Expansify™ High-Density Cell Culture FAQ

1.  What is the Expansify™ platform?

Expansify is XDemics’ family of high-density cell cultureware designed to help researchers consistently grow more cells in a smaller footprint. Compatible with standard incubators, laboratory workflows, and automated platforms, Expansify products have been adopted across a broad range of applications to improve productivity, efficiency, and scalability.

Unlike conventional plates and flasks, Expansify cultureware uses XDemics’ High-Density Cell Respiration™ (HDCR™) technology, which mimics the close proximity of cells to capillaries in living tissue and helps overcome the oxygen delivery limitations of conventional cell culture.

HDCR uses a thin, gas-permeable silicone membrane with parallel ridges and open grooves. Each ridge functions like an artificial capillary, supplying oxygen to the grooves on either side. The grooves provide replicative niches where cells can divide. Repeated across the membrane surface, this geometry creates an array of cell culture niches, referred to as unit cells, and forms the core technology used in every Expansify device. 

The Expansify 24-Well Plate and 1-Well Plate are commercially available, while the 96-Well and 6-Well plates and the larger-scale Gigacell™ Tray are planned for release. Contact XDemics Support for product release timelines.

2. What cell culture challenges is Expansify designed to address? 

Expansify is designed to address limited cell yields, large and cumbersome culture vessel footprints, frequent passaging, and labor-intensive cell culture workflows. Its shared platform architecture also supports scale-up across device formats, reducing the need to transition between fundamentally different culture systems. 

The HDCR™ architecture supports high-density cultures through increased oxygen delivery and CO₂ removal rates in a compact, static, shear-free, culture format without mechanical agitation. It also supports cell expansion from low seeding densities and extended culture periods, providing flexibility for applications such as cell line development and clonal expansion.

In suitable workflows, a single Expansify plate can consolidate cultures that would otherwise require multiple T-flasks.  This reduces transfers, passaging steps, and other labor-intensive, open manipulations that create additional opportunities for contamination. 

Expansify plate formats are static and compatible with all standard incubators. They do not require external tubing, ports, fluidic connections, or devices intended to vigorously mix, agitate and aerate samples, such as orbital shakers or platform rockers. 

For suspension cultures, cells grown in Expansify cultureware are retained within the cell culture niches and can be expanded to high density without agitation. This provides two practical benefits:

• Medium exchange: Medium can be exchanged without harvesting, centrifuging, or resuspending the cells.
• Product collection: Product-containing supernatant can be collected directly without first harvesting and centrifuging the culture.

Downstream centrifugation or clarification requirements remain process dependent. In some cases, product recovery may be improved by gently fluidizing the cells to release product retained within the cell expansion grooves.  Application-specific data on cell recovery, recombinant protein expression, and primary cell expansion are provided in the relevant sections below and in the Application Notes & Protocols section of our website. Culture conditions should be optimized and verified for each cell type, application, and process.

All Expansify formats, regardless of size, share the same common HDCR™ platform architecture. Scaling within the Expansify product line can reduce the need to transition between fundamentally different culture systems as processes require scale-up, limiting the introduction of new process variables, changes in biology, and requirements for additional optimization.

3. What types of applications is Expansify designed for?

Expansify is designed for research and process-development applications that benefit from increased cell yield, improved throughput, efficient use of incubator space, streamlined handling and operations, reduced risk of contamination, as well as efficient process scale-up.

Expansify applications and workflows include:

• Cell line development, expansion from low cell seeding densities, and clonal expansion
• Automated cell culture, high-throughput screening (HTS), and process optimization
• Generation of large cell populations for data-intensive biology applications (e.g., functional genomics and AI-enabled biological model training)
• Recovery and expansion of cells after electroporation
• Expansion of primary, therapeutic, and stem-cell populations such as T cells, CAR-T cells, tumor-infiltrating lymphocytes (TILs), natural killer cells (NK), induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs)
• Expansion of cells for recombinant protein production, including mAbs and other biologics (e.g., hybridoma, etc.)
• Expansion of host cells used to propagate replication-competent viruses
• Producer cells used for virus and viral-vector production, including AAV.  Production workflows involving viral vectors and engineered host cells
• Spheroid, aggregate, and organoid culture
• Cell banking, scale-up studies and development of large-scale cell expansion workflows

Performance is application-dependent and may vary with cell type, culture medium, seeding density, feeding strategy, culture duration, and other process conditions. Application-specific optimization is recommended.

4. Can Expansify support expansion from low seeding densities for cell line development?   

Yes. In one study, HEK293T cells were seeded in an Expansify 24-Well Plate ranging from 500 to 100,000 cells per well, equivalent to 250–50,000 cells/cm². Across the tested seeding inputs, cultures yielded 22–36 million viable cells per well at harvest, with >90% viability. At the lowest seeding input, 500 cells per well expanded to approximately 22 million cells per well by day 11, representing an approximate 44,000-fold expansion. These results demonstrate substantial expansion from low starting cell numbers and suggest that Expansify may reduce intermediate expansion steps during cell line development.

5. Can Expansify support CHO cell culture and monoclonal antibody (mAb) production?

Yes. In internal studies, the Expansify 24-Well Plate has supported CHO-K1 cell yields of approximately 15–20 million cells per well. In a study using the NISTCHO stable cell line expressing a humanized IgG1 monoclonal antibody, the Expansify 1-Well Plate was compared against a conventional 500 mL shake flask. Specific mAb productivity was comparable between the two culture systems. The antibody produced in Expansify demonstrated antigen-binding activity, identity, glycosylation, thermal stability, and charge characteristics comparable to those of the antibody produced in the shake-flask control and the purified mAb control provided by NIST. The Expansify-produced sample contained approximately one-third of the host-cell DNA impurities and produced slightly lower levels of high-molecular-weight aggregates than the control shake flask. Under the conditions evaluated, these results support the use of Expansify for high-density CHO culture, mAb production, and functional screening without requiring vessel agitation. 

6.  How can Expansify reduce T-flask use, hands-on time, and contamination risk during cell expansion?

In a client study, one Expansify 1-Well Plate was used in place of a workflow requiring 15 T-225 flasks for a 17-day expansion of adherent MDA-MB-468 breast cancer cells. Both workflows began with 2 million cells. The T-flask workflow used one flask, followed by four flasks and then ten flasks, whereas the Expansify workflow used a single plate without intermediate passaging or vessel-to-vessel scale-up. Expansify grew 291 million cells, corresponding to 146-fold expansion, compared with 262 million cells and 131-fold expansion using the T-225 flasks. Expansify reduced dissociation and harvest operations from 15 to one, decreased open-vessel manipulations from 31 to 5, an 84% reduction, and reduced estimated hands-on time from approximately 100 minutes to 20 minutes, an 80% reduction.

These study-specific results demonstrate the potential of Expansify to streamline adherent cell expansion, increase operational efficiency, reduce operator time, and decrease the number of open-vessel manipulations that create opportunities for contamination.

7. Can Expansify support T cell expansion for CAR-T research?

Yes. Expansify can support T-cell expansion in CAR-T research and process development workflows. Its gas-permeable geometry localizes cells within protected, shear-free niches that support close cell-to-cell interactions and high-density cell growth under static culture conditions. In studies comparing Expansify with flat gas-permeable membrane cultureware, Expansify cultures showed greater representation of less-differentiated naïve and central memory T-cell subsets and reduced representation of effector memory and effector subsets. Positivity for the exhaustion-associated markers TIM-3, LAG-3, and PD-1 was also lower in Expansify cultures. These cultures also exhibited greater IL-2 secretion, higher viable T-cell yields, and improved viral vector transduction efficiency. CAR-T cells expanded more than 100-fold, reached cell densities of 1-3 × 10⁷ cells/cm², and retained tumor-cell killing activity after re-challenge. These findings were observed under the conditions evaluated and may vary with T-cell source, activation method, vector system, and culture conditions.

8. Can Expansify support automated cell culture?

Yes. Expansify plate formats are designed to support automated cell culture and integration with liquid handling workflows. These ANSI/SLAS-compatible formats are designed for integration with automated plate-handling and liquid-handling systems and share the same HDCR™ three-dimensional architecture across plate formats, simplifying the translation of automated workflows across plate formats and scales. The static, shear-free culture environment operates without mechanical agitation and can reduce intermediate passaging, vessel transfers, and other manual interventions, while plate-based imaging access can support automated culture monitoring. These features enable automated workflows for applications including high-throughput screening, cell line development, CAR-T, organoid and stem-cell culture, functional genomics, proteomics, and metabolomics. Automation compatibility should be verified for the specific instrument, plate-handling configuration, and workflow.

9. Can Expansify be used to expand mesenchymal stem cells?

Yes. Under the conditions tested, Expansify supported high-density expansion of adipose-derived (AD-MSCs) and bone marrow-derived mesenchymal stem cells (BM-MSCs) while preserving MSC phenotype. On vitronectin-coated surfaces at 5% O₂, Expansify achieved 5.5-fold greater AD-MSC expansion and 8.2-fold greater BM-MSC expansion than conventional polystyrene vessels. Through day 13, cells maintained positive expression of CD73, CD90, and CD105 markers, while CD45-positive cells remained at or below 2%. In a separate study using canine adipose-derived MSCs (cAD-MSCs), the Expansify 24-Well Plate achieved 60.5-fold expansion and an area-normalized yield of 15.13 million cells per 25 cm², with 98-100% post-detachment viability. The expanded cAD-MSCs also retained adipogenic, chondrogenic, and osteogenic differentiation capacity.

10. Can Expansify support cell recovery after electroporation?

Yes. In a study using HEK293T cells electroporated with a fluorescent reporter plasmid, cells recovered in the Expansify 24-Well Plate showed 80% post-electroporation cell viability, compared with 50% in a T-75 flask. This higher viability was accompanied by a 4.6-fold greater fluorescent protein signal. Under the conditions evaluated, these results demonstrate the potential of Expansify to improve recovery of viable cells and increase fluorescent protein signal following electroporation, addressing an important bottleneck in cell-engineering workflows. Electroporation outcomes should be optimized for the specific cell type, electroporation system, pulse conditions, and nucleic acid cargo.

11. Can Expansify be used to improve virus production?

Yes. In an electroporation-based virus production study conducted in the laboratory of Dr. Charles Rice at Rockefeller University, cultures grown in an Expansify 24-Well Plate achieved approximately 20-fold higher viral titers than T-75 flask controls. Under the conditions evaluated, these results demonstrate the potential of Expansify to support high-titer virus production following electroporation.  Expansify has also been used to improve oncolytic virus production, compared to T-flask-based processes.

12. Can Expansify support spheroid, aggregate, or organoid cultures?

Yes. Expansify culture systems can support spheroid, aggregate, and organoid-related workflows across a variety of cell types. The culture environment promotes close cell-cell interactions while providing efficient gas exchange near the gas-permeable culture surfaces. 

Within each cell culture niche, aggregate and spheroid growth is physically constrained to a maximum diameter of approximately 400 µm. This geometry keeps cells no more than approximately 200 µm from an oxygenating surface. By limiting aggregate diameter and oxygen diffusion distance, the niches can promote more consistent spheroid sizes and reduce the likelihood of developing hypoxic or necrotic cores.

Depending on the cell type and culture conditions, cells may form compact spheroids, multicellular aggregates, or more complex three-dimensional structures. The XDemics scientific team can provide guidance on format selection, culture conditions, and workflow design for specific 3D cell culture applications. 

13. Can Expansify cultureware be coated with extracellular matrix proteins?

Yes. Expansify cultureware is compatible with a variety of extracellular matrix (ECM) coatings, including vitronectin, fibronectin, and laminin.  ECM coating can improve attachment, spreading, and long-term culture performance for many adherent cell types. XDemics provides representative coating protocols and tested conditions for commonly used ECM proteins, along with guidance for evaluating additional substrates on the Expansify platform. See the XDemics Application Notes & Protocols for coating methods and cell-specific examples.

1.  How does Expansify differ from traditional plates and flasks?

Traditional plates and flasks depend on oxygen diffusing through the culture medium to reach the cells. As cell density increases, oxygen transfer can become limiting. Achieving higher yields may therefore require more vessels, a larger culture footprint, more frequent passaging, more open-vessel manipulations, and more risk of contamination.

Expansify uses a different approach. Its patented HDCR™ architecture consists of a series of parallel ridges and grooves, where each ridge is designed for optimal oxygen delivery to cells, and each groove functions as an ideal replicative niche for cell growth. This design supports high-density cell culture under gentle, shear-free conditions without shaking, stirring, or sparging. Expansify can generate more cells within a smaller footprint while remaining compatible with standard incubators and laboratory workflows.

2.  Are Expansify plates bioreactors?

Yes. Expansify devices are not traditional stirred-tank, rocking platform, or perfusion bioreactors. Expansify plates are single-use cell cultureware that combine the simplicity of traditional cultureware with HDCR™’s gas-permeable architecture for high-density cell growth in an agitation-free manner.

Expansify plates operate under static, shear-free conditions without mechanical agitation, sparging, tubing, ports, or connectors. They fit standard laboratory incubators and support efficient oxygen delivery and CO₂ exchange without specialized bioreactor equipment.

This allows Expansify to support applications that might otherwise require more conventional vessels, a larger culture footprint, or a more complex expansion system. The plates can often be incorporated into existing laboratory workflows without the equipment and operational requirements associated with conventional bioreactors.

3.  Does Expansify require specialized equipment?

Expansify well plates are designed for use with standard cell culture equipment and media and do not require pumps, sparging systems, mechanical agitators, or other specialized infrastructure.

The well plates integrate into existing laboratory workflows and can be operated using standard incubators and common cell culture equipment. This allows users to adopt Expansify without significant changes to their facilities, equipment, or operating procedures.

1.  How does the Expansify platform support cell culture scale-up?

Expansify supports linear scaling of available culture area across device formats, from the 96-Well Plate through Gigacell™. As scale increases, the same repeating HDCR unit-cell architecture is maintained across a larger membrane, preserving the core culture geometry rather than requiring a transition to a fundamentally different culture system.

Maintaining the same gas-permeable membrane and three-dimensional niche architecture provides a consistent basis for translating process conditions from screening and process development into larger-scale cell-expansion workflows. This consistency can reduce the number of new process variables introduced during scale-up, although some format- and application-specific optimization may still be required.

Achievable cell yields remain process-dependent and will vary with cell type, medium formulation, seeding density, feeding strategy, culture duration, and process objectives.

2. Can existing CAR-T or cell therapy research workflows be translated into Expansify?

Yes. Established CAR-T and cell therapy research workflows can be adapted to Expansify using existing process parameters as starting conditions. These may include media formulation, T-cell activation and transduction methods, cytokine supplementation, seeding density, feeding strategy, and culture duration.

During process transfer, optimization can be focused on format-specific parameters such as working volume, medium exchange, sampling, cell distribution, and harvest procedures. This allows researchers to evaluate Expansify within an established cell therapy workflow while minimizing unnecessary changes to the underlying biological process.

Data generated during this evaluation can support cell therapy process development, scale-up, and technology transfer.

3. How do I choose the right Expansify format for my application?

Expansify format selection is typically guided by the stage of process development, target cell yield, number of conditions being evaluated, and intended downstream application. The Expansify 24-Well Plate is well suited for parallel process development and optimization studies, including media evaluation, feeding strategy development, seeding-density optimization, and multi-parameter screening. The Expansify 1-Well Plate enables the generation of larger cell quantities while providing an intermediate scale for evaluating culture performance and workflow execution. Gigacell™ is being developed to support larger-scale cell expansion and the development of manufacturing-relevant processes.

Expansify formats can be used sequentially to progress from process optimization to larger-scale cell expansion within a common platform architecture. This approach can support continuity across development stages while reducing the need to transition between fundamentally different culture systems. If you are uncertain which Expansify format is most appropriate for your application, contact XDemics Support to review and discuss your workflow.

1. Why use the Expansify 24-Well Plate for process development?

The Expansify 24-Well Plate is designed for screening and process development, allowing users to evaluate multiple medium formulations, seeding densities, feeding strategies, culture durations, and other process parameters in parallel under static, high-density culture conditions.

Each well incorporates the same gas-permeable membrane and repeating HDCR unit-cell architecture used throughout the Expansify platform. This allows the 24-Well Plate to serve as a representative small-scale development model for larger Expansify formats. Scientists can compare conditions and include additional replicates while using fewer cells, less medium, and less incubator space than larger-format studies.

Conditions identified in the 24-Well Plate can provide a relevant starting point for studies in the 1-Well Plate and Gigacell™ Tray. Culture performance should still be confirmed as scale increases, and process parameters should be adjusted when necessary.

2. What is the purpose of the Expansify 1-Well Plate?

The Expansify 1-Well Plate is an intermediate-scale culture format designed to bridge process optimization and larger-scale cell expansion.  It enables users to increase culture scale, generate larger cell quantities for downstream applications, and evaluate process performance and workflow execution before progressing to larger culture systems. Following condition optimization in the Expansify 24-Well Plate, the 1-Well Plate can be used to assess whether selected process conditions remain suitable at increased culture scale.

The format can also support evaluation of handling procedures and generation of process-development data before progression to larger Expansify™ formats, such as the Gigacell™.

3. What is the Gigacell™ Tray and is it commercially available?

Gigacell™ is a large-scale, closed Expansify cultureware format under development to support large-scale high-density cell expansion for cell therapy, translational research, and manufacturing-oriented applications.  Built upon the same core HDCR™ platform principles as other Expansify formats, Gigacell™ combines efficient gas exchange with gentle static culture conditions, enabling the expansion of large cell quantities while maintaining workflow familiarity and compatibility with standard laboratory infrastructure.  Gigacell™ is designed to facilitate the progression of cell culture processes from development-scale studies to manufacturing-relevant workflows, supporting process development, scale-up, and technology transfer activities in a closed system.

Like all Expansify formats, Gigacell™ operates statically inside a standard incubator, which maintains temperature and atmospheric gas conditions. Gigacell™ includes built-in closed aseptic connections for cell seeding, feeding, sampling, and harvest. Ports with inlets positioned near the cell-expansion niches can also be connected to automated analytical systems to support real-time monitoring of culture metabolites or other relevant product quality attributes.

Gigacell™ is under development and is not currently commercially available. A release date has not been announced. Contact XDemics Support for current development and availability information.

4. What types of workflows is Gigacell™ being developed for?

Gigacell™ is being developed to support a broad range of large-scale cell expansion and manufacturing-oriented applications where high cell yields, process scalability, and operational efficiency are important considerations.  Gigacell™ will support translation of processes established in smaller Expansify formats into a larger format while preserving the same core HDCR unit-cell architecture.

Representative applications include:

• Engineered T cell and other immune cell expansion workflows
• Cell expansion for seed-train development and scale-up 
• Cell expansion for biobanking and cell generation workflows
• Process development / optimization
• Host cell expansion for viral vector and biologics production
• Applications requiring large-scale cell generation within a static culture environment
• Workflows where consistency, reproducibility, and efficient handling are critical

As a flexible culture platform, Gigacell™ is intended to support multiple cell types and process requirements, subject to application-specific evaluation, enabling users to translate and scale established workflows within the Expansify ecosystem.

1. What material and biocompatibility information is available for Expansify cultureware used in cell therapy research?

Expansify cultureware has been developed with the requirements of cell therapy research, process development, and biomanufacturing workflows in mind. Material selection and product design incorporate considerations related to biocompatibility, cytotoxicity, sterilization, and overall cultureware performance. The cell-contacting culture surfaces are Class VI medical-grade silicone and polystyrene.

Product-specific material specifications, biological evaluation documentation, and supporting technical information are available upon request for technical evaluation, process development, and regulatory assessment.

2. Are Expansify products for research use only?

Yes. Current Expansify products are for research use only (RUO).  They are intended for laboratory research and process-development applications, including studies that generate data relevant to future scale-up and manufacturing workflows.

The Expansify platform includes multiple culture formats that enable users to progress from early-stage experimentation and process optimization to larger-scale expansion studies within a common platform architecture. This approach supports the generation of development data across stages of a program while maintaining continuity in culture environment, handling workflows, and process design. Many users begin with smaller formats for condition screening and process optimization before advancing to larger formats as process requirements and cell production needs evolve.

Gigacell™ is under development. Contact XDemics Support for the current release plan, intended use, fluid-path configuration, and supporting documentation.

1. How can uniform cell distribution be achieved during culture initiation?

After seeding, gently homogenize the cell suspension using the recommended mixing method for the Expansify format. This distributes the cells throughout the medium before they settle into the cell-expansion niches. Uniform initial distribution helps prevent localized regions of excessively high or low cell density.

Avoid vigorous pipetting, foaming, or introducing air bubbles, which may disrupt cell distribution or interfere with cell settling within the culture niches. Following mixing, suspension cells settle into the niches, while adherent cells settle and attach to the prepared culture surface. Refer to the Expansify Quick Start Guide for format-specific seeding and mixing instructions.

2. Should the Expansify culture vessel be rocked or swirled after seeding?

In most cases, no. Gentle mixing immediately after seeding is generally preferred to achieve uniform cell distribution, using the method recommended for the specific Expansify™ format.

Gentle rocking or swirling may be appropriate in the Expansify™ 1-Well Plate when working at low liquid volumes,  but it is generally unnecessary at recommended working volumes. Excessive rocking or swirling can cause fluid sloshing, which may lead to uneven cell distribution and reduced seeding uniformity.

3. Do cells growing in Expansify need to be shaken or agitated?

No. Expansify cultureware is designed for static, shear-free cell culture and does not require continuous shaking or mechanical agitation during routine culture. Both adherent and suspension cells grow within the oxygenating cell expansion niches, which are engineered to facilitate efficient gas exchange without continuous mechanical agitation during growth. As a result, the platform is not intended for continuous mechanical shaking, which can disrupt the culture environment and negatively impact cell health and performance. In the HDCR™ architecture, the tops of the fins are rounded to facilitate cells settling into the niches. Suspension cultures typically accumulate within these niches and expand volumetrically, resulting in increasing cell density throughout the culture depth.  Gentle mixing during seeding, media handling and harvest is separate from continuous mechanical agitation during culture.

4. When should I feed cells or exchange medium in Expansify?

Use the growth and feeding behavior of an established culture process as a starting point, then confirm and refine the schedule in Expansify. The goal is to feed the cells or exchange the medium before nutrient depletion or metabolite accumulation begins to limit growth, viability, productivity, or another relevant performance measure.

Efficient gas exchange does not eliminate the need for medium management. The gas-permeable membrane supports O₂ delivery and CO₂ removal, but it does not replenish nutrients or remove nonvolatile metabolic byproducts that accumulate in the medium. Expansify cultures may therefore require feeding or medium exchange even when gas exchange remains sufficient to support cellular respiration. Medium requirements are driven primarily by viable-cell number and metabolic activity, not by vessel footprint alone. Although Expansify can support more cells within a compact footprint, those cells still require adequate nutrients and metabolite management.

A practical approach is:

• Generate a complete reference growth curve.
  Characterize the cell line in your non-Expansify culture device under its typical operating conditions. The growth curve should capture the lag, exponential, stationary, and death phases. Identify the final sampled time point that remains within sustained exponential growth before the growth rate begins to decrease. At that time point, record the total viable cell yield and total medium volume. For adherent cultures, also record the viable cell yield per unit of culture area. If the reference process includes feeding or medium exchanges, document their timing and volumes. 
• Calculate the reference cell-to-medium ratio.
  Divide the total viable-cell yield at the final exponential-growth time point by the total medium volume to calculate a ratio of viable cells per milliliter of medium. For adherent cultures, this value does not represent a suspension-cell concentration; it represents the number of viable cells supported per milliliter of medium under the experimental conditions.
• Translate the ratio to Expansify.
  Multiply the reference cell-to-medium ratio by the selected Expansify fill volume to estimate the number of cells that volume may support before feeding or medium exchange is required. Combine this estimate with the expected growth rate to project when the culture may reach that point. The same relationship can provide an initial estimate of the fresh-medium volume needed to support the projected cell number during the next media exchange. 
• Confirm the estimate experimentally.
  During an initial Expansify study, evaluate the culture before and around the estimated feeding point. Monitor viable-cell yield, growth rate, viability, nutrient consumption, and relevant metabolites such as glucose and lactate. Do not rely on medium color alone to determine when feeding is required. 
• Refine the schedule.
  Use the results to adjust the timing, frequency, and volume of medium exchanges. If nutrient depletion or metabolite accumulation occurs before the target yield is reached, feed earlier or increase the exchange volume. If growth slows while nutrients remain adequate, consider other limitations, including occupancy of the cell-expansion niches. Feeding can address medium-related limitations but does not increase the physical capacity of the culture format.

These calculations should be treated as initial planning estimates because growth in the reference device may also be affected by surface area, crowding, or cell-type-specific limitations. If reference-process data are unavailable, use a small exploratory study to establish these relationships.

For further assistance translating an existing process or designing an initial Expansify study, contact XDemics Support.

5. What are SureShelves™ and how are they used?

SureShelves™ are integrated liquid-handling features in Expansify well plates that support consistent media addition and aspiration. They provide defined positions for Pasteur and serological pipettes and serve as volume references during media addition and aspiration. Users can select a shelf based on the desired residual volume, helping standardize media exchanges while minimizing disruption to the cell culture. For accurate aspiration, XDemics recommends using a fine-tipped glass or disposable polystyrene Pasteur pipette, or another aspiration device fitted with an appropriately sized fine tip. See the Expansify Quick Start Guide for format-specific SureShelves™ handling instructions.

6. How do Expansify plates retain cells during media exchange?

Expansify plates retain suspension cells during media exchange by allowing cells to naturally settle within the recessed culture niches formed by the HDCR architecture. These niches position cells away from the primary aspiration flow path, helping reduce cell loss as spent medium is removed.

In suitable suspension cell culture workflows, this cell-retention mechanism can reduce or eliminate the need for centrifugation-based cell recovery during routine medium exchange. SureShelves™ provide defined aspiration locations for removal of spent medium or product-containing supernatant while minimizing disturbance to the culture.

7. Should media exchanges be partial or complete?

Both partial and complete medium exchanges can be appropriate depending on the cell type and culture process. Complete medium exchanges provide more complete nutrient replenishment and removal of accumulated soluble metabolites. Partial exchanges may be advantageous when cells benefit from conditioned medium, autocrine signaling factors, or other secreted components that support growth and function.

The appropriate exchange strategy should therefore be selected and optimized based on the metabolic and biological requirements of the culture rather than on the Expansify platform itself.

8. How can culture density be monitored during expansion?

Cell density during expansion can be assessed using periodic viable cell counts and imaging, supported by measurements of nutrient consumption, metabolite accumulation, and other application-specific culture parameters.

As cultures expand, cells progressively occupy a greater proportion of the available growth space. Increasing occupancy of the culture niches, slowing cell growth, nutrient depletion, or metabolite accumulation can provide additional indications that the culture is approaching a process-specific density limit.

9. Why can medium stay red during active cell growth in Expansify?

Many cell culture media contain phenol red, a pH indicator. Phenol red color reflects medium pH rather than cell number or growth rate. Medium pH is influenced by the buffering system, incubator CO₂ concentration, gas exchange, and cellular metabolism.

Expansify systems are engineered to support efficient gas exchange, including the removal of carbon dioxide from the culture environment. 

Under suitable culture conditions, efficient gas exchange can contribute to maintaining medium pH within its expected range, so phenol-red-containing medium may remain red or exhibit less pronounced acidification during active cell growth.

Medium color alone should not be used as a surrogate for cell growth, metabolic activity, or nutrient availability. Cells can continue to consume nutrients and accumulate nonvolatile metabolic byproducts, such as lactate, even when the medium remains red. Culture status should therefore be evaluated using appropriate measurements such as viable cell density, nutrient and metabolite concentrations, and pH when relevant.

10. What laboratory supplies and consumables are recommended for Expansify well plates?

Expansify well plates are designed for use with standard laboratory equipment. However, the following supplies are required or recommended for accurate medium exchange and gentle cell handling.

Required for SureShelves aspiration

• A fine-tipped aspiration device is required to remove medium accurately at the SureShelves positions. Suitable options include a sterile glass Pasteur pipette, a sterile disposable polystyrene Pasteur pipette, or another aspiration device fitted with a fine aspirating tip. 
• The fine aspiration point allows controlled medium removal, helps maintain the intended residual volume, and reduces the risk of unintentionally removing cells during medium exchange.

Recommended for mixing and cell handling

• Expansify 24-Well Plate: sterile wide-bore P1000 pipette tips are recommended for mixing, resuspension, and cell collection, particularly when handling high-density cultures in a 24-Well Plate format. Wide-bore tips reduce pipetting-associated shear and allow concentrated cell suspensions to be mixed and transferred more gently. 
• Expansify 1-Well Plate: sterile standard 10, 25, 50, and 100 mL serological pipettes.

Not recommended

• Common 2 mL aspirating pipettes are not recommended for routine SureShelves operation when used without a fine tip. Their larger opening can reduce aspiration precision, particularly at the lowest SureShelf position. 
• If a fine-tipped aspiration device is unavailable, a standard aspirating pipette may be fitted with a 200 µL non-filter micropipette tip to create a narrower aspiration point.

Refer to the Expansify Quick Start Guide for format-specific equipment and handling instructions.

11. How can cells be imaged in Expansify cultureware?

All Expansify culture formats are compatible with routine cell imaging and can be imaged similarly to conventional tissue culture vessels. Expansify cultureware is compatible with inverted brightfield, phase-contrast, and fluorescence microscopy. Confocal microscopy is also compatible with Expansify well plate formats, although Gigacell™ is not designed for confocal imaging applications.

When imaging cultures in Expansify, the primary consideration is identifying and maintaining a consistent focal plane within the three-dimensional culture architecture. Unlike conventional two-dimensional monolayers, cells within Expansify occupy a structured microenvironment composed of oxygenating surfaces and culture niches that extend through the depth of the device.

For brightfield and phase-contrast imaging, the uppermost oxygenating surfaces are typically identified by the appearance of refracted light along the tops of the rounded ridges. Once this focal plane has been located, users can adjust focus through the depth of the culture to visualize cell distribution within the underlying niches.

The tops of the fins are rounded to facilitate cell settling into the niches.  Suspension cultures typically accumulate within these niches and expand volumetrically, resulting in increasing cell density throughout the culture depth. Adherent cultures attach to the ECM coating or silicone surfaces and subsequently expand outward across the available culture area, forming multicellular structures that span multiple oxygenating surfaces. For longitudinal imaging studies, maintaining a consistent focal plane between imaging sessions is recommended to facilitate accurate assessment of culture morphology, growth, and cell distribution over time.

Because Expansify uses a three-dimensional HDCR architecture, cells may be distributed across multiple focal planes within the culture niches rather than along a single flat surface. Imaging can therefore be used to assess cell morphology, spatial distribution, niche occupancy, and changes in culture density over time, with interpretation accounting for the depth of the culture architecture.

Expansify well plates also include localization markers that allow defined regions of the culture to be identified and revisited during longitudinal imaging studies. This supports more consistent comparison of cell growth, morphology, and distribution across multiple time points.

12. How are cells harvested from Expansify culture systems?

Expansify culture systems are designed to support established cell harvest and recovery methods for both suspension and adherent cell cultures. Suspension cells can be resuspended and collected directly from Expansify well plates, while adherent cells can be recovered using conventional washing and dissociation approaches with appropriate enzymatic or non-enzymatic reagents.

Gigacell™ is being developed to support cell harvest through its closed, format-specific fluid-handling configuration, extending the same general recovery principles used with smaller Expansify™ formats to larger-scale culture.

Harvest conditions should be selected and optimized for the specific cell type and application. Expansify™ well plates are designed to integrate with standard laboratory cell-recovery workflows without requiring specialized harvest equipment.

13. How can harvest conditions affect cell viability?

Post-harvest cell viability depends on both the physiological state of the culture at the time of harvest and the cell-recovery method used. Factors that can reduce viability include excessive mechanical stress, prolonged or overly harsh dissociation, extended culture beyond an appropriate harvest point, and nutrient depletion or metabolite accumulation before harvest.

The sensitivity of cells to these conditions varies by cell type and application. Cell viability and recovery should therefore be assessed after harvest and established for the selected harvest method and downstream process.

14. How do I scale from a 24-Well Plate well to a 1-Well Plate?

The Expansify 24-Well Plate and 1-Well Plate use the same core HDCR culture architecture, allowing initial scale-up conditions to be translated using culture area as a common basis. For adherent cell workflows, maintaining the same seeding density in cells/cm² provides a practical starting point for transferring a culture between formats.

Example: Scaling from the Expansify 24-Well Plate to the 1-Well Plate

A. Determine the device scaling factor

• Expansify 24-Well Plate growth area: 2 cm² per well
• Expansify 1-Well Plate growth area: 70 cm²
• Scaling factor: 70 ÷ 2 = 35

B. Determine the equivalent seeding target density

• If a 24-Well culture is seeded with 50,000 cells per well, the effective seeding density is:

• 50,000 cells ÷ 2 cm² = 25,000 cells/cm²
• Applying the same seeding density to the Expansify 1-Well Plate:
• 25,000 cells/cm² × 70 cm² = 1.75 million cells
• Both culture formats are now seeded at the same cell density relative to available growth area.

C. Determine medium volumes and feeding requirements

• Medium volume, feeding strategy, and harvest timing should not be scaled solely by this 35-fold factor. These parameters should be established based on cell number, growth kinetics, nutrient consumption, metabolic demand, and the recommended working volume for each format.

1. What is the best way to ensure a successful first experiment using Expansify?  

For a first Expansify cell culture experiment, review the Expansify Quick Start Guide and applicable how-to resources, available at www.xdemics.com, before beginning the study. Successful culture initiation and expansion depend on appropriate device preparation, cell handling, medium management, and harvest conditions.

Key considerations include ensuring that the culture surface is properly wetted and free of trapped air that could interfere with the cell-expansion niches, monitoring cell growth and medium requirements as culture density increases, and using harvest conditions appropriate for the cell type and Expansify format. Gentle cell-handling practices, including the use of wide-bore pipette tips for concentrated cultures when appropriate, can also help reduce pipetting-associated mechanical stress.

For application-specific guidance, contact XDemics Support before initiating a new workflow.

2. What is the best way to evaluate whether Expansify is right for my process?

The suitability of Expansify™ should be evaluated in the context of the specific cell type, process objectives, scale requirements, target cell yield, and relevant performance endpoints. An effective evaluation typically compares culture performance in Expansify™ with an established reference process under conditions that are relevant to the intended application.

Existing process parameters can be used as a starting point to facilitate meaningful comparison while identifying any Expansify™-specific optimization requirements. Depending on the application, evaluation may include technical consultation, workflow review, and a pilot study to assess cell growth, viability, yield, productivity, or other process-specific outcomes.

This approach can provide data to inform process optimization, cell culture scale-up, and selection of the most appropriate Expansify™ format.

Contact XDemics Support with your cell type, current culture vessel, target yield, and principal evaluation endpoints.  

3. How are Expansify culture plates supplied and can they be reused?

Expansify RUO cultureware products are single-use only and are individually packaged and provided as ethylene oxide (EO)-treated products, available in packs of one or ten plates.

4. Does Expansify affect cell phenotype or differentiation potential?

Cell phenotype is influenced by numerous factors, including media composition, culture duration, oxygen availability, substrate interactions, and cell density. In the studies and cell types evaluated, cells cultured in Expansify maintained the expected phenotypic markers, functional characteristics, and differentiation potential during extended culture.

Representative examples are available in the Application Notes & Protocols section of XDemics’ website, including long-term culture studies in which cells retained their expected biological properties throughout expansion. As with any culture system, phenotype and function should be confirmed using application- and cell-specific assays.

5.  What cells / biological products have been successfully cultured or produced in Expansify systems?

Expansify has been evaluated across a broad range of cell types, cell culture workflows, and biological production applications, including:

• Immortalized suspension cells: ExpiCHO, CHO-K1, Expi293PRO, K-562, Jurkat, VPC 2.0, SF9
• Immortalized adherent cells: HEK293T, A549, HeLa, Vero, BHK-21, U2OS, PC3, Huh7.5, L929
• Biologics: antibody stable cell line development (single-cell expansion), screening and mAb production from stable CHO-K1 cell lines
• Immune cells: T cells (primary human and engineered CAR-T)
• Stem and progenitor cells: iPSC-derived neural progenitor cells, human and canine mesenchymal stem cells (MSCs)
• Primary cells: human dermal fibroblasts (microcarrier-assisted culture)
• Viral vectors and virus production: AAVs, oncolytic viruses

6. Can Expansify support low-density culture and single-cell cloning studies?

Yes. Expansify can support low-density seeding and clonal expansion workflows.

Many users have adopted Expansify into their cell line development (CLD) workflows. The platform's efficient gas exchange and available growth surface area provide a supportive environment for single-cell outgrowth and colony formation. Imaging and colony-tracking approaches may be adapted according to the requirements of the specific workflow.

7. Why do cells appear less confluent immediately after seeding than in conventional cultureware?

In conventional cultureware, cells are distributed across a single flat surface and therefore appear visually dense shortly after seeding.  In Expansify, cells distribute across a substantially larger available growth area and throughout the culture environment. As a result, cultures may often appear less confluent immediately after seeding despite being seeded at an equivalent or higher density. This visual difference reflects cell distribution rather than reduced cell number. Visual confluence in a single focal plane may not directly represent total culture density in Expansify.

8. Can cells be seeded into Expansify immediately after thawing?

Many cell types can be thawed and seeded directly into Expansify culture systems using standard post-thaw handling procedures.  Unlike some workflows that incorporate a recovery phase in conventional flasks prior to expansion, direct seeding into Expansify may be appropriate when supported by a cell-specific protocol. Post-thaw viability and recovery should be assessed using appropriate cell-specific methods. 

9. Why does cell morphology sometimes differ from what is observed in conventional cultureware?

Cell morphology is strongly influenced by the physical environment in which cells grow. Many cells initially exhibit morphologies similar to those observed on conventional tissue culture-treated plastic. As cultures expand, however, cells frequently transition from predominantly two-dimensional growth into more complex multicellular arrangements. Depending on the cell type, cultures may adopt two-and-a-half-dimensional or fully three-dimensional growth patterns.

In addition, the silicone surfaces used in Expansify are inherently ultra-low attachment (hydrophobic) unless coated with extracellular matrix (ECM) proteins. Consequently, some adherent cell types may form aggregates or spheroid-like structures in the absence of ECM coating. Morphology alone does not establish cell identity, phenotype, or function. Confirm the relevant characteristics using cell-specific assays after expansion and dissociation.