Automated patch clamp

Automated patch clamping was developed in the late 2000s and early 2010s to replace the manual method of patch clamping used to record the electrical activity in individual cells. This work was done to help improve the speed and yield of electrophysiology experiments. Automation systems have been developed for both in vivo and in vitro experiments.

Manual vs. Automated

Manual Patch Clamp

The traditional manual methods developed by Erwin Neher and Bert Sakmann require a skilled technician to lower the recording pipette into the brain and apply the appropriate pressure to create an electrical seal with the cell called a "giga seal". The technician must provide a high initial pressure with their mouth while simultaneously lowering the pipette into the brain with a micromanipulator. After the pipette reaches the desired region in the brain, the pressure is reduced and the pipette is slowly lowered until the tip makes contact with a cell. The operator can detect contact by watching how the resistance of the pipette changes with time (see figure). The closer to a cell the tip of the pipette gets, the higher the pipette resistance. Once contact is made, the technician then applies a small amount of suction or pressure to create the desired patch clamp configuration such as whole cell, inside out, or outside out (see patch clamp). This process can require 3-12 months to learn and is considered an art form even today.

Automated Patch Clamp

- Introduction

in-vivo automation
in culture automation
in suspension automation

Automation Systems

pipette position control
pressure control
electrical control
culture/profusion/chemical control

In vivo

The automated methods developed recently basically replace the pressure and position control of the technician with a sophisticated computer program that can change the pressure, move the pipette, and monitor the electrical signals to perform the same basic steps. A high precision pneumatic pressure control system replaces the pressure and vacuum originally provided by the mouth of the technician. The position control is performed by a computer that sends position signals to an electronic manipulator previously operated by the technician. The electrical signal is also monitored by the computer where it calculates the change in the electrical signal as the pipette makes contact with the cell. All of these steps are performed in the same logical sequence as manual patch clamping but without the required presence of a skilled technician. This reduces the amount of training and expense required to gather patch clamp recordings. ^[1]

The importance of simultaneous recording is shown by 4 simultaneous recordings has been shown in a dish of cells using manual patch clamping and 16+ have been simultaneously recorded using an automated system ^[2]. However, when patch clamping is attempted in a live mouse brain rather than in a culture dish where the environmental conditions are much different, the success rate drops. Only 2 simultaneous recordings had been obtained in a live mouse brain as of 2011 using manual methods.

Benefits of in vivo patch clamping over slice, culture, or suspension.
Benefits of slice, culture, or suspension over in vivo
current state of the art

In Culture

microchip automated patch clamp of cells in culture ^[3]
scanning patch-clamp technique ^[4]

In Suspension

Electrical currents in cells that are suspended in a liquid are obviously different than studying currents in a cellular network like neurons. Because the cells are dissociated, the ionic currents in that single cell can be measured in detail. This allows the investigator to study ion channel behavior in a more controlled environment without input currents from the network. This is particularly useful in drug screening studies where the target is a specific protein. ^[5]

- History of microchip systems ^[6]

patch different cell types typically expressing human ion channel genes
patch clamp microchips emerged in the 1900s ^[7]
glass chips ^[8]

- Microchip systems (Port-a-Patch) ^[2] automated ion channel drug screening using neurons in suspension. - QPatch ^[9]

16-48 patches in parallel
automated drug profusion
automated cell suspension culture
used by many pharmeceutical companies
not in-vivo network
not physiological conditions (flow, chemical concentrations, etc.)
not generally useful for neurons

- PatchXpress

- IonWorks

- SealChip ^[10]

References

^ Kodandaramaiah, Suhasa B; Franzesi, Giovanni Talei; Chow, Brian Y; Boyden, Edward S; Forest, Craig R (2012). "Automated whole-cell patch-clamp electrophysiology of neurons in vivo". Nature Methods. 9 (6): 585–587. doi:10.1038/nmeth.1993. ISSN 1548-7091. PMC 3427788. PMID 22561988.
^ ^a ^b Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1002/smll.200600083, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1002/smll.200600083 instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/s10544-010-9452-z, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/s10544-010-9452-z instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0006-3495(02)75330-7, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S0006-3495(02)75330-7 instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1038/nrd2552, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1038/nrd2552 instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S1359-6446(04)03064-8, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S1359-6446(04)03064-8 instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/978-1-60327-258-2_10, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/978-1-60327-258-2_10 instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1039/B901025D, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1039/B901025D instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1089/154065803770381048, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1089/154065803770381048 instead.
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1089/154065803770381039, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1089/154065803770381039 instead.

External links

[KodandaramaiahFranzesi2012-1] Kodandaramaiah, Suhasa B; Franzesi, Giovanni Talei; Chow, Brian Y; Boyden, Edward S; Forest, Craig R (2012). "Automated whole-cell patch-clamp electrophysiology of neurons in vivo". Nature Methods. 9 (6): 585–587. doi:10.1038/nmeth.1993. ISSN 1548-7091. PMC 3427788. PMID 22561988.

[Brüggemann2006-2] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1002/smll.200600083, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1002/smll.200600083 instead.

[martinez2010-3] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/s10544-010-9452-z, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/s10544-010-9452-z instead.

[gorelik2002-4] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0006-3495(02)75330-7, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S0006-3495(02)75330-7 instead.

[5] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1038/nrd2552, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1038/nrd2552 instead.

[Wood2004-6] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S1359-6446(04)03064-8, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S1359-6446(04)03064-8 instead.

[jonse2009-7] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/978-1-60327-258-2_10, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/978-1-60327-258-2_10 instead.

[8] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1039/B901025D, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1039/B901025D instead.

[kuchinsky2003-9] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1089/154065803770381048, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1089/154065803770381048 instead.

[Xu2004-10] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1089/154065803770381039, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1089/154065803770381039 instead.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]