Mass-transfer independent long-term implantable biosensors
ImplantSens will develop long‐term stable implantable electrochemical biosensors by overcoming mass‐transport limited sensing schemes. This is the major unsolved problem due to the formation of capsules by the foreign body response upon implantation of a sensor. ImplantSens will not only contribute to the painless long‐term monitoring of glucose levels for diabetic patients but also to the development of future implantable sensors for the management of other chronic diseases.
11 ESR will be engaged in all tasks of this scientific chain, thus being trained in the fundamentals of bioelectrochemistry, enzyme engineering, electrode design as well as biocompatibility. Training of the fellows will be performed via an innovative program based on a blended learning concept and will take place at the host institutions, via secondments, workshops, schools and e-learning elements. The scientific training will be completed by training of complementary skill with respect to management, fund raising, IPR and scientific communication. The consortium consists of 7 leading scientists in Europe with the necessary expertise to target this ambitious goal supported by 4 SMEs. ÍmplantSens will improve the availability of a highly skilled workforce for European industries and research strongly needed for at the beginning of the 4th industrial revolution.
Modelling of Porous Electrodes for an Optimized Material Design
This project is dedicated to a bottom-up approach to optimize the design of porous electrode materials devoted to biofuel cells and biosensors. These devices operate on the basis of complex enzymatic electrochemical redox reactions coupled to mass transfer of substrates (glucose and O2) and electron transfer within the pores of the structure and from/to the pore surfaces. The advantage of using porous materials for these devices lies in the very large internal surface area (where electron exchange takes place) to overall material volume ratio, yielding much larger current densities than on a simple solid bare electrode.
The global performance of the electrode is intimately related to the choice of the reagents and the placement within the pore structure but, above all, to the architecture of the material at the pore-scale. However, these materials have always been designed so far on an empirical basis regarding the thickness of the material and its pore size and organization. These parameters have a crucial impact on the competition between mass transport, enzymatic turn-over and heterogeneous electron transfer rate. A rational approach is hence really needed, based on a direct interplay between materials design and modelling to reach optimal performance.
The objective of the present project is four-fold. In a first step, careful models will be derived at the pore-scale. For tractable computational subsequent treatment, macroscale models will be obtained by upscaling their pore-scale analogues. Solutions of the pore-scale models, obtained from Direct Numerical Simulations on simple porous structures, will be compared to the solution of the corresponding up-scaled model as a validation step of the upscaling process. Validation of the overall modelling approach will be further performed by comparisons with experimental results using images of the real structure. In a second step, the electrode current-to-potential dependency with respect to the microstructure obtained by modelling will be exploited to optimize the porous architecture. In a third step, engineering of electrode prototypes, based on the resulting optimized materials, will be then carried out by conveniently tuning the pore structure. In the final part of the project, after a key step of enzymes (and electron mediator) immobilization within the porous structure to achieve a DET or MET operating mode, experiments on the synthetized electrodes will be performed using electroanalytical tests. This recursive and rational approach should lead to a real and decisive breakthrough in the efficiency improvement of the bio-devices to which these porous electrodes are dedicated.
A. Kuhn, M. Heim
In this book chapter, we present an comprehensive overview about the elaboration of highly-ordered macroporous electrodes. We also discuss in detail their physico-chemical characterisation and their potential applications.
MULTIMODAL SENSING POLYMER TRANSISTORS FOR BIOELECTRONICS (ANR MULTISPOT, 2017-2021)
The generation of NOVEL MATERIALS TO HARNESS THE POWER OF BIOLOGICAL SYSTEMS as primary sensors is extremely attractive: rapid cellular signal treatment and amplification by cellular algorithms provides high specificity and sensitivity. ELECTRICAL ACTIVITIES FORM THE BASE OF KEY EVENTS such as brain activity, heart beat or hormone secretion and can be connected to command lines for actuators. Signals are precisely shaped over time via the in- and outflow of distinct ion species through specific plasma membrane channels.
Development of HUMAN “ORGAN-ON-CHIP” DEVICES provides unique opportunities for drug screening and diagnostics on patient derived stem cells. Growth of the global Organ-On-Chip market is impeded by capturing probe/gene free “native” signals for small sample and analyte volumes. Electrophysiology could provide a very appealing solution. However, whereas imaging has gone through a revolution, electrophysiology has not evolved to the same level. Characterizing electrical activity remains complex due to expensive equipment and demanding technicity. Probe-free techniques resolving single action potentials and grouped electrical activity could bring electrophysiology to non-specialized laboratories.
FLEXIBLE ORGANIC ELECTRONICS is particularly suited for interfacing with tissues/cells as ORGANIC ELECTROCHEMICAL TRANSISTOR (OECT). Their mixed electronic/ionic conductivity decreases impedance with richer electrical recordings and local signal amplification with unprecedented signal-to-noise ratio. This should allow use not only in neuronal or cardiac cells, but also in other excitable cells with notoriously small signal amplitude, but known to be excellent sensors and involved in important chronic diseases (islet b-cells, vascular cells, eg.).
RENDERING OECTS SPECIFIC FOR DISTINCT IONS would greatly improve analytical power as did different fluorescent protein “colors” for imaging. However, existing “ion-selective electrodes” are combinations of ion selective membranes and conducting polymers. They do not combine metal ion sensing AND electronic transduction, which would increase specificity, detection limits and printability for large scale production.
WE THEREFORE PROPOSE, based also on preliminary results (i) to develop MULTIMODAL ION-SENSING POLYMERS as well as ION-SENSING POLYMER NANOSTRUCTURES, (ii) to ENGINEER OECT ARRAYS as disposable, non-invasive devices for detection of electrical cell activity and specific ion fluxes, (iii) to DEMONSTRATE THEIR POTENTIAL IN MULTIMODAL MICRO-ORGAN RECORDING of electrical cell activity and specific ion fluxes.
Our group is part of the Institute of Molecular Sciences (ISM) of the University of Bordeaux and is located at the Graduate School of Chemistry, Biology and Physics (ENSCBP). The main activities are focused on the development of new analytical tools and techniques with a special accent on miniaturized systems applied to the study of biological systems and biomedical issues. Our research addresses problems resulting from the ever increasing demands of our modern society concerning various aspects like public health, security and environmental issues.
Distinguishing molecules with almost identical physico-chemical properties, tracking their evolution with a high spatio-temporal resolution, detecting them at the cell or subcellular level in complex environments, are some of the challenges that we work on. Current projects include biofunctionalized nanoparticles, chemical sensors for Biology, electrochemistry of biosystems, micro/nanoscale imaging and smart functional nanostructures. In order to work successfully on these topics, our group is an interdisciplinary team with know-how ranging from Electrochemistry and Optics to organic or colloidal synthesis and Cell Biology. The resulting synergy is the guarantee for solutions to some of the current problems in the field of Analytical Chemistry.
Enjoy your visit and feel free to contact us if you have questions of any kind !
The NSysA research team
21 December 2019
18 November 2019
18 November 2019