Automation and High‑Throughput Screening
Expert-defined terms from the Certified Specialist Programme in Cell Culture Optimization course at Greenwich School of Business and Finance. Free to read, free to share, paired with a professional course.
Automated Liquid Handling – a system that precisely transfers liquids usi… #
Related terms: Pipetting robot, dispensing module. Enables reproducible reagent addition in 96‑, 384‑, or 1536‑well plates. Example: A Hamilton STAR performs 10 µL transfers for a kinase assay. Practical application: Large‑scale drug‑screening campaigns where manual pipetting would be error‑prone. Challenges include cross‑contamination, tip‑clogging, and the need for regular calibration to maintain accuracy.
Automated Microscopy – integration of motorized stages, autofocus, and im… #
Related terms: High‑content imaging, image analysis pipeline. Used to monitor cell morphology after siRNA knock‑down. Practical application: Time‑lapse monitoring of cell proliferation across dozens of plates. Challenges involve maintaining focus across uneven plates, data storage demands, and ensuring consistent illumination.
Automated Plate Reader – an instrument that measures absorbance, fluoresc… #
Related terms: Multimode reader, spectrophotometer. Example: A BioTek Synergy H1 reads 384‑well plates for a cell‑viability assay. Practical application: Rapid readout of enzymatic reactions in high‑throughput screens. Challenges include well‑to‑well variability, edge effects, and the need for regular wavelength calibration.
Automation Workflow – the sequence of programmed steps that link liquid h… #
Related terms: Protocol scripting, process integration. A typical workflow may include cell seeding, compound addition, incubation, and plate reading. Practical application: End‑to‑end drug‑screen pipelines that run unattended overnight. Challenges are error handling, synchronization of disparate devices, and ensuring software compatibility across vendors.
Batch Processing – grouping of samples or plates for simultaneous handlin… #
Related terms: Plate pooling, run queue. Example: Processing four 384‑well plates as a single batch in a liquid‑handling robot. Practical application: Reduces set‑up time and improves consistency. Challenges include limited flexibility for plate‑specific conditions and the risk of propagating a single error across many samples.
Cell Counter – an automated device that enumerates cells using image anal… #
Related terms: Hemocytometer, image‑based cytometer. Example: A Countess II uses bright‑field imaging to count suspension cells. Practical application: Rapid determination of seeding density before plating. Challenges involve distinguishing debris from cells, handling clumped cells, and calibrating for different cell sizes.
Cell Dispensing – precise delivery of a defined number of cells into well… #
Related terms: Droplet printer, acoustic dispenser. Example: A Thermo Fisher Multidrop Combi dispenses 2 000 cells per well into a 384‑well plate. Practical application: Uniform seeding for high‑content screens. Challenges include maintaining cell viability during dispensing, preventing nozzle clogging, and achieving low coefficient of variation (CV) across wells.
Cell Line Authentication – verification that a cultured cell line matches… #
Related terms: Mycoplasma testing, identity verification. Essential before large‑scale screens to avoid misidentified cells. Practical application: Routine authentication after 10 passages. Challenges are added time, cost, and integrating authentication data into laboratory information management systems (LIMS).
Cell Line Optimization – systematic adjustment of culture conditions (med… #
Related terms: Media formulation, growth curve. Example: Testing five serum concentrations to maximize ATP signal in a viability assay. Practical application: Increasing assay window for high‑throughput screens. Challenges include combinatorial explosion of variables and the need for robust statistical analysis.
Cell Viability Assay – a test that measures the proportion of living cell… #
G., MTT, resazurin) or ATP levels. Related terms: Cytotoxicity assay, live/dead staining. Example: CellTiter‑Glo luminescence readout after 72 h drug exposure. Practical application: Primary readout in compound screening. Challenges include assay interference from colored compounds, edge effects, and signal drift over long runs.
Cell Seeding Density – the number of cells plated per well, a critical pa… #
Related terms: Confluence, plating efficiency. Example: Seeding 5 000 HeLa cells per well in a 96‑well plate for a 48‑h proliferation assay. Practical application: Optimizing density to avoid over‑confluence that masks drug effects. Challenges involve precise dispensing, accounting for cell growth rates, and adjusting for different cell lines.
Cell Tracking – computational analysis of cell movement over time using t… #
Related terms: Trajectory analysis, motility assay. Example: Using ImageJ TrackMate to follow individual fibroblasts after treatment. Practical application: Assessing migration inhibitors in a high‑content screen. Challenges include image quality, cell overlap, and processing large datasets.
CellTiter‑Glo – a luminescent assay that quantifies ATP as a proxy for vi… #
Related terms: ATP assay, luminescence readout. Used in 384‑well format for rapid viability measurement. Practical application: Primary screen of 10 000 compounds for cytotoxicity. Challenges include luminescence quenching by certain chemicals and the need for rapid plate reading to avoid signal decay.
Compound Library – a curated collection of chemical entities for screenin… #
Related terms: Chemical diversity, hit library. Example: A 50 000‑compound library spanning drug‑like space. Practical application: Source of test agents in high‑throughput screens. Challenges include solubility, stability, and ensuring consistent DMSO concentration across plates.
Control Wells – wells designated for positive, negative, or reference con… #
Related terms: Assay controls, reference standards. Example: Using 0.1 % DMSO as a negative control and a known inhibitor as a positive control. Practical application: Normalizing data and assessing assay performance. Challenges involve placement to minimize edge effects and selecting appropriate controls for each assay type.
Cross‑Contamination Prevention – strategies to avoid unintended transfer… #
Related terms: Tip washing, aerosol control. Includes using filtered tips and de‑contamination cycles. Practical application: Maintaining library integrity during automated dispensing. Challenges are increased cycle time and the need for rigorous validation of cleaning protocols.
Data Analysis Pipeline – a series of computational steps that transform r… #
Related terms: Normalization, hit selection. Example: Applying plate‑based Z‑score, then filtering by % inhibition. Practical application: Rapid identification of active compounds. Challenges include handling large data volumes, batch effects, and integrating multiple assay readouts.
Data Integration – combining heterogeneous datasets (e #
G., Imaging, luminescence, genomics) into a unified analysis framework. Related terms: Multi‑omics, data fusion. Example: Linking cell‑morphology features with viability outcomes. Practical application: Uncovering mechanistic insights from high‑content screens. Challenges involve data standardization, storage, and cross‑platform compatibility.
Data Normalization – statistical adjustment of raw assay signals to reduc… #
Related terms: Z‑score, robust scaling. Example: Normalizing each plate to its median of control wells. Practical application: Improving comparability across batches. Challenges include selecting appropriate reference points and avoiding over‑correction that masks true biological effects.
Edge Effect – systematic variation in signal intensity observed at the ou… #
Related terms: Peripheral bias, plate uniformity. Example: Higher luminescence in edge wells of a 384‑well plate. Practical application: Designing plate layouts that place controls away from edges. Challenges include mitigating with humidified incubators and using plate seals.
Equipment Calibration – routine verification and adjustment of instrument… #
Related terms: Validation, routine maintenance. Example: Calibrating a liquid‑handling robot’s pipette volume using gravimetric measurement. Practical application: Ensuring accuracy of reagent dispensing. Challenges are time‑consuming procedures and the need for skilled technicians.
Flow Cytometry – a technique that analyzes physical and fluorescent chara… #
Related terms: Fluorescence‑activated cell sorting, FACS. Used for high‑throughput phenotyping of cultured cells. Practical application: Measuring surface marker expression after CRISPR perturbation. Challenges include sample preparation, data complexity, and instrument throughput limitations.
High‑Content Screening (HCS) – a form of high‑throughput screening that c… #
Related terms: Phenotypic screening, image‑based assay. Example: Using an Opera Phenix to assess nuclear size after drug treatment. Practical application: Discovering compounds that modulate subcellular localization. Challenges involve large data volumes, image analysis algorithm development, and longer assay times.
High‑Throughput Screening (HTS) – rapid testing of thousands to millions… #
Related terms: Primary screen, hit identification. Example: A 10 000‑compound library screened for kinase inhibition in 384‑well format. Practical application: Early‑stage drug discovery. Challenges include assay miniaturization, false‑positive/negative rates, and managing large data sets.
Incubator Integration – linking plate incubators directly to robotic work… #
Related terms: Environmental control, robotic arm. Example: A Liconic automated incubator moves plates to a liquid‑handler after 24 h. Practical application: Reducing manual transfer and maintaining sterile conditions. Challenges are communication protocol compatibility and handling different plate formats.
Liquid‑Handler Tip Management – strategy for selecting, loading, and disp… #
Related terms: Disposable tips, tip rack. Using filtered tips reduces aerosol contamination. Practical application: Ensuring each dispense uses a fresh tip for critical reagents. Challenges include tip consumption cost, waste generation, and tip‑clogging with viscous liquids.
Miniaturization – scaling down assay volumes and well sizes to increase t… #
Related terms: Microplate format, nanoliter dispensing. Example: Moving from 100 µL to 5 µL wells in a 1536‑well plate. Practical application: Cost‑effective screening of expensive compounds. Challenges involve maintaining assay sensitivity, handling evaporation, and ensuring accurate dispensing at low volumes.
Multi‑Mode Reader – an instrument capable of detecting multiple signal ty… #
Related terms: Plate reader, spectrofluorometer. Example: A PerkinElmer EnVision can read both FRET and luminescence assays. Practical application: Consolidating assay types to a single device, saving space and time. Challenges include switching times between modes and calibration for each detection type.
Multiplex Assay – an assay that simultaneously measures multiple analytes… #
Related terms: Dual‑luminescence, bead‑based assay. Example: Combining ATP viability and caspase‑3 activity in one plate. Practical application: Increasing data density per sample. Challenges include assay interference, signal cross‑talk, and more complex data analysis.
Normalization Controls – internal standards used to correct for plate‑to‑… #
Related terms: Reference wells, calibrators. Example: Adding a constant concentration of a fluorescent dye to each well. Practical application: Improving comparability across runs. Challenges involve selecting a control that does not affect the biology under study.
Optical Calibration – process of verifying that detection optics (filters… #
Related terms: Wavelength verification, detector linearity. Using a fluorescence standard to set gain on a plate reader. Practical application: Ensuring consistency across instruments in multi‑site projects. Challenges include drift over time and the need for periodic re‑calibration.
Plate Layout Design – strategic arrangement of samples, controls, and rep… #
Related terms: Randomization, block design. Example: Placing positive controls in a checkerboard pattern. Practical application: Reducing edge effects and improving statistical power. Challenges are balancing randomization with practical constraints of robotic dispensing.
Plate Mapping – the digital representation of well positions and associat… #
Related terms: Well indexing, barcode linking. Mapping a 384‑well plate to a CSV file that lists compound IDs. Practical application: Tracking samples through the automation workflow. Challenges include preventing mismatches between physical and digital maps.
Plate Sealer – device that applies a breathable or airtight film to plate… #
Related terms: Foil seal, gas‑permeable membrane. Example: Using a heat‑seal to prevent evaporation during long incubations. Practical application: Maintaining consistent assay conditions. Challenges involve ensuring seal integrity without damaging plates or interfering with downstream detection.
Plate Reader Kinetic Mode – capability to measure signal changes over tim… #
Related terms: Real‑time assay, time‑course measurement. Example: Monitoring fluorescence increase from an enzymatic reaction every minute for 30 min. Practical application: Kinetic enzyme inhibition studies in HTS. Challenges include data volume, temperature control, and avoiding plate movement artifacts.
Plate Uniformity Assessment – evaluation of signal consistency across all… #
Related terms: Z′‑factor, coefficient of variation. Performing a uniformity test with a fluorescent dye to calculate CV. Practical application: Qualifying new plates before screening. Challenges include detecting subtle gradients and establishing acceptance criteria.
Positive Control – a well‑treated sample known to produce a maximal respo… #
Related terms: Reference compound, assay benchmark. Example: Staurosporine at 1 µM for a cytotoxicity assay. Practical application: Calculating Z′‑factor and monitoring assay drift. Challenges are ensuring stability of the control compound and avoiding saturation of the detection system.
Process Automation Software – the suite that programs, monitors, and logs… #
Related terms: Workflow engine, scripting interface. Example: Using Tecan EVOware to script a 96‑well dispensing protocol. Practical application: Reproducible execution of complex assay sequences. Challenges include software bugs, version incompatibility, and steep learning curves for non‑programmers.
Quality Control (QC) Metrics – statistical parameters that assess assay r… #
Related terms: Assay validation, performance indicators. Example: A Z′‑factor >0.5 Indicates an excellent assay. Practical application: Deciding whether to accept a screening run. Challenges are setting realistic thresholds for diverse assay types and maintaining QC over long campaigns.
Robotic Arm – a mechanical manipulator that transports plates between dev… #
Related terms: Gantry robot, deck mover. Example: A Hamilton robot arm moves plates from a liquid handler to an incubator. Practical application: Fully unattended screening cycles. Challenges include collision avoidance, precise positioning, and handling different plate formats.
Sample Tracking – the process of recording the movement and identity of e… #
Related terms: Barcode scanning, LIMS integration. Using RFID tags on plates to log each step. Practical application: Preventing sample mix‑ups in large screens. Challenges include ensuring reliable read‑outs and synchronizing data across multiple instruments.
Scheduling Software – tool that queues and prioritizes automated tasks to… #
Related terms: Job scheduler, queue manager. Example: A master scheduler assigns liquid‑handling jobs during off‑peak hours. Practical application: Optimizing throughput while avoiding conflicts. Challenges include handling emergency overrides and integrating diverse device APIs.
Signal‑to‑Noise Ratio (SNR) – the proportion of true assay signal relativ… #
Related terms: Dynamic range, assay sensitivity. An SNR of >10 is often desired for primary screens. Practical application: Guiding assay optimization decisions. Challenges involve reducing background fluorescence and ensuring consistent detector settings.
Software API (Application Programming Interface) – a set of protocols tha… #
Related terms: SDK, command line interface. Example: Using a Python API to trigger a plate reader from a custom script. Practical application: Integrating disparate devices into a unified workflow. Challenges include version drift, documentation quality, and security considerations.
Throughput – the number of samples processed per unit time, typically exp… #
Related terms: Capacity, assay speed. A 384‑well liquid handler may achieve 5 000 wells/hour. Practical application: Planning campaign timelines. Challenges are bottlenecks in downstream detection and data analysis, which can limit overall throughput despite fast dispensing.
Validation Run – a pilot screening that confirms assay robustness before… #
Related terms: Pilot study, pre‑screen. Example: Testing 100 compounds in duplicate to assess Z′‑factor. Practical application: Identifying protocol tweaks early. Challenges include allocating resources for a run that does not generate primary data.
Viscosity Compensation – adjustments made to dispensing algorithms to acc… #
Related terms: Shear‑thickening, tip speed. Using slower aspiration rates for high‑% DMSO solutions. Practical application: Preventing tip blockage and volume errors. Challenges involve measuring viscosity accurately and updating software parameters for each new reagent.
Workflow Integration – the seamless connection of all steps from cell cul… #
Related terms: End‑to‑end automation, process orchestration. Example: Linking cell seeding, compound addition, incubation, and plate reading without manual intervention. Practical application: Enabling 24/7 operation of a screening facility. Challenges include cross‑vendor compatibility, error propagation, and maintaining flexibility for assay-specific tweaks.
Yield Optimization – strategies to maximize the number of usable data poi… #
Related terms: Assay window, dynamic range. Adjusting seeding density to increase signal while avoiding saturation. Practical application: Improving hit detection rates. Challenges are balancing cell health with assay sensitivity and managing trade‑offs between speed and data quality.
Z′‑Factor – a statistical parameter that quantifies assay suitability for… #
5 Denote an excellent assay. Related terms: Assay robustness, QC metric. Calculated from the means and standard deviations of positive and negative controls. Practical application: Deciding whether a new assay can be deployed at scale. Challenges include variability in control wells, plate-to-plate drift, and the impact of outliers on the calculation.