Sensing Voltage Dynamics with Differential Intensity Surface Plasmon Resonance Systems
From Applied Optics Wiki
- This project is directed at researching the capacity of surface plasmon resonance systems for label-free detection of the electrical signals that are generated by the excitable cells. Electrical signals are important in communication and control in biological systems. Therefore, accurate and reliable measurements of these signals at the cell level provide valuable in vitro models for physiological and pharmacological investigations. Unlike the popular fluorescent and micro-electrode techniques, surface plasmon resonance is a label-free, non-invasive way to measure localised signals at the cell-metal interface.
- Surface plasmon resonance (SPR) sensors are conventionally used to detect molecular interactions at the metal-dielectric interface. Additionally, they demonstrated the ability to detect the externally-applied voltage, which characterises them as electrodes with optical readout. As the project is motivated by resolving weak signals associated with dynamic processes, it aims to (i) estimate the limit of voltage detection of SPR using theoretical and experimental approaches and (ii) investigate the response time of the sensors to demonstrate the ability of the technique to resolve the transient electrical signals.
- Therefore, the physical properties of the interface were investigated using optics and electrochemical models. The theoretical results were then validated experimentally using a bespoke SPR system. The project also aimed to investigate the ability of the sensing technique to detect the dynamic bio-electrical signals at 1 KHz.
Voltage Sensing System
- In order to study the voltage sensitivity of surface plasmon resonance, an SPR-basedvoltage sensing system has been designed and tested. It consists of the opticalcon�guration and the electrochemical unit. The optical con�guration is used toexcite surface plasmons at the metal-electrolyte interface while the electrochemicalunit is used to control the potential at this interface. This chapter presents thedesign of the optical system and the investigation of the sources of instability. Theintegrated system has been tested for detecting the interfacial potential using theelectrochemical system and the optical system, simultaneously.