qNano analysis of Bacterial Biofilm Production at George Mason University

Monique vanMonique Van Hoek, Ph.D., Associate Professor, National Center for Biodefense and Infectious Diseases, George  Mason University. 

Researchers at the National Center for Biodefense and Infectious Diseases, George Mason University recently received the qNano which they used in a new paper, Chung et al. 2014 "Chitinases Are Negative Regulators of Francisella novicida Biofilms" (Open Access).

Dr. Monique Van Hoek and colleagues determined the relative surface charge and size distribution analysis of wild-type Francisella novicida bacteria, and two chitinase mutants chiA and chiB using the device. The qNano utilizes Tunable Resistive Pulse Sensing technology to allow for a high-throughput, particle-by-particle, analysis of particle size, surface charge, and electrophoretic mobility.

qNano experiments were performed to determine if there were observable changes in size of Francisella novicida bacteria that did or did not express chitinase. Chitinase is thought to regulate biofilm expression, which may coat the bacteria with extracellular polymeric substance (EPS) in the absence of chitinase and thus alter their size.


The size distribution and relative surface charge analysis was performed using Izon Control Suite software. See Figures above. The authors found increased bacterial sizes and larger pore translocation times in chi mutants, suggesting that chitinases are involved in changes of the cell sizes and surface charges. In future studies, the qNano will be used to observe the sizes and the surface changes (zeta potential) in bacteria following treatment with antimicrobial peptides being studied.

TED talk: Healed by a Crocodile: the Search for New Antibiotics: Monique L. van Hoek.

Photo: Dr. Monique L. van Hoek and Dr. Myung-Chul Chung, School of Systems Biology and the National Center for Biodefense and Infectious Diseases, George Mason University, Virginia, USA.