Multifunctional substrates of thin porous alumina for cell biosensors

Abstract

We have fabricated anodic porous alumina from thin films (100/500 nm) of aluminium deposited on technological substrates of silicon/glass, and investigated the feasibility of this material as a surface for the development of analytical biosensors aiming to assess the status of living cells. To this goal, porous alumina surfaces with fixed pitch and variable pore size were analyzed for various functionalities. Gold coated (about 25 nm) alumina revealed surface enhanced Raman scattering increasing with the decrease in wall thickness, with factor up to values of approximately 10(4) with respect to the flat gold surface. Bare porous alumina was employed for micro-patterning and observation via fluorescence images of dye molecules, which demonstrated the surface capability for a drug-loading device. NIH-3T3 fibroblast cells were cultured in vitro and examined after 2 days since seeding, and no significant (P > 0.05) differences in their proliferation were observed on porous and non-porous materials. The effect on cell cultures of pore size in the range of 50-130 nm--with pore pitch of about 250 nm--showed no significant differences in cell viability and similar levels in all cases as on a control substrate. Future work will address combination of all above capabilities into a single device.

Mesoporous alumina as a biomaterial for biomedical applications

“…In contrast, cell functionality was fostered on membranes with small pore diameters of around 50 nm [21]. These results agree with the results obtained using 50-150 nm PAA and NIH-3T3 fibroblast cells [22], 20-200 nm pore size alumina and human osteoblast-like MG63 cells [23], and 75-300 nm pore size alumina and NIH 3T3 cells [24].…”

Thin nanoporous alumina-based SERS platform for single cell sensing

“…The limited thickness of the films prevented us from performing a two-step anodization process which yields hexagonally ordered arrays of pores in thick APA [34,37] grown from Al foils. However, thin APA surfaces with irregular pore arrangement were also demonstrated to provide SERS effect [50]. The reduced thickness is an advantage in the perspective of developing a device, because it allows integration with standard lithographic methods.…”

“…In this respect, assessing the influence of the A c c e p t e d M a n u s c r i p t surface porosity of APA on cell adhesion would provide valuable information. In addition, metal coated thick APA can be used as an efficient large-area SERS substrate [49][50][51]. In a few cases APA was already used for SERS applications, but mainly as a mold to fabricate plasmonic nanostructures, for example gold (Au) NPs arrays.…”

Characterization of nanopores arrangement of anodic alumina layers synthesized on low-(AA1050) and high-purity aluminum by two-step anodizing in sulfuric acid with addition of ethylene glycol at low temperature

“…One of the most commonly used approach of manufacture nanomaterials such as nanodots [1,2], nanowires [3][4][5][6][7] and nanotubes [8,9] of metal, oxide or semiconductor [10,11] is template assisted method with the use of anodic aluminium oxide (AAO) as a template. In this aspect the arrangement of nanopores of the nanoporous aluminium oxide template is very important parameter, because it determines the arrangement of the fabricated nanomaterials [12].…”