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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:08 |
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Conference: Bucharest University Faculty of Physics 2009 Meeting
Section: Biophysics; Medical Physics
Title:
Biodynamics: physical ways and means to analyze biosystems towards biosensing
Authors:
Eugen Gheorghiu
Affiliation:
International Centre of Biodynamics, ICB, Bucharest, Romania
www.biodyn.ro
E-mail
egheorghiu@biodyn.ro
Keywords:
Biodynamics, Dielectric/Impedance Spectroscopy, Polarizability, Surface Plasmon Resonance, Hybrid sensing platforms
Abstract:
Tremendous progress has been made in the ability to measure/detect particular noxious compounds at very low concentrations. However, evaluation of rare or unknown compounds, metabolites and mixtures presents considerable analytical challenges.
Aiming to appraise non-lethal effects triggered by different (environmental) stimuli, we have developed:
• analytical tools (measuring devices, system modeling & advanced data analysis) which involve combined electro-optical assays and microfluidics, suitable for time based analysis
• hybrid sensing platforms able to integrate recognition elements (affine compounds), lipid membranes and/or cells immobilized on chips.
I will outline ICB recent results on:
1. Dielectric modeling of interconnected cells;
The dielectric behavior of linear clusters of two or more particles connected by tight junctions has been analyzed by a spectral method. The polarizability of the system has been derived as well as the related dependence on the shape of the particles and their electric properties.
2. Monitoring cell cycle by impedance / dielectric assays.
Advancing our previous studies, we have: a) prolonged the length of the time series (duration of cell growth) by preserving the “quality” of the culture medium; b) increased the signal-to-noise ratio by “local” enhancement of cell concentration and c) find an effective way to “freeze” the evolution of a cell suspension on a particular phase of the cell cycle
3. Appraisal the multiphase interaction between a cell lytic agent (melittin) and a lipid membrane.
A novel kinetic model is advanced to relate surface plasmon resonance (SPR) data with actual concentrations of interacting partners. We show that quantitative assessment of the interaction between melittin and a lipid membrane is capable to provide both sensing avenues and detailed mechanistic insights into effects of pore forming compounds. The proposed model combined with appropriate design of the experimental protocol adds a new depth to the classic SPR investigation of peptide - lipid interaction offering a quantitative platform for detection and improved understanding of the manifold facets of the interaction.
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