Light-addressable potentiometric sensors (LAPS) have great potential as a tool for functional electrochemical imaging of the attachment area of cells, providing information such as ion concentration, extracellular potentials and ion channel activity. The technique is particularly attractive for analysing cell responses of cells with planar polarisation as the cell-surface attachment area is not accessible to conventional electrophysiological measurements. The technique has the advantage that different spots on a flat, featureless electrolyte/insulator/silicon field effect structure can be addressed by scanning a focused light beam across the sample thereby exciting local photocurrents and generate an electrochemical image. However, current systems suffer either from poor resolution or slow scanning speed to monitor biological processes. In this project, we aimed to develop an electrochemical scanning setup with high spatiotemporal resolution that allows imaging of physiological processes with subcellular resolution and in real time.
The setup can be used with different ion sensitive surfaces to monitor the extracellular ionic flux and its role in cellular processes. The new instrument will lend itself to the investigation of disease mechanisms, the effects of toxicity and efficacy of drugs. In the long term, this could aid the development of organ on-a-chip devices, which can reduce the need for animal models. More specifically, we are planning to develop a zinc sensitive surfaces and use them in conjunction with the high-resolution and high-speed imaging setup to investigate the role of zinc in age related macular degeneration (AMD), the mechanism of which is still not well understood. This may lead to new treatments to prevent, forestall, or reverse the effects of the disease and elucidate zinc's role in other diseases including type 2 diabetes, pancreatic cancer, and Alzheimer disease and is therefore expected to impact the pharmaceutical industry and increase the quality of life for an ageing population.
The main objective of this project was to develop a high-speed and high-resolution LAPS setup with the capability of visualizing dynamic physiological events in a microenvironment. In particular, we were interested in real-time imaging of physiological parameters of living cells and establish protocols for studying their interactions with drugs and toxins.
