RESUMO
Aminosilane film on mica is investigated in this work for further use as a substrate for DNA immobilization. We study the deposition of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPS) on mica surfaces by atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle measurements. Deposition both in aqueous solution and in vapor-phase is explored. In aqueous solution, it is found that the interactions of molecules with the mica surface are pH-dependent. In the case of vapor phase deposition, a multilayer film composed of a first monolayer and successive bilayers is obtained. This is the first observation of the organization of aminosilane films on mica.
Assuntos
Silicatos de Alumínio/química , DNA/química , Propilaminas/química , Silanos/química , Concentração de Íons de Hidrogênio , Microscopia de Força Atômica , Conformação Molecular , Espectroscopia Fotoeletrônica , Elastômeros de Silicone , Propriedades de SuperfícieRESUMO
We have studied the phase transitions of a phospholipidic single-bilayer supported on a mica substrate by real-time temperature-controlled atomic force microscopy. We show the existence of two phase transitions in this bilayer that we attribute to two gel (L(beta))/fluid (L(alpha)) transitions, corresponding to the independent melting of each leaflet of the bilayer. The ratio of each phase with temperature and the large broadening of the transitions' widths have been interpreted through a basic thermodynamic framework in which the surface tension varies during the transitions. The experimental data can be fit with such a model using known thermodynamic parameters.