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Stéphane Marinesco, responsable de la plate-forme NeuroChem, Centre de Recherches en Neurosciences de Lyon (CRNL), Inserm U1028, CNRS UMR5292 et Université C. Bernard (Lyon I).
Résumé :
A large variety of biosensors is now used in biomedical settings to provide fast and simple measurements of physiological parameters at the bedside of patients or in laboratory animals. Among all biosensor devices that have been developed for medical applications, glucose biosensors are probably the best known to the public and represent a multi-billion dollar market. These biosensors can now be directly implanted in the human body, providing online continuous measurements and eliminating the need for drawing blood samples. I will briefly review the state of the art for such implantable glucose biosensors. I will then focus on biosensor devices that can be implanted in the brain of laboratory animals. Such devices are based on microelectrodes that minimize tissue lesions and use natural enzymes for biological recognition. Such microelectrode biosensors are currently used for detecting neurotransmitters and metabolites, and decipher the mechanisms of chemical communication in the brain. I will review the structure of the brain parenchyma with the intracellular, extracellular and vascular compartments. I will then discuss the specific problems related to the implantation of a probe into the brain, also known as the foreign body response, and the overall interest of invasive measurements compared to non-invasive methods such as optical microscopy or magnetic resonance imaging. I will finish by an overview of the engineering and fabrication of microelectrode biosensors and by a discussion of recent results obtained in our laboratory regarding their specificity for neurotransmitter detection.