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Accueil du site > Productions scientifiques > Thèses > Thèses soutenues > Caractérisation de l’adhésion cellulaire par la technique de la microbalance à quartz.

Caractérisation de l’adhésion cellulaire par la technique de la microbalance à quartz.

Doctoral Research Scientist : Delphine LE GUILLOU

Thesis Director : Marcel GINDRE

Research topic : Characterization of cell adherence monitored by the quartz crystal resonator technique.

University : Université Paris XIII

Date of defense : 2005

Summary :

The Thickness Shear Mode (TSM) quartz crystal resonator has been extensively as sensitive sensor in various electrochemical and biological applications. This technique based on the propagation of an ultrasonic shear weve generated by a sinusoidal electric field through a piezoelectric quartz resonator, provides a non-destructive and powerful means to changes at solid-solid or solid-liquid interfaces. This technique appears to be of great interest in order to study the interactions, which occur at the interface of biomedical devices between proteins and/or cells and polymer or metallic surfaces.

In this study, we coat the quartz surface with bioactive polymers in order to investigate by TSM their ability to inhibit McCoy fibroblast cell adhesion and proliferation. The chosen bioactive polymers are synthetized by radical copolymerization of appropriate monomers bearing defined chemical functions. In vitro studies have demonstrated that the presence of carboxylate and sulfonate groups along these polymers induces a modulation of cell proliferation that directly depends on the value of the ratio R that is equal to the ratio of the carboxylate groups upon the sum of the carboxylate and sulfonate groups. A higher inhibitory effect on cell proliferation was found for polymers exibiting R around 0.57. Such polymers may be used as coatings or grafted on appropriate polymer substrate in order to obtain intraocular lenses (IOL) capable of preventing the appearance of posterior capsule opacification (PCO) also named « secondary cataract », amajor long-term complication after extra-capsular cataract extraction and posterior chamber lens transplantation.

In this work, the TSM is used to assess human cell (McCoy fibroblast) adhesion onto five polymers of various chemical compositions. Polymer PMMA is the control, polymers PB31 and PB32 exhibit only one functional group-carboxylate or sulfonate, while PB27 and PB33a exhibit both carboxylate and sulfonate groups. We show that the resistance measured by the quartz crystal resonator induced by cell adhesion on various surfaces depends on the chemical composition of the polymer.The observed resistance on non-coated quartz (without polymer) was found to be identical to that observed on PMMA, PB31 and PB32 coated quartz whereas it was totally different and strongly lowered on PB27 and PB33a coated quartz. Results show that both groups are necessary to get an inhibiting effect on the resistance. In addition, cell adhesion was observed with three diffrent techniques : quartz crystal resonator, cell counting and fluorescence microscopy. Thus, the quartz crystal resonator technique is very sensitive to evaluate cell/surfaces intercations and it would be acceptable to support or supplant traditional cell counting techniques or microscopy.

First, we optimized the quartz crystal resonator technique for demonstrate that the quartz crystal resonator is sensitive cell adhesion processes. Thus, we show that the quartz crystal resonator is also propotional to cell adhesion number, cell adhesion surface and focal point number.

Keywords : Biosensor, cell adhesion, bioactive polymers, quartz crystal resonator, copolmer, fibroblast

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