Nanobiohybrids: Bioinspired Sensors
- PDF / 134,510 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 37 Downloads / 201 Views
K9.5.1
Nanobiohybrids: Bioinspired Sensors Nikolaos Chalkias1 and Emmanuel P. Giannelis2 Chemical and Biomolecular Engineering, 2Materials Science and Engineering, Cornell University, Ithaca NY, Bard Hall 214, 14853 1
ABSTRACT Nanohybrid artificial membranes made by intercalation of amphiphilic molecules into the galleries of a layered host, exhibit characteristics similar to biological membranes and they can be used as sensors. Different responses have been observed even for molecules that have similar features for example, saccharin and its sodium salt suggesting that the nanohybrid might be useful in developing an electronic nose. The dynamic range of the saccharin sensor is 20 - 300µM. In this paper we present our results on sensor fabrication and testing and discuss possible sensing mechanisms. In addition, we describe our work on immobilizing in the nanohybrid membranes Glucose Oxidase, Horseradish Peroxidase and Gramicidin and evaluating their performance. INTRODUCTION For several decades analytical chemists have been inspired from the biological sciences. One of the most important models is the cell, whose specificity and sensitivity makes it the ideal sensor. All of the communications of the cell with the outside world take place on its surface consisting of the cell lipid bilayer and integrated proteins. Inspired by the above example, the number of publications related to lipid films as sensors and biosensors is growing fast. A review article in 2001 by Trojanowicz [1] lists 122 articles using Lipid Bilayer Membranes (BLMs) in analytical applications. One of the major disadvantages is that freely suspended BLMs are mechanically fragile and unsuitable for most practical applications. However, in the last few years supported BLMs have been used on metal surfaces (solid-supported), in polymer matrixes (gel-supported) or deposited on porous membranes (filter-supported). Even though the above modifications improve the stability of BLMs, it doesn’t solve the problem and most of these have a lifetime of only hours or days. In this paper we present an alternative approach to more robust artificial membranes that can serve as versatile and fast sensors. To preserve the bilayer structure of the cell lipids, amphiphilic molecules were intercalated into the nanometer galleries of an inorganic host resulting in a nanohybrid artificial membrane with BLM-like structure. EXPERIMENTAL DETAILS Synthetic layered silicates, Somasif ME-100 (Na+-Fluoromica or FM obtained from CO-OP Chemical LTD) with a cation exchange capacity (CEC) of 120 mequiv/100g were utilized. The nanohybrid membrane was synthesized via a cation exchange reaction between the layered host and excess alkylammonium cations (1.5 times the cation exchange capacity of the host). The resulting material is abbreviated as
K9.5.2
Figure 1: SEM picture of a 2C18FM membrane. Also shown is a computer simulation of the artificial membrane showing the bilayer arrangement of the amphiphile molecules. The beads represent the hydrophilic groups and the long lines the
Data Loading...
