Biochemical Sensors

Overview:

A biosensor is an analytical device that can convert a biological reaction into an electrical (voltage) signal. Biosensors consist of a biological element (e.g. enzyme, whole cell, etc) that is immobilized on a membrane and connected to a transducer (probe). The reaction occurs at the membrane where the substrate of interest is converted to a product that causes an electrical response. This response is measured by the transducer and then amplified, processed and displayed using a meter and PowerLab data acquisition system.

 

Method:

Potentiometric Biosensors
Potentiometric biosensors use ion selective electrodes to measure a biological reaction. A simple example is the glass pH electrode. As a biosensor it consists of an immobilized enzyme membrane surrounding the thin glass membrane of the pH probe. The biological reaction occurs at the enzymatic membrane and generates hydrogen ions (H⁺). The H⁺ ions diffuse and bind to a glass membrane, thereby generating an electrical potential that is proportional to the substrate concentration. A separate reference electrode (e.g. Ag/AgCl) is also required. Most pH meters with an analog output are suitable for use with a PowerLab data acquisition system.

Note: More information is available from the pH and Ionic Concentrations application page.

Amperometric Biosensors & Mass Sensors
Amperometric biosensors, mass sensors and associated amplifiers/meters can be used with a PowerLab data acquisition system provided that they have a suitable analog output (± 10V).

Software:

LabChart
LabChart software (for Windows and Macintosh) combines the familiar simplicity of a traditional strip chart recorder with the powerful analysis features of a digital acquisition system. LabChart software and a PowerLab data acquisition unit provide data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Acquisition and analysis capabilities can be further increased with LabChart Extensions and LabChart Modules. LabChart Modules are available as part of LabChart Pro and LabChart Extensions are free for download from the website for existing LabChart users.

GLP and 21 CFR Part 11
For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.
 

Hardware:

PowerLab Data Acquisition Systems

• PL3504 PowerLab 4/35 - 4 Channels
• PL3508 PowerLab 8/35 – 8 Channels
• PL3516 PowerLab 16/35 – 16 Channels

Signal Conditioners

ML165 pH Amp
This amplifier is a dual front-end suitable for pH, ion selective, and temperature measurements in solution recordings. It is supplied with a RTD Temperature Probe. It can be used with:

• MLA060 Redox Electrode
• MLA042 pH Electrode
• MI-405 Miniature Glass Electrode for pH
• MI-409 Miniature Reference Electrode

Transducers and Accessories

• MLA060 Redox Electrode - The combination Redox Electrode is suitable for operation from 0 to 60°C. The double junction is easily cleaned, making it suitable for biological samples.
• MLA042 pH Electrode - The combination pH Electrode operates from 0 to 60°C and for a pH of 0 to 14. The double junction is easily cleaned and therefore the electrode is suitable for biological samples, in particular those of low ionic strength.
• MI-405 Miniature Glass Electrode for pH - This miniature electrode has many applications in general purpose analyses and in microchemical studies. It requires the use of an external reference electrode such as the MI-409 Miniature Reference Electrode.
• MI-409 Miniature Reference Electrode - This electrode is designed for use with any pH or ion selective electrodes and used with the ML165 pH Amp. It has an internal Ag-AgCl internal reference electrode with KCl filling solution.

Quantitative on-line monitoring of hippocampus glucose and lactate metabolism in organotypic cultures using biosensor technology
J B Gramsbergen, G Leegsma-Vogt, K Venema, J Noraberg and J Korf, Journal of Neurochemistry, 399-408, 2003

Mixed-metal cluster chemistry. 19. Crystallographic, spectroscopic, electrochemical, spectroelectrochemical, and theoretical studies of systematically varied tetrahedral group 6-Iridium clusters
N T Lucas, J P Blitz, S Petrie, R Stranger, M G Humphrey, G A Heath and V Otieno-Alego, Journal of the American Chemical Society, 5139-5153, 2002

Impact of Porous Electrode Properties on the Electrochemical Transfer Coefficient
Soderberg J.N, Co A.C, Sirk A.H.C and Birss V.I., Journal of Physical Chemistry B, 10401-10410, 2006