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Kincses András
Lab-on-a-chip device for the monitoring of surface charge properties of confluent cell monolayers

Aug 30 - szerda

11:30 – 11:45

Bioszenzorika és bio-nanotechnológia

E28

Lab-on-a-chip device for the monitoring of surface charge properties of confluent cell monolayers

András Kincses¹, Ana R. Santa-Maria^1,#, Fruzsina R. Walter^1,2, László Dér¹, Judit Vígh¹, Sándor Valkai¹, Mária A. Deli¹, András Dér¹

¹ Institute of Biophysics, Biological Research Centre, Szeged, Hungary

^2. Department of Cell Biology and Molecular Medicine, University of Szeged, Hungary

^# Current affiliation: Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA 02115, USA

Lab-on-a-chip devices emerged to play pivotal role in the in vitro modelling of biological barriers. The microfluidic channels combined with integrated electrodes provide controlled environment for the tightly interconnecting cell monolayers of intestinal, pulmonary and vascular models. The convenient and fast measurement of the trans-endothelial/epithelial resistance (TEER) and passive permeability provide important information about the integrity of the cell monolayer under healthy and pathological conditions.

We developed a versatile lab-on-a-chip device that can measure the TEER and the passive permeability and also enables the visual monitoring of the cell monolayer via phase contrast microscopy and immunohistochemistry [1]. The device was standardized under static and dynamic condition (without and with fluid flow, respectively) using epithelial and endothelial barrier models. We studied how the shear stress effects the blood-brain barrier properties and the glycocalyx [2]. The latter is especially important, since it contributes to the high negative surface charge of the luminal surface of the barrier forming cells. The negative surface charge plays crucial role in transport processes, infections and other pathologies, so it is very important to investigate the relationship between the surface charge and the overall barrier function. There are very few studies focusing on the surface charge and all of these measures the zeta potential of cell-suspensions. We upgraded our lab-on-a-chip device with a pair of Ag/AgCl electrodes to monitor the surface charge of confluent monolayers via the measurement of transient streaming potential signals [3].

Acknowledgment

OTKA PD-143268

References

[1] Walter FR, Valkai S, Kincses A, et al (2016) Sens. Actuators, B 222, 1209–1219.

[2] Santa-Maria AR, Walter FR, Figueiredo R, Kincses A, et al. (2021) J. Cereb. Blood Flow Metab. 41, 2201–2215.

[3] Kincses A, Santa-Maria AR, Walter FR, el al. (2020) Lab Chip, 20, 3792–3805.

Nagy Krisztina
Emergence of bacterial phage resistance in complex stress landscapes

Aug 29 - kedd

11:15 – 11:30

Modern biofizikai módszerek

E09

Emergence of bacterial phage resistance in complex stress landscapes

Krisztina Nagy¹, Sarshad Koderi Valappil², Trung Phan³, László Dér¹, Julia Bos⁴, Sophia Winslow⁵, Gábpr Rákhely², Péter Galajda¹ and Robert H. Austin³

¹ Institute of Biophysics, Biological Research Centre, Szeged, Hungary

² Department of Biotechnology, University of Szeged, Hungary

³ Department of Physics, Princeton University, Princeton, NJ, USA

⁴ Pasteur Institute, Department of Genomes and Genetics, Paris, France

⁵ University of Northwestern St. Paul, Roseville, MN, USA

Bacteriophages are the most abundant organisms on Earth in terms of particle numbers. As viruses, they coexist with microbes, playing a fundamental role in microbial diversity, population dynamics, and evolution. Understanding the interaction between phages and bacteria gives us essential information on ecological and evolutionary processes.

Here we used a microfabricated environment to reveal the importance of spatial structure and bacterial clustering in the evolution of resistance in E. coli against bacteriophage T4r. We created a stress landscape where phage titers are distributed across an array of localized metapopulations. Motile bacteria were able to move around and explore the precisely controlled landscape. The growth and distribution of a population were monitored by fluorescence time-lapse microscopy.

In this structured environment, resistant subpopulations emerged and spread from biofilm-like pockets within 1-2 days. After the experiments resistant bacteria were collected and selected by the replica plating method. Whole genome sequencing of insensitive bacterial clones was performed, and characteristic mutations were identified. Changes in the bacteriophage receptor ompC and several biofilm-related genes were found.