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Molecular Approach of Biosensors Elaboration and Test

Biosensors are analytical devices used to detect and quantify a target in a complex environment. They are constituted of a biological or biomimetic element, intimately linked or integrated within a transducer. The biological element ensures the specific and selective detection of the target, which can be antibodies, DNA/RNA strands, enzymes, aptamers etc. The transduction element, often a surface associated with a technique, transforms this biological interaction into a signal that can be measured by the experimenter. A high-performance biosensor is fast, reliable (specific and selective), sensitive, user-friendly and inexpensive. However, like any emerging discipline, the design and manufacture of biosensors remains to be optimized and is often based on non-in-depth tests or empirical protocols since the molecular processes involved remain misunderstood despite the multitude of elementary steps to be controlled, as illustrated in the figure below for the case of Immunosensors.


In our research activity, we apply a molecular approach, associated with a fine physicochemical characterization at each stage of the biosensor development to investigate the different mechanisms involved in the interaction of biomolecules with material surfaces, an approach also used to study the reactivity and efficiency of the resulting biosensor.

In addition, the simplified representation of the biosensor as a surface on which bioreceptors are immobilized often leads to the idea that an improvement in biosensor performance would require an increase in the number of bioreceptors. The reality is of course more complex since it involves combining density, dispersion and accessibility of immobilized bioreceptors (in the direct format) or analytes (when detection is done by competition, a format particularly adapted to the detection of small analytes). In this context too, the understanding of the mechanisms involved allows us, through a molecular approach, to design surfaces that are reliable, reusable and stable over time, as illustrated in the figure below.


We’ve been developing researches in this area for many years and this led us to establish multiple interdisciplinary collaborations, most often to meet societal needs, particularly in the medical and environmental fields. There is no universal surface chemistry or standard biosensor. For each couple (target, receptor), this is a new challenge involving, first, the control of the surfaces of biomolecules as well as those of metal and oxide supports, particularly in terms of composition, charge and conformation, and then establishing the ideal attachment method allowing to preserve the biomolecular reactivity of the receptors while maintaining high density, dispersion and accessibility essential for a high-performance biosensor.


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