Amélioration du dosage des protéines neurodégénératives par un contrôle des propriétés de surface du puits de dosage

Nombreuses sont aujourd hui les maladies neurodégénératives (Creutzfelt-Jacob, Parkinson, Alzheimer, Lewis), c est-à-dire touchant le système nerveux, dont la cause et la détection restent des sujets de recherches actuels. Ces maladies se traduisent par l apparition, entre autre dans le système sanguin et nerveux, d une protéine antigénique spécifique à chaque affection. Bien que les symptômes permettent leur détection, seule l autopsie donne lieu à un diagnostic de certitude. En effet, la concentration de l agent pathogène étant en quantité maximale lors du décès, la confirmation de la maladie n est exacte que par analyses post-mortem. A l heure actuelle, le dosage de l antigène est réalisé à l aide d une méthode de détection immunoeznymologique appelée ELISA (Enzyme Linked ImmunoSorbent Assays). Malgré son efficacité reconnue, cette méthode ne possède pas une sensibilité suffisante à la détection de la protéine antigénique en faible concentration, c est-à-dire à un stade ante-mortem. Son efficacité dépend de la faculté d attachement d un anticorps primaire à la surface des supports de détection. De cette accroche dépend la capture de l antigène. Pour se faire, une idée originale est de modifier la surface du matériau d analyse sans changer ses propriétés intrinsèques. Ceci dans le but de les rendre biocompatibles et d améliorer l accroche de l anticorps de capture sur la surface en la rendant plus spécifique tout en réduisant les adsorptions aspécifiques des autres biomolécules mises en jeu et responsables d un bruit de fond parasite.LE MANS-BU Lettres (721812108) / SudocSudocFranceF

Increasing the Detection Limit of the Parkinson Disorder through a Specific Surface Chemistry Applied onto Inner Surface of the Titration Well

peer reviewedThe main objective of this paper was to illustrate the enhancement of the sensitivity of ELISA titration for neurodegenerative proteins by reducing nonspecific adsorptions that could lead to false positives. This goal was obtained thanks to the association of plasma and wet chemistries applied to the inner surface of the titration well. The polypropylene surface was plasma-activated and then, dip-coated with different amphiphilic molecules. These molecules have more or less long hydrocarbon chains and may be charged. The modified surfaces were characterized in terms of hydrophilic—phobic character, surface chemical groups and topography. Finally, the coated wells were tested during the ELISA titration of the specific antibody capture of the α-synuclein protein. The highest sensitivity is obtained with polar (Θ = 35°), negatively charged and smooth inner surface.Differential diagnosis of Neurodegeneratives disorder

ETUDES PHYSICO-CHIMIQUES D'UN SUBSTITUT OSSEUX INJECTABLE ET DEVELOPPEMENTS D'HYDROGELS DURCISSABLES IN VIVO. (SPECIALITE (CHIMIE DES BIOMATERIAUX))

NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Synthesis and general properties of silated-hydroxypropyl methylcellulose in prospect of biomedical use.

International audienceSynthesis of grafting silane on a hydro soluble cellulose ether (HPMC) was described. In alkaline medium, this derivate is under gel form. With a decrease of the pH, a self-hardening occurs due to the silanol condensation. For potential biomedical use, we described the silated-HPMC synthesis, the gel behavior after steam sterilization and the parameters of the silanol condensation i.e. pH, silane percentage and temperature. Minimum kinetic of the condensation was observed for pH between 5.5 and 6.5. So temperature catalyzed the reaction and the self-hardening speed was increased by silane percentage

Surface Treatment of Polymeric Materials Controlling the Adhesion of Biomolecules

This review describes different strategies of surface elaboration for a better control of biomolecule adsorption. After a brief description of the fundamental interactions between surfaces and biomolecules, various routes of surface elaboration are presented dealing with the attachment of functional groups mostly thanks to plasma techniques, with the grafting to and from methods, and with the adsorption of surfactants. The grafting of stimuli-responsive polymers is also pointed out. Then, the discussion is focused on the protein adsorption phenomena showing how their interactions with solid surfaces are complex. The adsorption mechanism is proved to be dependent on the solid surface physicochemical properties as well as on the surface and conformation properties of the proteins. Different behaviors are also reported for complex multiple protein solutions

General properties of silated hydroxyethylcellulose for potential biomedical applications.

International audienceThe general properties of hydroxyethylcellulose (HEC) grafted with 3-glycidoxypropyltrimethoxysilane (GPTMS) or 3-glycidoxypropylmethyldiethoxysilane (GPDMS) were studied for potential biomedical applications. The graft involved a Williamson reaction between the free hydroxyl function of HEC and the epoxy function of the two silanes. As the grafted silanes are in ionic form (sodium silanolate), this product remains in gel form at basic pH (>12.3) in aqueous solution. When pH decreases, sodium silanolate is transformed into silanol (2 or 3 silanol functions are carried by silicon, depending on the silane grafted). The silanols interreact, and the gel is transformed into a cross-linking form at room or body temperature. Studies were conducted to optimise this product for specific uses. Steam sterilization was used to compare self-hardening as a function of the silane grafted. Our previous work indicated that HEC grafted with GPTMS has good reactivity, but requires high pH for dissolution, whereas dissolution occurs at lower pH with GPMDS. The rate of silanol condensation for silated HEC was then determined as a function of pH, temperature, type of silane, and the percentage grafted. Condensation rates were ascertained by the viscosity method, and gels were neutralized by different solutions to obtain buffered forms at various pH. The time required to obtain 10(5) mPa x s, with an initial state of 2500 mPa x s, was then calculated. Condensation was catalysed in acid or basic medium at a lower rate at pH 5.5-6.5, and a temperature rise increased the condensation rate, regardless of the pH or silane studied. Silanetriol was more reactive than silanediol. However, as HEC lost considerable viscosity after sterilization, further studies will be conducted to develop new polysaccharides grafted with silane

Interaction between hydroxypropyl methylcellulose and biphasic calcium phosphate after steam sterilisation: capillary gas chromatography studies.

International audienceThe purpose of this study was to check the chemical stability of an injectable bone substitute (IBS) composed of a 50/50 w/w mixture of 2.92% hydroxypropyl methylcellulose (HPMC) solution in deionized water containing biphasic calcium phosphate (BCP) granules (60% hydroxyapatite/40% beta-tricalcium phosphate w/w). After separation of the organic and mineral phases, capillary gas chromatography (GC) was used to study the possible modification of HPMC due to the contact with BCP granules following steam sterilisation and 32 days storage at room temperature. HPMC was extracted from IBS in aqueous medium, and a dialytic method was then used to extract calcium phosphate salts from the HPMC. The percentage of HPMC extracted from BCP was 98.5%+/-0.5%, as measured by UV. GC showed no chemical modifications after steam sterilisation and storage

Surface Engineering and Cell Adhesion

Cell adhesion is a multi-process phenomenon involving physical, physico-chemical and biological mechanisms. The complexity of interfaces is the reason why progress in the theory of cell adhesion has been slow. Greater understanding of interaction mechanisms has been enhanced by complete knowledge of supports and of biological components, in particular the extracellular matrix, membrane walls, cell multiplication processes and apoptosis. The construction of novel surfaces with strongly hydrophilic or ultrahydrophobic properties has allowed new theoretical advances, while at the same time offering numerous and varied technological applications. These include: • Bioadhesion with mechanical anchoring using ubiquitous surface roughness and deformability of certain micro-organisms. • Physico-chemical bioadhesion or repellence resulting mainly from the energy characteristics of support surfaces. • Processes of sorting and guidance by biomolecules present at the support–biofilm interface, generating biochemical responses that can induce cell multiplication or degeneration (as in cancer), or cell death