Cell migration, barrier integrity, and transport across biological interfaces are fundamental processes in both normal physiology and disease progression. To study these phenomena in vitro, static insert plate formats, commonly known as Boyden chambers, are widely used. Systems such as Millicell® and Transwell® consist of a culture well containing a hollow insert equipped with a microporous membrane at its base, creating two interconnected compartments, the apical and basolateral sides, relative to the cell layer grown on the insert.
Beyond migration assays, insert plates are capable of modelling a variety of biologically distinct environments, including the tumor microenvironment, the blood-brain barrier, the gut epithelial barrier, and the respiratory tract's air-liquid interface (ALI). These configurations support assays focused on transport across gradients, such as drug permeability, cellular migration, and invasion assays, making insert plates a versatile and widely adopted membrane model across cancer research, neuroscience, and drug discovery.
Basic settings and uses of insert plates in dual-chamber cell culture experiments
The Insert Plate Workflow
Insert plate culture typically begins with seeding cells onto the apical side of the insert membrane at a defined density. Cell lines commonly used for barrier modeling, such as Caco-2 or MDCK, are seeded in complete growth medium on the apical side, while the basolateral chamber is filled with medium to maintain hydration and nutrient supply across the membrane. Following seeding, cells are incubated under standard culture conditions to allow attachment and initial growth.
Regular media exchanges in both chambers support cell health and remove metabolic waste. Culture duration varies by cell line; Caco-2 models, for example, require approximately 21 days to achieve full confluency and differentiation. Once a mature monolayer has formed, barrier integrity is assessed before conducting the assay, most commonly by measuring transepithelial electrical resistance (TEER), which provides a quantitative readout of tight junction formation and monolayer integrity. In some applications, the basolateral chamber bottom surface may also be seeded with a second cell population to enable cell-cell interaction studies.
Manual dual-chamber workflow and its handling challenges
Automating Insert Plate Cell Culture using the Cellmatic
The Cellmatic is a fully integrated automated cell culture system that consolidates liquid handling, incubation, and reagent storage into a single, walk-away platform. All cabinets operate under sterile conditions maintained through hydrogen peroxide vapor sterilization and HEPA filtration, coordinated by Suite, Formulatrix's intelligent scheduling software that automatically executes culture tasks using user-defined parameters without manual intervention.
Precise Liquid Handling for Insert Plate Formats
The Cellmatic supports automated insert plate maintenance through two integrated liquid handling components, each suited to different plate formats. For high-density insert plates, such as 96-well Millicell® plates, the Reagent Exchanger (RX) performs media exchange using its 96-channel aspirator head, which allows precise aspiration from both chambers while managing hydrostatic pressure to avoid stressing the cell layer and/or disrupting the insert membrane. Fresh media is then replenished through controlled sidewall dispensing at an adjustable flow rate, completing a full exchange cycle in under 1 minute. For seeding, the eight-channel dispenser delivers cell suspensions uniformly across the plate (CV <5% at 50 µL).
For larger surface area formats such as 24-well Millicell® plates, liquid handling is performed by the FLO i8® PD. With eight independent channels and per-channel volume control, the FLO i8 PD provides flexible, tip-based liquid handling across a volume range of 10–1000 µL (CV ±1 – 4%). Integrated dynamic liquid level tracking ensures accurate, contamination-free transfers and can accommodate differential treatment across columns as needed.
Media exchange in a 96-well plate
Media exchange schedules and seeding protocols are orchestrated by the Cellmatic Suite Software, which executes all tasks (seeding, media exchange, imaging, and data export) on a user-defined schedule without scripting. This ensures no maintenance step is missed and that culture progression remains on a consistent, reproducible timeline, which is critical for achieving reliable and repeatable cell culture outcomes.
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.
