Expert Guide to Extracellular Matrices

In this roundtable article with experts from four leading companies, we explore the importance of extracellular matrices (ECMs) in mimicking the cellular microenvironment. While ECMs are frequently thought of as a physical scaffold keeping cells and tissues in place, their role goes well beyond supporting cellular architecture. They provide a signaling platform in which surface molecules like integrins connect the cell’s internal framework to its surroundings, orchestrating essential communication that impacts cell growth, structure, attachment, and fate.

Selecting the right ECM for the cell type is essential. Well-matched ECMs support key assays and can be used with various cell types. However, when the chosen matrix doesn’t fit the biological context, issues with cell attachment, growth, and differentiation can arise. Addressing these challenges means understanding the native cell niche and identifying just the right mix of components to optimize cell culture outcomes.

Below, our experts share ECM selection strategies, discuss vexing challenges and solutions, weigh in on the synthetic vs natural debate, and describe the ECM technical support their companies provide.

Our panel includes Karina Durlacher-Betzer, Ph.D., Cell and Human Protein Biology R&D Department Head at MilliporeSigma, the U.S. and Canada Life Science business of Merck KGaA, Darmstadt, Germany; John Huang, Ph.D., Founder and CEO of TheWell Bioscience; Hilary Sherman, Senior Scientist at Corning; and Changsuk Moon, Ph.D., Senior Scientist, Microphysiological Systems, ATCC, and Abhay Andar, Ph.D., Lead Scientist, Microphysiological Systems, ATCC.

Biocompare: List three factors to consider when selecting an extracellular matrix

Dr. Durlacher-Betzer:

1. Cell type and application: The choice depends on the type of cells used for the assay and its final application. For example, stem cells or induced pluripotent stem cells for tissue engineering or regenerative medicine.

2. Biochemical composition: The ECM should contain specific proteins and growth factors that can influence cell behavior, including adhesion, proliferation, and differentiation.

3. Mechanical properties: The stiffness, elasticity, and overall mechanical characteristics of the ECM are crucial for mimicking the native tissue environment, affecting how cells interact with the matrix and can influence cellular functions and tissue development.

Dr. Huang:

1. Functional microenvironment: The ECM should provide the right biochemical and mechanical cues to support cell–matrix and cell–cell interactions, allowing cells to grow, differentiate, and behave physiologically. A well-defined matrix is key to building accurate 3D models.

2. Batch-to-batch consistency: Consistency is essential for reproducibility and data accuracy. Variations in ECM composition can cause large differences in experimental outcomes, especially in drug screening or long-term culture.

3. Ease of use and automation compatibility: The ECM should be easy to handle, with straightforward preparation and minimal temperature sensitivity, to reduce user error. It should also support automation for high-throughput research.

Biocompare: List three factors to consider when selecting an ECM supplier

Sherman:

1. The ability to lot reserve to ensure supply of product that has been confirmed to work in your application.

2. Accurate quantification of protein concentration to ensure experiment to experiment consistency. An example would be the Lowry method. Some suppliers use protein quantification methods that overestimate protein concentration.

3. Availability of resources such as protocols, troubleshooting guides, applications notes, and scientists to support technical questions and troubleshooting since applications that involve ECMs tend to be more complex. It’s nice to have an expert you can reach out to for additional support.

Biocompare: Provide a few expert tips and best practices on how to avoid problems with extracellular matrices.

Dr. Durlacher-Betzer:

1. Prepare and study the cell lines being used as thoroughly as possible. Review protocols, conduct a literature search, and examine product specifications and recommendations. Only well-planned assays will help avoid future problems.

2. Select an ECM that closely resembles the biochemical and physical properties of the target tissue, ensuring that the mechanical properties of the ECM align with those of the target tissue. Evaluate how cells interact with the chosen ECM to optimize performance in terms of adhesion, proliferation, and differentiation, which will facilitate achieving the desired outcomes in tissue engineering applications.

3. Consider that ECM Gel is a temperature-sensitive product. Elevated temperatures can cause the gel to polymerize and solidify rapidly, typically within 5–10 minutes. To avoid this issue, ECM Gel should be thawed overnight at 2-8 °C, and it is crucial to store it on ice during use.

Dr. Huang:

1. Maintain consistency and care throughout the preparation process to ensure reliable results. Start by preparing a uniform, bubble-free cell suspension and mix gently with the matrix to achieve even cell distribution. Control the gelation time and transfer speed to prevent uneven setting or premature solidification.

2. Maintaining consistent seeding density, using compatible media, and following standardized handling protocols all help reduce variability and improve reproducibility.

3. Harvesting or dissociating cells should be done carefully with appropriate reagents to preserve cell viability and structural integrity for downstream analysis.

Sherman:

1. Anything that will encounter temperature-sensitive ECMs should be pre-chilled to prevent premature polymerization or protein loss from binding to things like tips and tubes.

2. Normalize for protein concentration since ECMs are animal-derived products they come bottled at different concentrations. Setting up assays by protein concentration instead of percent dilution will help to achieve better assay to assay consistency.

Drs. Moon and Andar:

Working with ECMs in cell culture can be challenging due to their temperature sensitivity, adhesive nature, and variability. The following best practices help ensure reproducibility and minimize technical issues.

1. Maintain temperature control

     a. Thaw temperature-sensitive ECMs gradually at 4°C or on ice to prevent premature gelation.

     b. Keep ECM solutions and pipette tips chilled during preparation.

2. Prevent degradation and variability

     a. Aliquot ECMs into single-use vials to avoid repeated freeze–thaw cycles.

     b. Aim for low lot-to-lot variability, which is easier to achieve with synthetic ECMs.

3. Optimize pipetting technique

     a. Use wide-bore, low-retention tips and pipette slowly with gentle up-and-down motions.

     b. Employ reverse pipetting to reduce bubble formation and ensure accurate delivery.

     c. After mixing cells with ECM, let the mixture rest on ice for 5–10 minutes before loading.

4. Ensure correct concentration and handling

     a. Verify protein concentration for 3D architecture stability; insufficient concentration can lead to matrix contraction or collapse.

     b. For collagen polymerization, check and adjust pH using indicator paper before starting.

5. Preserve structural integrity

     a. When forming dome-shaped 3D structures, use prewarmed, non-cell-treated plasticware and allow domes to harden before adding media.

     b. During media changes (e.g., collagen overlays), replace only 90% of the media to avoid disturbing the ECM layer.

6. Monitor cell morphology

     a. Early signs of ECM incompatibility include poor adhesion or abnormal morphology. Adjust ECM type or concentration promptly.

7. Control incubation and coating conditions

     a. Ensure proper incubation time, concentration, and temperature to avoid uneven coating or detachment.

Biocompare: How do synthetic cell matrices compare to natural matrices, and do you recommend them?

Dr. Durlacher-Betzer:

Synthetic cell matrices and natural matrices are both important in cell and organoid culture as well as stem cell research, yet they have distinct characteristics. Natural matrices consist of biomaterials like collagen, gelatin, and fibrin derived from biological sources, closely resembling the extracellular matrix found in tissues. These matrices provide natural biochemical signals that facilitate cell adhesion, growth, and differentiation. In contrast, synthetic matrices are made from engineered polymers such as polyethylene glycol (PEG), polylactic acid (PLA), and polycaprolactone (PCL). While synthetic matrices can be tailored for specific mechanical properties and degradation rates, they lack the biological cues found in natural matrices.

Natural matrices are generally biocompatible and biodegradable, promoting natural cellular responses and supporting tissue regeneration, though by their nature they can exhibit batch-to-batch variability. Synthetic matrices offer greater customizability, allowing precise control over properties like stiffness and porosity. They also tend to be more stable, reducing variability in performance. In terms of applications, natural matrices are ideal for biological interactions, such as in wound healing and organoid cultures. Meanwhile, synthetic matrices are better suited for applications that require specific mechanical properties or controlled degradation, such as drug delivery systems and certain tissue engineering scenarios.

Natural matrices are recommended for applications that require a biological environment, particularly in regenerative medicine, where cell behavior is influenced by extracellular matrix components. In contrast, synthetic matrices are preferable when precise control over physical properties is essential, as well as in situations where scalability and reproducibility are critical. Ultimately, the choice of matrix depends on the specific requirements of the intended application.

Sherman:

Synthetic matrices are an ideal choice if you need a more defined system without the variability and unknowns that can come with a natural ECM. Unfortunately, synthetic EMCs do not currently replicate all the functions of natural ECMs, so they are better suited if you fully understand the biology of the system you are modeling and can supplement missing biological components or if you just need a scaffold for your model.

Drs. Moon and Andar:

Synthetic matrices are non-biological materials made from biocompatible polymers and offer high reproducibility, tunability, and reduced batch variability, making them ideal for applications that require consistency and scalability, such as drug screening and clinical translation. They allow precise control over matrix properties and are well-suited for mechanistic studies and standardized assays.

Natural matrices, on the other hand, provide rich biochemical cues that closely mimic native tissue environments, supporting cell viability, differentiation, and functional maturation. This makes them highly valuable for exploratory or developmental work, especially with sensitive cell types like primary cells or stem cells. However, they can suffer from variability and undefined components.

Recommendations:

• For experiments requiring consistency, scalability, and regulatory compliance, synthetic matrices are preferred.
• For studies aiming to replicate complex in vivo conditions or involving sensitive cell types, natural matrices remain the better choice.

Biocompare: What technical support, protocols, or scientific data do you provide to help researchers optimize experimental outcomes with your matrices?

Dr. Durlacher-Betzer:

MilliporeSigma provides extensive technical support, protocols, and scientific data to help researchers optimize experimental outcomes with their extracellular matrices. We offer comprehensive technical documentation, including detailed protocols for the use of their ECM products and experimental data. This includes guidelines for cell culture techniques, troubleshooting tips, and application notes.

Additionally, we provide access to various scientific publications and studies that detail the properties, applications, and performance of their ECM products. This literature helps researchers learn how to effectively utilize ECMs in their experiments.

Furthermore, we offer dedicated customer support to address technical inquiries and provide guidance on the use of their products. This support is beneficial for researchers needing assistance with specific experimental designs or troubleshooting.

Dr. Huang:

At TheWell Bioscience, we are highly committed to providing comprehensive technical and scientific support to ensure every researcher can achieve the best results. Each customer receives dedicated technical support from our experienced scientific team, offering personalized guidance from experimental design through troubleshooting and optimization.

We also provide a wide range of scientific resources, including detailed protocols, white papers, application notes, and case studies, all available online to support various 3D culture applications. Our growing library of video tutorials and webinars showcases practical workflows and advanced uses across organoid, stem cell, co-culture, invasion, and in vivo studies.

In addition, the VitroGel^® platform is well supported by a strong body of scientific validation, with hundreds of peer-reviewed publications demonstrating its reproducibility and versatility across diverse research fields. Together, these resources create a robust support ecosystem that empowers scientists to accelerate discovery and innovation with confidence.

Sherman:

Corning has more technical resources available than any other supplier of ECMs. We offer protocols, detailed whitepapers on popular applications, FAQs and more. Additionally, our scientific support team is well experienced in working with ECMs to support our customers with their unique questions and applications.

Drs. Moon and Andar:

ATCC provides extensive technical resources and scientific support to ensure successful use of ATCC Cell Basement Membrane (ATCC^® ACS-3035™) across advanced cell culture applications. Researchers receive:

• Detailed protocols and technical sheets with step-by-step instructions for coating, seeding, and culture, tailored for sensitive and complex cell systems.
• Application-specific guidance, including best practices for 3D organoid culture, tumorsphere formation, hepatocyte sandwich cultures, and feeder-free stem cell systems.
• Validated experimental data demonstrating compatibility with organoids derived from primary tissues, iPSC-derived models, patient-derived organoids, and neural differentiation workflows.
• Direct access to scientific support from experts experienced in ECM optimization for diverse cell types and advanced in vitro models.
• Additional resources for specialized applications such as angiogenesis modeling (tube formation assays) and differentiation of iPSC-derived neural progenitor cells and neurons.