title: Surface-enhanced Raman scattering of self-assembled thiol monolayers and supported lipid membranes on thin anodic porous alumina.
abstract: Thin anodic porous alumina (tAPA) was fabricated from a 500 nm thick aluminum (Al) layer coated on silicon wafers, through single-step anodization performed in a Teflon electrochemical cell in 0.4 M aqueous phosphoric acid at 110 V. Post-fabrication etching in the same acid allowed obtaining tAPA surfaces with ≈160 nm pore diameter and ≈80 nm corresponding wall thickness to be prepared. The tAPA surfaces were made SERS-active by coating with a thin (≈25 nm) gold (Au) layer. The as obtained tAPA-Au substrates were incubated first with different thiols, namely mercaptobenzoic acid (MbA) and aminothiol (AT), and then with phospholipid vesicles of different composition to form a supported lipid bilayer (SLB). At each step, the SERS substrate functionality was assessed, demonstrating acceptable enhancement (≥100×). The chemisorption of thiols during the first step and the formation of SLB from the vesicles during the second step, were independently monitored by using a quartz crystal microbalance with dissipation monitoring (QCM-D) technique. The SLB membranes represent a simplified model system of the living cells membranes, which makes the successful observation of SERS on these films promising in view of the use of tAPA-Au substrates as a platform for the development of surface-enhanced Raman spectroscopy (SERS) biosensors on living cells. In the future, these tAPA-Au-SLB substrates will be investigated also for drug delivery of bioactive agents from the APA pores.
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Salerno
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy; Department of Bioengineering and Robotics, University of Genova, viale Causa 13, I-16145 Genova, Italy.
authors.forename: Amirreza
authors.initials: A
authors.lastname: Shayganpour
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy; Department of Bioengineering and Robotics, University of Genova, viale Causa 13, I-16145 Genova, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Salis
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Dante
keywords: SERS; anodic porous alumina; nanopores; supported lipid bilayers; thiols