Gigaohm Seal Research Articles

Reducing agents facilitate membrane patch seal integrity and longevity

ABSTRACT The patch clamp method is a widely applied electrophysiological technique used to understand ion channel activity and cellular excitation. The formation of a high resistance giga-ohm seal is required to obtain high-quality recordings but can be challenging due to variables including operator experience and cell preparation. Therefore, the identification of methods to promote the formation and longevity of giga-ohm seals may be beneficial. In this report, we describe our observation that the application of reducing agents (DTT and TCEP) to the external bath solution during whole-cell patch clamp recordings of heterologous cells (HEK and LM) and cultured primary cells (DRG neurons) enhanced the success of giga-ohm seal formation. Reducing agents also maintained the integrity of the seal for longer periods of time at strong hyperpolarizing voltages, whereas an oxidizing agent (H2O2) appeared to have the opposite effect. In summary, we report a useful tool to improve the quality of patch clamp recordings that may be helpful in certain experimental contexts.

Leak current, even with gigaohm seals, can cause misinterpretation of stem cell-derived cardiomyocyte action potential recordings.

Human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have become an essential tool to study arrhythmia mechanisms. Much of the foundational work on these cells, as well as the computational models built from the resultant data, has overlooked the contribution of seal-leak current on the immature and heterogeneous phenotype that has come to define these cells. The aim of this study is to understand the effect of seal-leak current on recordings of action potential (AP) morphology. Action potentials were recorded in human iPSC-CMs using patch clamp and simulated using previously published mathematical models. Our in silico and in vitro studies demonstrate how seal-leak current depolarizes APs, substantially affecting their morphology, even with seal resistances (Rseal) above 1 GΩ. We show that compensation of this leak current is difficult due to challenges with obtaining accurate measures of Rseal during an experiment. Using simulation, we show that Rseal measures (i) change during an experiment, invalidating the use of pre-rupture values, and (ii) are polluted by the presence of transmembrane currents at every voltage. Finally, we posit that the background sodium current in baseline iPSC-CM models imitates the effects of seal-leak current and is increased to a level that masks the effects of seal-leak current on iPSC-CMs. Based on these findings, we make recommendations to improve iPSC-CM AP data acquisition, interpretation, and model-building. Taking these recommendations into account will improve our understanding of iPSC-CM physiology and the descriptive ability of models built from such data.

The suitability of high throughput automated patch clamp for physiological applications.

Although automated patch clamp (APC) devices have been around for many years and have become an integral part of many aspects of drug discovery, high throughput instruments with gigaohm seal data quality are relatively new. Experiments where a large number of compounds are screened against ion channels are ideally suited to high throughput APC, particularly when the amount of compound available is low. Here we evaluate different APC approaches using a variety of ion channels and screening settings. We have performed a screen of 1920 compounds on GluN1/GluN2A NMDA receptors for negative allosteric modulation using both the SyncroPatch 384 and FLIPR. Additionally, we tested the effect of 36 arthropod venoms on NaV 1.9 using a single 384-well plate on the SyncroPatch 384. As an example for mutant screening, a range of acid-sensing ion channel variants were tested and the success rate increased through fluorescence-activated cell sorting (FACS) prior to APC experiments. Gigaohm seal data quality makes the 384-format accessible to recording of primary and stem cell-derived cells on the SyncroPatch 384. We show recordings in voltage and current clamp modes of stem cell-derived cardiomyocytes. In addition, the option of intracellular solution exchange enabled investigations into the effects of intracellular Ca2+ and cAMP on TRPC5 and HCN2 currents, respectively. Together, these data highlight the broad applicability and versatility of APC platforms and also outlines some limitations of the approach. KEY POINTS: High throughput automated patch clamp (APC) can be used for a variety of applications involving ion channels. Lower false positive rates were achieved using automated patch clamp versus a fluorometric imaging plate reader (FLIPR) in a high throughput compound screen against NMDA receptors. Genetic variants and mutations can be screened on a single 384-well plate to reduce variability of experimental parameters. Intracellular solution can be perfused to investigate effects of ions and second messenger systems without the need for excised patches. Primary cells and stem cell-derived cells can be used on high throughput APC with reasonable success rates for cell capture, voltage clamp measurements and action potential recordings in current clamp mode.

The residence of synaptically released dopamine on D2 autoreceptors.

SUMMARYNeuromodulation mediated by synaptically released endogenous transmitters acting in G-protein-coupled receptors (GPCRs) is slow primarily because of multistep downstream signaling. What is less well understood is the spatial and temporal kinetics of transmitter and receptor interaction. The present work uses the combination of the dopamine sensor, dLight, to detect the spatial release and diffusion of dopamine and a caged form of a D2-dopamine receptor antagonist, CyHQ-sulpiride, to rapidly block the D2 autoreceptors. Photoactivation of the CyHQ-sulpiride blocks receptors in milliseconds such that the time course of dopamine/receptor interaction is mapped onto the downstream signaling. The results show that highly localized release, but not dopamine diffusion, defines the time course of the functional interaction between dopamine and D2 autoreceptors, which determines downstream inhibition.

Recording Electrical Currents across the Plasma Membrane of Mammalian Sperm Cells.

Recording of the electrical activity from one of the smallest cells of a mammalian organism- a sperm cell- has been a challenging task for electrophysiologists for many decades. The method known as "spermatozoan patch clamp" was introduced in 2006. It has enabled the direct recording of ion channel activity in whole-cell and cell-attached configurations and has been instrumental in describing sperm cell physiology and the molecular identity of various calcium, potassium, sodium, chloride, and proton ion channels. However, recording from single spermatozoa requires advanced skills and training in electrophysiology. This detailed protocol summarizes the step-by-step procedure and highlights several 'tricks-of-the-trade' in order to make it available to anyone who wishes to explore the fascinating physiology of the sperm cell. Specifically, the protocol describes recording from human and murine sperm cells but can be adapted to essentially any mammalian sperm cell of any species. The protocol covers important details of the application of this technique, such as isolation of sperm cells, selection of reagents and equipment, immobilization of the highly motile cells, formation of the tight (Gigaohm) seal between a recording electrode and the plasma membrane of the sperm cells, transition into the whole-spermatozoan mode (also known as break-in), and exemplary recordings of the sperm cell calcium ion channel, CatSper, from six mammalian species. The advantages and limitations of the sperm patch clamp method, as well as the most critical steps, are discussed.

A stepwise approach to resolving small ionic currents in vascular tissue.

Arterial membrane potential (Vm) is set by an active interplay among ion channels whose principal function is to set contractility through the gating of voltage-operated Ca2+ channels. To garner an understanding of this electrical parameter, the activity of each channel must be established under near-physiological conditions, a significant challenge given their small magnitude. The inward rectifying K+ (KIR) channel is illustrative of the problem, as its outward "physiological" component is almost undetectable. This study describes a stepwise approach to dissect small ionic currents at physiological Vm using endothelial and smooth muscle cells freshly isolated from rat cerebral arteries. We highlight three critical steps, beginning with the voltage clamping of vascular cells bathed in physiological solutions while maintaining a giga-ohm seal. KIR channels are then inhibited (micromolar Ba2+) so that a difference current can be created, once Ba2+ traces are corrected for the changing seal resistance and subtle instrument drift, pulling the reversal potential rightward. The latter is a new procedure and entails the alignment of whole cell current traces at a voltage where KIR is silent and other channels exhibit limited activity. We subsequently introduced corrected and uncorrected currents into computer models of the arterial wall to show how these subtle adjustments markedly impact the importance of KIR in Vm and arterial tone regulation. We argue that this refined approach can be used on an array of vascular ion channels to build a complete picture of how they dynamically interact to set arterial tone in key organs like the brain.NEW & NOTEWORTHY This work describes a stepwise approach to resolve small ionic currents involved in controlling Vm in resistance arteries. Using this new methodology, we particularly resolved the outward component of the KIR current in native vascular cells, voltage clamped in near-physiological conditions. This novel approach can be applied to any other vascular currents and used to better interpret how vascular ion channels cooperate to control arterial tone.

Abstract P199: Gene Variants in Human Renal Proximal Tubule Alpha ENaC are Associated With Inverse Salt Sensitivity of Blood Pressure

The amiloride-sensitive epithelial sodium channel (ENaC) localizes to the apical membrane of epithelial cells in distal nephron, playing an important role in regulating whole-body Na + homeostasis and blood pressure. We were the first to describe the presence of αENaC in human renal proximal tubule cells (hRPTC). Gene variants in αENaC have been shown to be associated with salt sensitivity of blood pressure (SS) . We also verified that the specific gene variant rs4764586 was significantly associated with SS (χ 2 =9.67, P=0.046). In our salt sensitivity clinical study, 11% participants (N=27/240) had a paradoxical increase in blood pressure (BP) (≥7-mm Hg) on a low NaCl diet, defined as inverse salt sensitive ( ISS ) as compared to salt resistant ( SR , 72%) and salt sensitive ( SS , 17%). The incidence of the minor allele αENaC rs4764586 in the ISS group was 2-fold of that in SR or SS ( ISS , 14.8%; SR , 7.0%; SS , 7.1%). Expression of αENaC protein in urine derived hRPTCs was significantly lower in ISS than in SR ( ISS , 0.55±0.01, n=3; SR, 0.97±0.12, n=3; SS, 0.87±0.12, n=3; one-way ANOVA, ISS vs SR p<0.05), with the lowest in the homozygous variants (HV) of rs4764586 and highest in wild type. The heterozygous variant containing hRPTCs had an intermediate expression of αENaC (WT, 0.94±0.11, n=4; Heterozygous, 0.72±0.11, n=4; HV, 0.53, n=1). ENaC-like channels were demonstrated in hRPTCs using single-channel patch-clamp electrophysiology with a conductance of 10.5±0.7 pS and E rev 39.2±5.5 mV vs 10.3±0.8 pS in SR and ISS lines, respectively. However, in ISS baseline ENaC-like channel activity was too low to be recorded without trypsin in the pipette (Po = open probability), unlike SR . In contrast, ISS cells demonstrated a higher Po than SR cells in response to trypsin both immediately and after 4 minutes of activation, even though the number of channels recorded at 4 min after GigaOhm seal formation was lower in the ISS line compared to SR line (4.7±1.7 vs 1.75±0.5, p=0.042 in SR vs ISS lines). These results suggest that ISS phenotype may be related to impaired ENaC activity in the renal proximal tubule. The long-term physiologic consequences of the ISS phenotype remain to be determined

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method.

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.

Preparation of Acute Brain Slices Using an Optimized <em>N</em>-Methyl-D-glucamine Protective Recovery Method

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.

Assessing Antibiotic Permeability of Gram-Negative Bacteria via Nanofluidics

While antibiotic resistance is increasing rapidly, drug discovery has proven to be extremely difficult. Antibiotic resistance transforms some bacterial infections into deadly medical conditions. A significant challenge in antibiotic discovery is designing potent molecules that enter Gram-negative bacteria and also avoid active efflux mechanisms. Critical analysis in rational drug design has been hindered by the lack of effective analytical tools to analyze the bacterial membrane permeability of small molecules. We design, fabricate, and characterize the nanofluidic device that actively loads more than 200 single bacterial cells in a nanochannel array. We demonstrate a gigaohm seal between the nanochannel walls and the loaded bacteria, restricting small molecule transport to only occur through the bacterial cell envelope. Quantitation of clindamycin translocation through wild-type and efflux-deficient (ΔtolC) Escherichia coli strains via nanofluidic-interfaced liquid chromatography mass spectrometry shows higher levels of translocation for wild-type E. coli than for an efflux-deficient strain. We believe that the assessment of compound permeability in Gram-negative bacteria via the nanofluidic analysis platform will be an impactful tool for compound permeation and efflux studies in bacteria to assist rational antibiotic design.

Biomimetic surface patterning for long-term transmembrane access

Here we present a planar patch clamp chip based on biomimetic cell membrane fusion. This architecture uses nanometer length-scale surface patterning to replicate the structure and function of membrane proteins, creating a gigaohm seal between the cell and a planar electrode array. The seal is generated passively during cell spreading, without the application of a vacuum to the cell surface. This interface can enable cell-attached and whole-cell recordings that are stable to 72 hours, and generates no visible damage to the cell. The electrodes can be very small (<5 μm) and closely packed, offering a high density platform for cellular measurement.

In praise of single channel kinetics.

It is more than 30 years since the advent of the gigaohm seal patch clamp technique, which enabled routine recordings of currents generated by the activity of a single ion channel molecule in its native environment. The muscle nicotinic acetylcholine (ACh) receptor (nAChR) is one of the best ligand-

Combining Fluorescence Microscopy on Freestanding Lipid Bilayers with Electrical Measurements

The structure, precise operation mechanism and dynamics of ion channels have not yet been elucidated because linking the structure and structure changes to function has remained challenging. We are developing new methods that allow the structure of membrane proteins to be studied in a controlled, native-like environment by simultaneously probing their structure and function. We report a second-generation membrane interferometer (Ganesan et al., Proc. Natl. Acad. Sci. 106, 2008) in which electrophysiology measurements can be performed simultaneously with high-resolution fluorescence microscopy imaging. In the membrane interferometer, a freestanding bilayer is formed over a micropore that is positioned approximately 400 nanometer above a reflective mirror. The mirror allows the use of Fluorescence Interference Contrast microscopy (FLIC) and Variable Incidence Angle-FLIC (VIA-FLIC), two surface characterization techniques that precisely locate the height of fluorescent objects relative to the silicon surface with nm resolution. The second-generation design provides electrical access on both sides and is meant to create a more planar bilayer than the earlier design. Electrophysiology measurements revealed formation of freestanding bilayers with giga-Ohm seals over the micropores that are stable for over 24 hrs. As an initial test we incorporated alpha-hemolysin channels into the bilayers and measured their activity using electrophysiology, while simultaneously imaging the lipid bilayer by FLIC to analyze its curvature. Progress on the incorporation of other fluorescently labeled ion channels will be described.

Mechanosensitivity of TRPC6 Ion Channel Reconstituted in the Liposomes

The transient receptor potential ion channel family is a diverse group of channels gated by various physical and chemical stimuli. One of the members, TRPC6, is a calcium permeable cation channel located in the ventricular cardiomyocytes. TRPC6 has been reported to be activated by mechanical force, however it is still unclear if TRPC6 is activated directly by membrane tension from the lipid bilayer or whether activation requires additional membrane components including cytoskeleton and/or extracellular matrix for its activation. Thus, it is important to elucidate the gating mechanism of TRPC6.In this study, we purified TRPC6 protein and investigated the mechanosensitivity of TRPC6 reconstituted into the liposomes using the patch clamp technique. We have transfected C-GFP TRPC6 construct into HEK293 cells and demonstrated that the channel is localised in the plasma membrane. Purification were performed using immobilized metal-affinity chromatography. To assess the integrity of the TRPC6 protein, the elution fraction was analysed by fluorescence sized exclusion chromatography (FSEC) and SDS/PAGE gel. GFP fluorescence peak using FSEC showed that TRPC6 channel is found mostly in tetramer state. Fluorescent scan of the gels demonstrated a single fluorescent band at the correct TRPC6 - GFP size. However, Coomassie staining of the same gel revealed additional bands in the gel showing that purification needs optimisation. Using isolated protein, liposome reconstitution was carried out using DR method. We recorded TRPC6 single channel activity in liposomes by patch clamping. TRPC6 ion channel activity demonstrated outward rectification and calculated conductance was ∼44 pS. By applying negative pressure to the patch pipette, we did observe multiple channel activity. TRPC6 was spontaneously active without any negative pressure applied to the patch pipette, which suggests that the membrane tension resulting from the gigaohm seal formation was sufficient to activate the TRPC6 channels.

Establishment of the Dual Whole Cell Recording Patch Clamp Configuration for the Measurement of Gap Junction Conductance.

The development of the patch clamp technique has enabled investigators to directly measure gap junction conductance between isolated pairs of small cells with resolution to the single channel level. The dual patch clamp recording technique requires specialized equipment and the acquired skill to reliably establish gigaohm seals and the whole cell recording configuration with high efficiency. This chapter describes the equipment needed and methods required to achieve accurate measurement of macroscopic and single gap junction channel conductances. Inherent limitations with the dual whole cell recording technique and methods to correct for series access resistance errors are defined as well as basic procedures to determine the essential electrical parameters necessary to evaluate the accuracy of gap junction conductance measurements using this approach.

Planar Patch Clamp System Capable of Recording Mechanosensitive Activity of Ion Channels

Response to mechanical stimuli, which includes proper development of biological tissues and organs, is essential to the cell. Mechanosensitive ion channels are the basic elements among mechanosensing molecules and complexes. Although the traditional patch clamp technique using glass micropipettes is still widely used for electrophysiology, it is difficult to control the mechanical stimulus to ion channels in this system. Here we developed a novel patch clamp system with a planar stretchable electrode to record mechanosensitive responses of ion channels. Planar electrodes of 100 μm thickness were fabricated using silicone resin. Next, we prepared HEK293 cells transfected with the stretch-activated KCa (SAKCA) channel, which is mechanosensitive, for planar patch clamp recordings. Using our planar patch clamp system, a gigaohm seal was achieved with a maximum seal resistance of 10 GΩ. The success rate of gigaohm seal formation was 37%. Then we recorded single channel currents with a slope conductance of 285.4 pS, which is parallel to the known SAKCA current. Using scanning electron microscope, we confirmed elongation of the aperture by 37.7% when 50% stretch was applied to the planar electrode. It is expected that a controllable and sufficient stretch stimulus can be applied to the cellular membrane using our newly developed planar patch clamp system.

Mechanosensitivity of TRPC6 Ion Channels

The transient receptor potential (TRP) ion channel family is a diverse group of channels gated by various physical and chemical stimuli. One of the members, transient receptor potential canonical-6 (TRPC6), is a calcium permeable cation channel (PCa/PNa ∼ 6) located in the T-tubules of ventricular cardiomyocytes. Abnormal TRPC6 activity has been implicated in cardiac hypertrophy, a maladaptive process likely triggered by increased mechanical stress. As a result, it is important to elucidate the gating mechanism of TRPC6. In addition to activation by diacylglycerol (DAG) TRPC6 has been reported to be also activated by mechanical force, though this has not been supported by other studies. In this study, we investigated the mechanosensitivity of TRPC6 overexpressed in HEK293 cells using the patch clamp technique. Three TRPC6 constructs were utilised: N- terminal fusion GFP, C-terminal fusion GFP and non-GFP fusion TRPC6. We have successfully transfected these constructs into HEK293 cells with a 60% transfection efficiency rate using Lipofectamine® 3000 reagent. Confocal images of C-GFP TRPC6 demonstrated that the channel is localised in the plasma membrane. However, N-GFP and non-GFP TRPC6 both distributed uniformly throughout the cells suggestive of impaired trafficking. In our patch clamp experiments we recorded TRPC6 single channel activity in cell-attached and whole-cell configurations. By applying negative pressure (suction) of −50 mmHg to the patch pipette we were able to record single channel activity of TRPC6 channels. Moreover, the channels were spontaneously active without application of negative pressure to the patch pipette suggesting that the membrane tension resulting from the gigaohm seal formation was sufficient to activate TRPC6. These results demonstrate that TRPC6 expressed in the plasma membrane of HEK293 cells is mechanosensitive. Future studies will focus on purifying and incorporating the TRPC6 channel protein into liposomes to establish if TRPC6 is intrinsically mechanosensitive.

Improvements in the performance of an incubation-type planar patch clamp biosensor using a salt bridge electrode and a plastic (PMMA) substrate

Incubation-type planar patch clamp biosensors, first described in 2008, are expected to enable the realization of high-throughput neural network screening. Several technical challenges must be overcome before this technique may be implemented. First, it is difficult to achieve a sufficiently high seal resistance (a gigaohm seal), which is an important parameter for patch clamp operation. A low seal resistance produces large baseline fluctuations corresponding to the fluctuation of the solid–liquid and liquid–liquid interface potentials. Second, the sensor cell must be positioned at a micropore over a long incubation time while maintaining the cell viability. Finally, a low-cost high-performance sensor chip suitable for high-throughput screening must be developed. These problems have been resolved to some extent in the present work. A stable electrode with a salt bridge structure was developed here to reduce the baseline fluctuations. The cell positioning technology was improved by forming a novel cell trapping pattern using hot embossing on a plastic (polymethylmethacrylate (PMMA)) substrate for use in a microfluidic sensor chip. The combination of the stable electrode and the cell trapping pattern dramatically increased the device success probability from ∼2% to 60–80% using HEK293 cells as a model system. The utility of the present results was tested by characterizing rat hippocampal neuron networks. The seal resistance was found to be lower than the seal resistance obtained from the HEK293 cells. The effectiveness of the stable electrodes, however, was significantly clear and spontaneous channel currents from the neural network were successfully observed.

Highly-Efficient Gating of Solid-State Nanochannels by DNA Supersandwich Structure Containing ATP Aptamers: A Nanofluidic IMPLICATION Logic Device

Integrating biological components into artificial devices establishes an interface to understand and imitate the superior functionalities of the living systems. One challenge in developing biohybrid nanosystems mimicking the gating function of the biological ion channels is to enhance the gating efficiency of the man-made systems. Herein, we demonstrate a DNA supersandwich and ATP gated nanofluidic device that exhibits high ON-OFF ratios (up to 10(6)) and a perfect electric seal at its closed state (~GΩ). The ON-OFF ratio is distinctly higher than existing chemically modified nanofluidic gating systems. The gigaohm seal is comparable with that required in ion channel electrophysiological recording and some lipid bilayer-coated nanopore sensors. The gating function is implemented by self-assembling DNA supersandwich structures into solid-state nanochannels (open-to-closed) and their disassembly through ATP-DNA binding interactions (closed-to-open). On the basis of the reversible and all-or-none electrochemical switching properties, we further achieve the IMPLICATION logic operations within the nanofluidic structures. The present biohybrid nanofluidic device translates molecular events into electrical signals and indicates a built-in signal amplification mechanism for future nanofluidic biosensing and modular DNA computing on solid-state substrates.

Electrophysiological characterization of ion channels in beta-cells using silicon based lateral patch clamp device

Metabolic syndrome, a collection of metabolic abnormalities including diabetes and obesity, affects hundreds of millions of people, and poses a major financial burden to public healthcare around the world. There are two major types of diabetes: Type-1, which is caused by a lack of insulin production and Type-2, which results from a relative deficiency of insulin secretion. Electrical activity of various ion channels in beta (β)-cells plays an important role in the stimulus-secretion of insulin in Type-2 diabetes. Here, we utilize a silicon based lateral patch clamp device to conduct whole cell patch clamp measurements in insulin secreting rat insulinoma (INS-1) cells. High gigaohm seals were achieved between the microfabricated glass capillary apertures and INS-1 cells resulting in picoampere current recordings from various potassium and calcium ion channels. Steady state I–V plots elicited characteristic ion channel properties and longevity of the whole cell mode could be maintained for 1 h without any breakage of the gigaohm seal. Glucose dose responses were also recorded and showed proportional current responses in voltage gated potassium channels. Delivery of multiple ion channel blockers (sulfonylurea drugs) resulted in suppression of currents in potassium channels. The results showcase the capability of our device in performing whole cell measurements and pave a way for developing a cheap platform using our silicon based approach.