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

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

GABA in the guinea-pig enteric nervous system / by Anthony Krantis

Typescript (photocopy)154 leaves, [15] leaves of plates : ill. ; 30 cm.Thesis (Ph.D.) -- University of Adelaide, Dept. of Human Physiology, 198

Surface patterning with chemisorbed chemical cues for advancing neurochip applications

We are currently developing multisite planar patch-clamp chips capable of recording high resolution electrophysiological function from individual neurons established in culture. This capability provides a unique opportunity to establish and study communication between synaptically connected neurons on-chip at the level of ion channel function. Critical to realizing this goal for mammalian cell applications are chip surface functionalization strategies that will promote attraction and adhesion of cells to on-chip interrogation features as well as facilitate in the guidance of connectivity between neurons. Here, a chemical strategy is presented that has been adapted to be compatible with standard photolithography techniques for chemical patterning of amine rich cell adhesion promoters on silicon-based surfaces. This chemisorption approach will not only enable electrophysiological studies of neuronal networks but also allow patterning of small peptides such the ones containing the RGD motif, known to induce cell adhesion via molecular recognition of integrin receptors on cell membranes and also stimulate other important biological processes.Peer reviewed: YesNRC publication: Ye

Cell placement and guidance on substrates for neurochip interfaces

Interface devices such as integrated planar patch-clamp chips are being developed to study the electrophysiological activity of neuronal networks grown in vitro. The utility of such devices will be dependent upon the ability to align neurons with interface features on the chip by controlling neuronal placement and by guiding cell connectivity. In this paper, we present a strategy to accomplish this goal. Patterned chemical modification of SiN surfaces with poly-D-lysine transferred from PDMS stamps was used to promote adhesion and guidance of cryo-preserved primary rat cortical neurons. We demonstrate that these neurons can be positioned and grown over microhole features which will ultimately serve as patch-clamp interfaces on the chip.Peer reviewed: NoNRC publication: Ye

A multiple recording patch clamp chip with integrated subterranean microfluidic channels for cultured neuronal networks

We report on a new type of patch-clamp chip that can simultaneously monitor electrophysiological activity from several individual neurons grown in simple networks. As in automated patch-clamp chips used for isolated cells in suspension, cells are interrogated using a microhole integrated into a membrane. The novelty of our chip resides in its capacity to position, culture and guide neurons into organized networks over multiple interrogation sites, thereby permitting high resolution monitoring of pre and post synaptic activity in these networks.NRC publication: Ye