IFIS - LITORAL   24734
INSTITUTO DE FISICA DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Detection of lipid bilayer formation in macroporous Silicon by EPR spectroscopy
Autor/es:
X. LEÓN; L. FORZANI; F. GARCÉS; P.M. RODI; E. OSORIO; R.R. KOROPECKI; A.M. GENNARO
Lugar:
Sierra de la Ventana (Buenos Aires)
Reunión:
Congreso; XLIII Reunión Anual de la Sociedad Argentina de Biofísica; 2014
Institución organizadora:
Sociedad Argentina de Biofísica
Resumen:
Spin label EPR spectroscopy was used to study the pore
filling of macroporous silicon with DMPC liposomes. Macroporous samples having
a thickness of around 13 μm, and nearly cylindric pores of 1.0-1.2 μm diameter
were obtained by electrochemical anodization of p-type silicon wafers, in
darkness. The samples were oxidized in a NaOH solution, in order to turn
hydrophilic the inner surface of the pore network. Then, the pore structure was
filled with an aqueous solution of 100 nm unilamellar DMPC liposomes including
2 mole percent of the spin label 5-SASL. EPR spectra were acquired in X band at
30ºC after different incubation procedures. While liposomes have isotropic EPR spectra,
the spectra of lipids inside porous samples when B is parallel to the pore axis
were different from those with B perpendicular to the axis. Simulations of the
spectra indicate that cylindrical lipid bilayers were formed covering the inner
surface of the pores, although some liposomes remain. Diverse protocols were
explored in order to achieve an adequate lipid hydration. We propose the use of
a 2D photonic crystal made of macroporous silicon, which can sense changes in
the dielectric function of the filling material, to study the effects of
confinement on DMPC phase transition.