The IonWorks® Quattro System's high throughput and low operating costs make it well suited for the primary screening of directed libraries, compound profiling, and safety assessment assays.
*IonWorks Quattro System is available as a refurbished system only. More info >
Automated patch clamp systems offer considerably higher throughput than conventional patch clamping, but there is still a pressing need to match the throughput of surrogate assays while simultaneously driving down the per compound assay costs. To achieve such a goal, Molecular Devices developed the IonWorks Quattro System with Population Patch Clamp™ (PPC) technology.
PPC technology provides improved data quality and brings stability and consistency that is required for robust single-point screening and pharmacological assays for ion channel targets. Well-to-well variability is so consistent in IonWorks Quattro System experiments that highly robust Z'-Factors can be obtained, and are similar to Z'-Factor values obtained on the FLIPR® System.
The throughput of the IonWorks Quattro System is ideal for generating comprehensive pharmacological determinations for dozens of compounds in a single experiment. Using 96- or 384-well compound plates, a wide variety of dose-response experiments can be designed, including any number of titrations from 3-12 concentrations-with or without replicates. The figure above illustrates the tighter distribution of data from a KV1.3 pharmacology experiment using the IonWorks Quattro System. Each data point is comprised of 4 replicates per concentration.
- Parallel data acquisition on a 384-well PatchPlate utilizing 48 discrete amplifiers combined with a 12- or 48- channel pipettor head to achieve a throughput of over 2,300 data points per day
- Automated experimental runs allow the collection of 384 data points without user intervention
- IonWorks PatchPlate Consumable delivers a direct electrophysiological assay at the lowest per well data point cost
- Population Patch Clamp™ (PPC) (patent pending) is an enabling technology which reduces well-to-well variability to deliver consistent, high quality results
- Supports single hole (SH) recording to obtain data from individual cells during ion channel assay optimization and for clonal selection during cell line generation
- Rapid analysis of ionic currents for ease of integration into your data analysis workflow
- Wash station for fixed pipettor tips to eliminate compound carryover
Compatibility with the Original PatchPlate Consumable
The IonWorks Quattro System is compatible with both the original single-hole PatchPlate and the PatchPlate™ PPC Consumables. A new amplifier was designed for the IonWorks Quattro System allowing the user to switch between the two PatchPlate choices. The user simply selects the type of PatchPlate while configuring the experimental protocol in the software prior to the start of each experiment.
Four-fold Increased Throughput Over IonWorks HT
Population Patch Clamp technology permits a four-fold increase in throughput over the IonWorks HT System-already the highest throughput automated electrophysiological system on the market. The IonWorks Quattro System is capable of producing over 2,300 data points in 6 hours of operation.
Reduction in Cost Per Data Point
Because of the increased throughput of the IonWorks Quattro System, the cost per compound tested is significantly reduced by more than 50% relative to the IonWorks HT System.
Biological variability (i.e., cell health, cell size, and channel expression levels) is the major contributing factor for reduced success rates in planar patch clamp systems. To compensate, the IonWorks® HT system was initially designed to increase the likelihood of obtaining at least one successful recording for every compound by assaying compounds in quadruplicates. Thus the probability of obtaining at least one recording for every compound using a cell line with 70% success rate is 99.2%; but at the expense of lower throughput. A four-fold increase in throughput could be immediately realized in the IonWorks HT system by eliminating the quadruplicates. To achieve this objective, Molecular Devices developed Population Patch Clamp™ (PPC) technology1,2, a revolutionary approach that records averaged ionic currents from a population of up to 64 cells expressing a recombinant voltage-gated ion channel. Cells are plated into a 384-well PatchPlate™ PPC substrate in which each well containing 64 recording sites as depicted below showing 5 of the 64 holes.
Consistency and Data Quality: PPC provides better data consistency and data quality because ionic currents are measured from a population of cells. The average current measured during experiments on the IonWorks® Quattro system is highly consistent from one well to the next. The measured currents on the IonWorks Quattro system have significantly reduced coefficient of variation values. The %CV for Kv1.3 currents is 8% versus 34% for the IonWorks Quattro and IonWorks HT systems, respectively; for Nav1.5 currents, 18% versus 44%, respectively; and for hERG currents, 28% versus 50%, respectively. Raw data traces from PPC recordings are shown below.
Success rates are so high (above 95%) that it is not necessary to apply test compounds redundantly to four wells, thereby enabling an immediate four-fold throughput improvement over the first-generation IonWorks HT system.
Voltage-gated ion channels
Many voltage-gated ion channels (VGIC) including Na+, K+, Cl-, and Ca2+ channels have been measured on IonWorks systems. The same VGIC targets measured on the IonWorks HT and Quattro systems can be measured on the IonWorks® Barracuda Plus System.
Directed library screening
The introduction of the Population Patch Clamp (PPC) Technique allowed the screening of large directed libraries in the 10's-100's of thousands of compounds against ion channel targets. Examples of these screens can be found in peer-reviewed publications.
The IonWorks® family of instruments has been shown to be an excellent way of identifying and optimizing cell lines for use with IonWorks systems and other electrophysiological assays.
Ion channels targets are implicated in many diseases. Once researchers determine that a particular ion channel is involved in a particular disease state, a screening assay can be established against which large numbers of compounds can be screened to identify "hits" or "leads" that could ultimately become drug candidates.
After "hits" or "leads" have been identified, drug discovery researchers optimize their chemical structure in order to get the best possible drug candidates-the compounds that are most likely to have the desired effect on ion channels with the fewest possible side effects.
A critical part of lead optimization involves early safety assessments, such as hERG testing, in order to eliminate any compounds with potential safety concerns as early as possible. This allows researchers to focus their resources on the most promising drug candidates to streamline the drug discovery process. Safety assessment assays including hERG, HCN, KCNQ, and Nav 1.5 channels have been published.
The software is designed with the screening environment in mind. Protocols are run such that there is no user intervention required during the course of an experimental run. The user simply adds the PatchPlate™ Consumable and cells at the beginning of each run. The software executes the experimental protocol and cleaning procedures in preparation for the next run. It can also be run in iterative mode where the voltage protocol can be changed during assay development. The software controls the pipettor and electronic head wash stations to allow for adjustable amounts of cleaning or the use of two solutions during the pipettor head wash.
- Primary Screen of a Directed Compound Library Against Nav1.5 Channels Using Population Patch Clamp Technology
- Parallel Resistance Calculator for IonWorks Quattro: Seal Resistance Distributions and the Transfer of Assays From Single-Hole to Population Patchplate Substrates
- Population Patch Clamp Improves Data Consistency and Success Rates in the Measurement of Ionic Currents
Finkel A, Wittel A, Yang N, Handran S, Hughes J, Costantin J.
J Biomol Screen. 2006 Aug;11(5):488-96. Epub 2006 Jun 7.
- Population Patch Clamp Electrophysiology: A Breakthrough Technology for Ion Channel Screening
Dale TJ, Townsend C, Hollands EC, Trezise DJ.
Mol Biosyst. 2007 Oct;3(10):714-22. Epub 2007 Jun 15.