Signaling Studies of Protein-Peptide Binding on Microelectrode Arrays

Abstract

Electrochemical methods provide unique opportunities for non-traditional synthesis and analytical studies. Using electrochemistry, we are able to synthesize addressable molecular surfaces on microelectrode arrays and then utilize the surface to probe interactions between receptors and their biological targets. To this end, the electrodes on the surface are individually addressable. They can be used as synthetic tools to generate reagents and catalysts and in so doing trigger chemical reactions on the surface of the array above the electrodes. This allows us to synthesize and/or place molecules on the arrays directly above specific individually addressable electrode in the arrays that can then be used to study the binding behavior of those molecules. While this work has shown to be successful, significant challenges still remain. While the binding signals can be observed for peptide – protein interactions on the functionalized surface of the array, the signals obtained are amplified due to avidity effects. This amplification creates difficulties when it comes to comparing the data obtained on an array to the to existing binding data in the literature. At times, it makes it difficult to quantify a binding event at all since the amplification can shift a binding curve to a point where part of it cannot be observed. Therefore, it is extremely important to develop methods by which we can calibrate the signals produced and recorded on the microelectrode arrays and optimize those signals in a reproducible way. For this reason, we have been exploring how the nature of the functionalized array surface influences the binding signal. Our work is exploring how the relative concentration of molecules on the surface of the array can be used tune the value of the binding constant measured for an interaction on a microelectrode array, how the use and length of a linker between the molecule being studied and the array can be used to optimize the intensity of the signal, and how adjusting the hydrophilicity of the functionalized surface can be used to increase the signal to noise associated with the experiments. This work will be discussed along with ways to trouble shoot experiments in connection with surface versus solution issues that can arise.Reference: Nai-Hua Yeh, Yu Zhu, and Kevin D. Moeller*, ChemElectroChem 2019, 6, pp 4134-4143