Characterization of unilamellar DPPC membrane over Ag nanoparticules by SERS

DOLY MARIA CHEMES; CARLOS MAURICIO BUSTAMANTE; ROSA MARIA S.ALVAREZ

Tucumán

Congreso; III Latin American Federation of Biophysical Societies (LAFeBS) IX IberoAmerican Congress of Biophysics XLV Reunion Anual SAB 2016; 2016

Sociedad Argentina de Biofísica

Surface enhanced Raman spectroscopy (SERS) is a technique that enhances in several orders of magnitude the Raman signals of molecules adsorbed on nanostructured metallic substrates, allowing the detection of low concentrations of analytes and even traces of them. In the last decades, this technique has been amply extended to the detection of biomolecules. Rapid label-free identification of small target analytes by the ?fingerprint? type spectra makes SERS adequate for the detection of a broad range of biomolecules of interest, as phospholipids. Even though Raman spectroscopy has been extensively used for the study of lipids, this area is relatively new and emergent for SERS (1).We studied unilamellar lipid membranes by SERS, using a suspension of Ag nanoparticules (AgNPs), which were covered with a bilayer of dipalmitoylphosphatidylcholine (DPPC) (2). To obtain hot spots for SERS we deposited the DPPC-AgNPs over a filter means according to an already published protocol (3), but introducing some modifications. The SERS spectrum of DPPC unilamelar membrane shows a decrease on its fluidity compared to multilamellar systems, and a notorious enhancement of vibrational modes of the head polar groups relative to those of hydrocarbon chain.AgNPs covered with DPPC were characterized, before and after deposition over the filter means, by TEM and SEM respectively. Also AgNPs were characterized by UV-Vis spectroscopy.The importance of studying lipids disposed in this kind of nano-liposome lies on its potential use for biosensing applications.Referencias(1) K. C. Bantz, A. F. Meyer, N. J. Wittenberg, H. Im, Ö. Kurtuluş, S. H. Lee, N. C. Lindquist, Sang-Hyun Oh, C. L. Haynes. Phys. Chem. Chem. Phys., 2011, 13(24), 11551-11567.(2) H. Barani, M. Montazer, T, Toliyat, N. Samadi. Journal of Liposome Research, 2010, 20(4),