From Understanding Cellular Function to Novel Drug Discovery: The Role of Planar Patch-Clamp Array Chip Technology

Abstract

All excitable cell functions rely upon ion channels that are embedded in their plasma membrane. Perturbations of ion channel structure or function result in pathologies ranging from cardiac dysfunction to neurodegenerative disorders. Consequently, to understand the functions of excitable cells and to remedy their pathophysiology, it is important to understand the ion channel functions under various experimental conditions – including exposure to novel drug targets. Glass pipette patch-clamp is the state of the art technique to monitor the intrinsic and synaptic properties of neurons. However, this technique is labor intensive and has low data throughput. Planar patch-clamp chips, integrated into automated systems, offer high throughputs but are limited to isolated cells from suspensions, thus limiting their use in modeling physiological function. These chips are therefore not most suitable for studies involving neuronal communication. Multielectrode arrays (MEAs), in contrast, have the ability to monitor network activity by measuring local field potentials from multiple extracellular sites, but specific ion channel activity is challenging to extract from these multiplexed signals. Here we describe a novel planar patch-clamp chip technology that enables the simultaneous high-resolution electrophysiological interrogation of individual neurons at multiple sites in synaptically connected neuronal networks, thereby combining the advantages of MEA and patch-clamp techniques. Each neuron can be probed through an aperture that connects to a dedicated subterranean microfluidic channel. Neurons growing in networks are aligned to the apertures by physisorbed or chemisorbed chemical cues. In this review, we describe the design and fabrication process of these chips, approaches to chemical patterning for cell placement, and present physiological data from cultured neuronal cells.

Matrix stiffness modulates formation and activity of neuronal networks of controlled architectures

“…Indeed, microprinted neuronal networks was already achieved successfully on different surfaces such as glass [8,9], silicon substrates [23] or single-layered graphene substrates [24] but the effect of the surface rigidity on neuronal networks remained unknown. Here we show that cortical neuronal networks designed on stiff substrates maintained their spatial structures for up to 21 days in vitro without altering their spatial organization and functional activity, allowing to investigate the basic principles of the physical and functional connectivity within large neuronal networks.…”

Novel KCNQ2 channel activators discovered using fluorescence-based and automated patch-clamp-based high-throughput screening techniques

“…To reduce the false positive rate, a secondary confirmation is often required with duplicates for each compound and counter screening for the parental cells that do not express the KCNQ channels investigated [21] . A conventional patch-clamp experiment is the gold standard for studying ion channels and provides a large quantity of information as well as high resolution; however, due to intrinsic limitations, particularly due to its low throughput, conventional patchclamp is not able to satisfy the need of high-throughput drug discovery [27] . In response to the demand for high-throughput experiments, many automated patch-clamp systems have been www.chinaphar.com Yue JF et al Acta Pharmacologica Sinica npg developed throughout the last 30 years [28] .…”

‘Body-on-a-Chip’ Technology and Supporting Microfluidics

“…124 Planar patch-clamp array chips (a combination of patch clamp and MEA technology) enable the simultaneous high-resolution electrophysiological interrogation of individual neurons at multiples sites in synaptically connected neuronal networks. 125 The highresolution and high-throughput features provide the potential for utilising this technology in screening drugs with a broad range of targets and assessing responses at both the single cell and neural network levels. 123,126 In order to accurately model the nervous system, multiple models have been established, aimed at addressing varied neuronal functions.…”