What Are Corning Transwell Inserts? The Lab's Multi-Tool | Corning

In today's research environment, assays are a mainstay of scientific investigations, and permeable supports play a vital role in the success of these projects. However, not all permeable inserts used in assays are created the same. While many standard cell culture plates use permeable inserts that resemble a single sheet, Corning^® Transwell^® inserts are multi-well inserts allowing for a two-chamber system that can expose cell cultures from above and below. This design allows for greater versatility.

Transwell inserts expand research options and capabilities. Here's what sets these systems apart.

Corning Transwell inserts — also called Transwell permeable supports — are brand-specific permeable inserts created by Corning. Unlike with standard cell culture plates, Transwell inserts are permeable membranes that support cell growth during a wide variety of research endeavors, such as cancer metastasis, 3D modeling of biological systems, or embryonic development.

In a Transwell insert, a membrane (polycarbonate, polytetrafluoroethylene, or polyester) is attached to a plastic casing that's supported above the cell culture plate. These inserts are coated in an extracellular matrix, such as collagen, fibronectin, or Corning Matrigel^® matrix.

With a single plate design, cells are more likely to attach to the plastic as they grow. In contrast, a Transwell insert allows cells to be exposed to cell culture media (or air) from above and below. Consequently, this design changes how cells grow and encourages cells to orient themselves as they normally would in vivo. As a result, researchers can produce more realistic models that can support and render more accurate results.

Compared to other permeable membranes, Transwell inserts have a unique self-centering hanging design that stops media from wicking between the insert and the well plate. Inserts have upper and lower compartments that are separated by a microporous membrane.

Alongside this self-centering design, Transwell inserts come in multiple sizes, making them useful for a wide range of applications. For smaller projects, investigators can use a 6-well plate, or they may use 12-well, 24-well, or 96-well plates for larger work, such as comparing drug responses in cells.

Transwell inserts can improve research efforts in several ways. From a design perspective, there are multiple openings around the ring at the top of each well making it easier for investigators to introduce new media and deliver it to the bottom of the basolateral chamber, facilitating liquid media exchanges, buffer changes, and drug additions. The openings offer more convenient management for cultures that go on for a month or longer or for ones that require daily media changes. The ease of handling these features provide decreases the risk of contamination during applications.

In addition, with the variety of membrane materials, pore sizes, and biological coatings, Transwell inserts empower investigators to choose the permeable membrane most appropriate for their specific application. The self-centering design also gives Transwell inserts an advantage over traditional supports. In fact, Transwell inserts are the most cited permeable support in scientific literature.

These permeable supports are designed to support a variety of techniques that aren't possible with other cell culture products. Investigators can rely on them for multiple applications, including:

1. Air liquid interphase: Some tissues in the human body, such as the eyes, lungs, and skin, are exposed to air on one side but not on the other. Recreating these models requires a platform that can allow one-sided air access. As a permeable support, Transwell inserts can grow that cell layer on a membrane, media can be removed from the top chamber only (exposing the tissue to air), leaving cells in the bottom layer exposed to the remaining liquid media. Using the permeable support this way mimics the cells' natural environment, signaling them to behave more like they do in vivo and promoting their full differentiation.
2. Drug transport: Permeable inserts also support drug or nutrient testing. This allows researchers to grow cell types that can recreate functional organs, such as intestines, kidneys, or skin on the membrane to study how organs absorb, metabolize, or transport drugs or food. With this application, investigators can add drugs above or below the membrane to assess and evaluate their activities.
3. Migration/Invasion: Larger-pore permeable membranes are vital to research efforts investigating the spread of cancer or the movement of immune cells to the site of an injury. In these applications, the membranes allow cells to travel from the top of the membrane toward a chemoattractant — a soluble molecule that pulls cells toward the area of highest concentration — under the membrane in the cell culture plate below.

Without a good model, investigators may struggle to get the answers they're looking for. That's where Transwell inserts come in. With more traditional cell culture tools there is only one chamber for cells to be in. Corning Transwell permeable supports create a multiple-chamber cell culture environment that is separated by a permeable membrane. These permeable membranes enable cells to polarize and form both an inside and outside layer. Additionally, depending on the pore size chosen, researchers can study molecule transport or cellular migration/invasion. Transwell inserts have played a pivotal role in wound repair, cell differentiation, cellular communication, and tumor metastasis research.

Ultimately, asking the questions, "What are Transwell inserts?" and "How does a Transwell system work?" and putting the answers to the test can lead to more successful, streamlined, animal-friendly investigations that can produce high-quality results. Learn more about how to use the Transwell system and this essential tool on Corning's website.