nanoparticles with (MIC 5µg/ml) are used as case studies to demonstrate how microscopy-guided analysis can link bacterial killing to membrane damage, oxidative stress, biofilm disruption, morphological deformation, and biomolecular alterations. The result from confocal laser scanning microscopy (CLSM) provides a functional and spatial platform to assess bacterial viability, physiological stress, and biofilm architecture. Furthermore, CLSM z-stack imaging further allows measurement of biofilm thickness, biomass, biovolume, surface coverage, and structural disruption using software such as ZEN, ImageJ/Fiji or IMARIS. Additional fluorescence probes, including CellROX Green or DCFH-DA for intracellular reactive oxygen species and DiBAC4(3) for membrane depolarisation, can provide mechanistic evidence of oxidative stress, membrane potential disruption, and compromised membrane integrity. Scanning electron microscopy (SEM) complements these functional observations by revealing bacterial morphological damage. SEM can visualise surface wrinkling, shrinkage, rupture and altered cell morphology. Synchrotron macro ATR-FTIR microspectroscopy adds a label-free biochemical dimension by mapping biomolecular alterations in treated bacteria and biofilms. Lipid ester bands around 3000–2800 and ~1740 cm-1 indicate membrane lipid changes; amide I/II regions around 1700–1500 cm-1 reflect protein alterations; phosphate bands around 1250–1080 cm-1 suggest nucleic acid or phospholipid disruption; and carbohydrate bands around 1200–900 cm-1 indicate extracellular polymeric matrix remodelling. Together, CLSM, SEM, and synchrotron macro ATR-FTIR microspectroscopy link bacterial killing to spatial viability loss, oxidative and membrane stress, morphological damage, and biochemical alterations.
Keywords: Antibacterial mechanisms; advanced microscopy; confocal laser scanning microscopy; scanning electron microscopy; synchrotron macro ATR-FTIR microspectroscopy; biomolecular alterations.
Biography of the presenting author
Dr Ngoc Huu Nguyen received his PhD in Biomedical Engineering from The University of Sydney, Australia, where his doctoral research focused on antimicrobial biomaterials for tissue engineering. He was a Research Associate at Flinders University, Australia, and is currently a Lecturer in the Faculty of Medical Technology at Van Lang University, Vietnam. His research focuses on multifunctional biomaterials, antibacterial nanomaterials, and advanced microscopy-based analysis of antibacterial mechanisms.
Dr Nguyen has published more than 40 peer-reviewed journal articles. His research combines microbiology, biomaterials engineering, and advanced characterisation techniques, including confocal microscopy, SEM, FIB-SEM, TEM, AFM, proteomics, and synchrotron ATR-FTIR microspectroscopy, to investigate bacterial viability, biofilm disruption, membrane damage, oxidative stress, and biochemical alterations in pathogens. His broader research vision is to develop next-generation antibacterial and regenerative biomaterials with strong mechanistic understanding and translational potential.
Presenting author details
Full name: Ngoc Huu Nguyen
Contact number: 0939616968
Email: huu.nn@vlu.edu.vn
LinkedIn: https://www.linkedin.com/in/ngoc-huu-nguyen-ph-d-m-sc-b-eng-4176a0110/
Researchgate: https://www.researchgate.net/profile/Ngoc-Huu-Nguyen
Google Scholar: https://scholar.google.com/citations?user=Qd_HSOYAAAAJ&hl=vi
ResearcherID: OXB-3151-2025
ORCID: https://orcid.org/0000-0002-9927-4866
Website: https://www.vlu.edu.vn/faculty/khoa-ky-thuat-y-hoc
Session name/ number: 2
Category: Oral presentation