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Séminaire IBMM

Cytokine detection using flexible BioLab-On-Chip

Prof. Abdelhamid Errachid El Salhi (Institut des Sciences Analytiques – ISA, UMR 5280 CNRS, Université Claude Bernard Lyon 1)

publié le , mis à jour le

Le Lundi 18 février 2013 à 10h
Faculté de Pharmacie, Bibliothèque du DAPP, bâtiment E, 3e étage

Heart failure (HF) is more common in older people, and it is not an inevitable consequence of aging as it can also affect the young. To understand what happens when HF manifests, knowledge of the hearts functional capacity and how it interacts with the rest of the circulatory system is required. As a result, a sensitive, real-time and efficient medical diagnosis has led to growing interest in new innovative tele-control services. This allows the patient and the healthcare professional to control the performance of the cardiovascular implanted assist device (VAD). Biosensors are one of the interesting points in this field that involves the patient monitoring the VAD for the detection of primary inflammatory biomarkers after surgery.

The present work describes a simple technique for the fabrication of a gold microelectrode array with an integrated Ag/AgCl reference microelectrode based on polyimide (PI) which is a flexible and biocompatible thermoplastic substrate. The investigated fabrication technology was based on soft lithography which involved a combination of replica molding (RM) and patterning of a self-assembled monolayer (SAMs), through microcontact printing (µCP). From a fabricated silicon microelectrode mold, an elastomeric stamp of the microelectrodes was replicated in polydimethylsiloxane (PDMS) and inked with octadecanethiol (ODT) for patterning of the gold surface. The non-patterned gold was then removed by selective chemical etching leaving very well defined gold microelectrodes with a high resolution. Finally, the integrated Ag/AgCl reference microelectrode was fabricated by silver electro-deposition onto the gold microelectrode. The developed biosensor was then tested for a medical application by immobilizing both monoclonal antibodies (mAb) ; anti-human interleukin-10 (IL-10) and anti-human tumor necrosis factor-alpha (TNF-a) onto the working electrode surface. Functionalization of the gold microelectrodes was made with carboxyl diazonium through cyclic voltammetry (CV). The multiple detection of the corresponding cytokines was verified by fluorescence, whilst electrochemical impedance spectroscopy (EIS) analysis quantified a detectable IL-10 cytokine concentration from 1-15 pg/mL. This confirmed the bio-recognition between the anti-human mAb (IL-10 and TNF-a) and of its corresponding cytokine. The obtained results show that the mAb were efficiently immobilized and the proteins for human IL-10 were detectable at weak concentrations. The electrochemical measurements were applied on the manufactured gold microelectrodes for 9 hours. This shows a high resistance of the microelectrodes for long-lasting measurements and, therefore, highlights the good adhesion of gold-PI. The results presented here have demonstrated the feasibility of a simple microelectrode fabrication technology with application to a biomedical response.

Keywords :
Soft lithography, self-assembled monolayer, contact printing, polyimide, diazonium, interleukin-10, tumor necrosis factor alpha, impedance spectroscopy, BioLab-on-Chip.

Contact local IBMM : Ange Polidori (équipe Systèmes Amphiphiles, Avignon), Jean-Alain Fehrentz (DAPP, Montpellier Fac. Pharmacie)

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