Nanotubes and nanoparticles based 3D scaffolds for the construction of high performance Biosensors
- PDF / 288,243 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 49 Downloads / 215 Views
Nanotubes and nanoparticles based 3D scaffolds for the construction of high performance Biosensors Meenakshi Singh1, Michael Holzinger1, Maryam Tabrizian2, and Serge Cosnier1 1
Université Joseph Fourier, Département de Chimie Moléculaire UMR-5250, ICMG FR-2607, CNRS, Grenoble, France. 2 McGill University, Biomat'X Research Laboratories, Dept. of Biomedical Engineering and Faculty of Dentistry, Montréal, Canada. ABSTRACT 3D scaffolds with different pore sizes, using single-walled carbon nanotubes (SWCNTs) and nanoparticles of different size were constructed. Biotinylated glucose oxidase (GOX-B) and anti-cholera toxin (anti-CT) were immobilized onto the one and two level nanoscaffolds, functionalized with pyrene-β-cyclodextrin for the construction of glucose based enzyme sensors and immunosensors, respectively. For enzyme sensors, highest current density and sensitivity (41.72 µA cm-2, 3 mA M-1 cm-2) were obtained with two level scaffolds made with 100 nm nanoparticles. In contrast to this, for immunosensors, highest current density and sensitivity (11.71 µA cm-2, 116.2 µA M-1 cm-2) were obtained with two level scaffolds made with 500 nm nanoparticles, indicating that the pore sizes can be adjusted using different size of nanoparticles for the respective applications. INTRODUCTION In the past years, several approaches have been reported to realize electrochemical detection of biological targets using single-walled carbon nanotubes (SWCNTs) [1]. Some attempts to design 3D layer-by-layer structures to improve the sensor sensitivity by increasing the density of the immobilized bioreceptors, were limited to the fabrication of enzyme sensors. Indeed, the enzyme sensors are used for the determination of small analyte such as glucose or catechol that can diffuse easily into multilayered enzyme 3D structures [2, 3]. In case of immunosensors, in addition to the bioreceptor unit (antigen) and analyte (antibody), an additional secondary antibody labelled with a redox enzyme has to be immobilized, which are several hundred nanometers in size. Therefore, optimal diffusion of all these biological receptors and the analyte remains a challenge for immunosensing applications. In this work, with the size of nanoparticles, the pore size of the scaffolds was optimized to immobilize a maximum amount of bioreceptors, and even enzymatic markers attached to large secondary antibodies. EXPERIMENTAL DETAILS The different 3D nanotubes/nanoparticles scaffolds were constructed on the platinum electrodes (Φ = 2 mm). Nanotubes were purchased from Unidym, Sunnyvale, CA. Standard Carboxyl-Adembeads 0211 (100 nm) and masterbeads Carboxylic Acid 0215 (500 nm) were
97
purchased from Ademtech. Magnetic microparticles (Dynabeads M-270 carboxylic acid (2.4 µm)) were purchased from Invitrogen. For one and two level scaffolds, the first layer of nanotubes (20 µL, 0.1mg/mL in NMethylpyrrolidine, NMP) was deposited by classical drop casting method [4]. Supplement levels were constructed by repeatedly deposition of nanoparticles (NPs) / microparticles (µPs)
Data Loading...
