CONICET | Buscador de Institutos y Recursos Humanos

The analysis of the modulation of GABAA receptor activity trough molecular environment requires the reconstitution of a purified receptor in a model membrane. Affinity purification would be possible by means of surfaces functionalized with a specific ligand. With this aim, benzodiazepines alkylated derivatives (BA) were designed and characterized previously 1, 2. In the present work we report: a) the synthesis of a new BA with the ability of binding covalently to glass and b) the development and characterization of surfaces coated with two different BAs. To stabilize the BA on the glass surface two strategies (Langmuir-Blodgett, LB, and self-assembled monolayers, SAM) were applied. a) A Si-dodecylclonazepam (SiDC) capable to bind covalently to glass was synthesized. SiDC synthesis was initiated with Clonazepam, 1,12-dibromododecane and 3-aminopropyl triethoxy silane with triethylamine and dioxane as solvents. The yield was 20 % approximately. 1H and 13C NMR spectra allowed the chemical characterization of the products. b) the previously synthesized BA (Br-dodecylclonazepam, BDC)1 was deposited on a glass solid support by the LB technique starting from a Langmuir film which was transferred onto the solid support at constant lateral pressure. The film composition (8 mole% BDC) was chosen from compression isotherms of BDC-dpPC mixtures studies which exhibited full miscibility up to xBDC= 0.1 2. A similar procedure was followed with mixtures containing the fatty acid 1-Br-dodecil, a BA synthetic precursor. In the case of SiDC, the coating of the glass surface was performed through the SAM technique by incubating the glass for 5 days at room temperature with constant stirring in SiDC formic acid solution. The characterization of the modified surfaces obtained by both methods was performed by ATR and AFM. SiDC improved significantly the stability of the coating as compared with BDC. Thus, SiDC SAMs represent a promising system which encourages future studies on R-GABAA purification by a affinity-dependent precipitation method