Impact of Molecular Surface Charge on Electrical Impedance Spectroscopy Biosensing
Poster Mar 08, 2015
Y. Ram, T. Yoetz-Kopelman, A. Freeman and Y. Shacham-Diamand
Electrical Impedance Spectroscopy (EIS) is a powerful tool for detection and characterization for biorecognition events at the surface. It enables to perform measurements with high sensitivity without damaging biologic samples.
Employing a redox couple as probe in impedance measurements is beneficial, since it is highly sensitive to changes in the surface charge that can either increase or decrease the resistance to electrochemical charge transfer.
The goal of this work is to use EIS for biodetection of proteins, and to gain physical understanding of the detection mechanism.
The Avidin-Biotin interaction was used for the binding of biotinylated HRP to the surface of the electrode without the need to use SAM, to modify the proteins or to add a blocking layer.
Since [Fe(CN)6]3−/[Fe(CN)6]4- were used as the redox couple, it was found advantageous to use an amide-modified form of Avidin which is less positive than the original molecule. Thus, the change in resistance is much higher.
This work shows that the charge of the analyte is much more influential than its size when using EIS in comparison to two other common techniques - Cyclic Voltammetry and ELISA. In addition, detection of biotinylated HRP was achieved for concentrations in the nanomolar range.
Analysis of Extract Drying Criteria for Oil & Grease Method 1664A/BPoster
Analysis of Extract Drying Criteria for Oil & Grease Method 1664A/BREAD MORE
Fundamentals and Comparisons for Organic Sample Extract EvaporationPoster
Sample preparation is a key step in the analysis process
Parameters for evaporation and their impact on analysis have been discussed
Improvements in matching the sample to the evaporation device characteristics can help reduce variability and improve recovery
Examples for choosing a system based on sample volume, types of analytes, sample load, and initial investment considerations
Using Elemental Analysis For Discrimination Of Pinot Noir Wines From Six Different Districts In An AvaPoster
The determination of geographical origin of wine is gaining increased interest by researchers and federal agencies around the world, partially due to increased fraud with regards to place of origin labelling. For wine, multi-elemental profiling of macro, micro, and trace elements has been proposed for determination of authenticity. Commercial wines from different wineries in 5 different neighborhoods within one AVA show characteristic elemental fingerprints. Macro, micro and trace elements as well as elemental ratios contribute to the observed separation, indicating the involvement of multiple factors and underlying mechanisms, including location and soil composition, elemental uptake by vine and rootstock, viticulture and nutrient management, water sources, and small differences in the different wineries.READ MORE