Download Monitoring the extracellular space with catalytic self

Welcome. This page is intended to offer some details about one of our new projects, namely:
Monitoring the extracellular space with catalytic
self-propelled nanomotors (Acronym: Extracell)
Summary
Resources
Personnel
Preliminary
results
Links
Summary:
Classic catalytic nanomotors are bimetallic nanorods (diameter ~ 200-400 nm; length ~ 1-3 μm)
which catalyze the oxidation of hydrogen peroxide on their platinum half and the reduction of
hydrogen peroxide on their gold half. When surrounded by hydrogen peroxide (i.e. “fuel”), such
nanomotors display autopropulsion of which mechanism is still debated and of which rate
depends on the concentration of hydrogen peroxide.
The present project aims to use, for the first time,
such nanomotors to detect compounds which are
secreted into the extracellular space by in vitro cell
cultures. In order to achieve this aim, the catalytic
reactions which propel classic nanomotors will be
replaced by the reactions of enzymes immobilized
on the surface of the nanomotors. The enzymecatalyzed reactions will change the nature and will
reduce the concentrations of the „fuel” required for
autopropulsion. The project will focus on:
1.) Developing enzyme-based nanomotors which
move in the presence of molecules other than
Figure 1. Oxidase-based nanomotor concept we are working
reactive oxygen species (see Figure 1);
on in the present project.
2.) The use of Electrochemical Scanning
Microscope (SECM) to monitor the behavior of enzyme-based nanomotors;
3.) The first attempts to use nanomotors to detect compounds in the extracellular space;
The project will also allow improving the human and material resources of the research team (by
the acquisition of a SECM and the employment of two young researchers). It will thus increase
the chances for a successful participation not only in national but also in European research
project competitions (e.g. ERC).
Resources:
The project is carried out on the premises of the International Centre of Biodynamics and,
first of all, within the Electrochemistry Laboratory of the institute. The laboratory is equipped
with several potentiostats such as VSP potentiostat from Bio-Logic SAS, CellTest System
from Solartron Analytical, and 797 VA Computrace from Metrohm. It also benefits from
access to a Zeiss AxioObserver Z1 microscope equipped with an ANDOR IXon DU-885K
camera , cell culture facilities, a Physical Vapor Deposition 75 system from Kurt J. Lesker
Company, an Evolution 600 spectrophotometer from Thermo Scientific, an Infinite 200 Pro
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microplate reader from Tecan, and a Nanowizard II AFM system from JPK AG (among
others).
The Executive Agency for Higher Education, Research, Development and Innovation
Funding (UEFISCDI) is greatly acknowledged for funding the research project.
Personnel:
The project is carried out by the following researchers:
Szilveszter Gáspár (Ph.D.,
Project Leader)
Mihaela Gheorghiu (Ph.D.)
Sorin David (Ph.D.)
Bunea Ada Ioana (B.Sc.)
Pavel Ileana (B.Sc.)
Preliminary results:
Classic nanomotors, i.e. Au|Pt nanorods, display
autopropulsion in (rather high concentrations of)
hydrogen peroxide. Motivated by this fact we are
currently immobilizing oxidases onto such
nanorods and investigate if the amount of
hydrogen peroxide produced by the immobilized
enzyme (in the presence of its main substrate) is
enough to induce autopropulsion. Change in the
diffusion coefficient induced by the presence of
the substrate is currently considered as
alternative parameter to the speed of the
Figure 2. Mean Square Displacement vs. Time plots are used
autopropulsion induced by the presence of the
to distinguish autopropulsion from diffusive motion as well as
substrate (see Figure 2). Nanorods with diffusive
to calculate the diffusion coefficients characterizing our
enzyme-modified nanorods
motion enhanced by hypoxanthine were
obtained. We are working on the manuscript describing these nanorods. Activities within the
project have resulted in one publication (Gáspár et al., 2013). The evaluation of commercially
available Scanning Electrochemical Microscopes was also started and the purchase of such a
system is planned during 2013.
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Gáspár, S., Marty, J.L., and Gheorghiu, E. (2013). Cytochrome c-Based Amperometric
Sensors for Superoxide Detection: Where Their Signal Comes From? Electroanalysis 25,
448–452.
Links to some groups / departments with similar activities:
Laboratory for Nanobioelectronics (from the Department of Nanoengineering, University
California San Diego, USA)
The Sen Group (from the Department of Chemistry, Pennsylvania State University, USA)
Institute for Integrative Nanosciences (from the Leibniz Institute for Solid State and Materials
Research Dresden, Germany)
The Pumera Group (from the Division of Chemistry & Biological Chemistry, Nanyang
Technological University, Singapore)
Analytical Nanosystems Group (from the Institute of Molecular Sciences, University of
Bordeaux, France)
Summary
Resources
Personnel
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Preliminary
results
Links