Cell-based assays are a cornerstone of biological research, providing physiologically relevant models for studying cellular responses to compounds, genetic alterations, and environmental stimuli. To increase experimental throughput and reduce reagent consumption, assay miniaturization using multiwell microplate formats such as 96-well and 384-well plates has become standard practice, allowing many conditions to be tested in parallel while also reducing reliance on animal models.
Preparing cells for these assays is labor-intensive. A typical workflow includes multiple interdependent steps: expanding cells in culture, maintaining cultures under controlled incubator conditions, monitoring growth and morphology, executing scheduled media exchanges, performing cell counts to assess viability, and seeding cells into assay plates at defined densities, all before the actual assay even begins. Each of these steps carries its own technical demands and, when performed manually, its own sources of variability.
Inconsistent pipetting technique, variable timing between steps, and the physical limitations of managing multiple plates simultaneously all introduce well-to-well and plate-to-plate variability that can directly compromise assay quality and reproducibility. At higher throughput, these challenges are compounded further. More plates mean more handling, more opportunity for error, and greater demands on operator time.
As an automated cell culture system (CCS), the Cellmatic® supports standardized and reproducible cell-based experiments in parallel by integrating liquid handlers with essential supporting modules for cell growth, including incubators and reagent storage. Liquid handling within the Cellmatic is performed by two modules, the FLO i8® PD and the Reagent Exchanger (RX), each offering distinct advantages for managing multiwell plate assays. The system is further supported by the Suite application, which includes a built-in scheduler to enable smooth automation execution and precise experiment scheduling.
Automated Cell Plating into the Microplates
Working with the Cellmatic can begin by registering a manually prepared cell culture as a source plate for downstream automated processing within the CCS. To better adapt to the system, a 1-well plate (Greiner) is recommended as a replacement for traditional T flasks, offering up to 95 cm² of growth surface area. In addition to 1-well plates, the Cellmatic is compatible with various multiwell formats, including 6-well circular plates, 8-well rectangular plates, 96-, 384-well plates and others.
Automated cell culture preparation in Formulatrix’s Cellmatic for bioassays
During experiment setup, the Suite application allows users to define not only passaging parameters but also how cells will be plated into future daughter assay plates (target plates). Automated cell counting is performed using the FLO i8 PD for the preparation and the Formulatrix Imager with a dedicated counting plate and built-in algorithms optimized for trypan blue exclusion assays to assess cell viability.
Cell plating is performed by the system’s liquid handlers, the FLO i8 and RX. The FLO i8 PD performs plating using a pipetting approach, offering cell suspension trituration and greater flexibility in plating patterns. In contrast, in RX-based plating, dissociated cells are pooled in a trough reservoir equipped with a magnetic stirrer to maintain suspension homogeneity. The cell suspension is then dispensed through eight nozzles, enabling rapid plating into some or all wells of a plate. Both liquid handlers support plate tilting and rocking features to address concerns related to suspension homogeneity and liquid accessibility.
Cell dislodging, mixing and seeding into daughter plates
Cell plating in a 384-well plate
Automated Maintenance of Microplate-Format Cell Cultures
After plating, cultures are maintained under controlled incubator conditions (example: 37°C, 5% CO₂, 95% humidity). Cell growth and morphology are continuously monitored using the integrated Imager to track confluency and culture health. Feeding schedules are managed through the Suite application by the user, allowing media exchanges to be executed automatically at defined time intervals.
Automating imaging of a 1-well plate
Media exchange in a 96-well plate
The Cellmatic supports flexible feeding strategies, including full or partial media exchange, with optional wash steps prior to fresh media addition. These workflows are executed by the integrated RX, purpose-built for high-throughput, plate-wide media exchange across high-density multi well plate formats.
Liquid handling properties of the FLO i8 PD and RX for media exchange
The FLO i8 PD uses 8 independently controlled channels equipped with disposable positive displacement tips, which incorporate conductive strips for resistance-based liquid level detection and tracking. Each channel can be controlled independently, enabling either simultaneous or sequential aspiration and dispensing across selected wells. This provides high flexibility for complex well mapping and multi-reagent workflows. In the passaging workflow, a unique liquid handling sequence is used to dislodge the cells from the bottom of the plate, resulting in a high collection efficiency.
In contrast, the RX operates using fixed, one-way fluid paths. It supports dispensing and aspiration across 1-, 384-well plates. The RX dispensing nozzles are designed for gentle, non-contact sidewall dispensing, making them well-suited for sensitive or loosely adherent cells while enabling rapid and uniform full-plate processing. In addition, the RX features an automated self-cleaning procedure that helps mitigate the risk of contamination or clogging throughout all liquid pathways.
Application Notes
Automated Gentle Media Exchange for Loosely Adherent HEK-293T Cells with the Reagent Exchanger (RX)
HEK-293T cells are prone to detachment, making gentle liquid handling critical during media exchange. The RX automates aspiration and dispensing, reducing cell loss compared with manual pipetting.
iPSC Maintenance in a 6-well Plate Using the Cellmatic™
iPSC maintenance demands daily monitoring, media exchange, and passaging — all labor-intensive and prone to variability. The Cellmatic automates these tasks to deliver consistent, reproducible iPSC cultures with reduced manual effort.
