- Transcending the Transwell -




"...the exposure to intraluminal flow plays an essential role in promoting endothelial cell differentiation and increasing BBB tightness..."

"...in contrast to the Transwell apparatus...endothelial cells grown under dynamic conditions ...develop in a monolayer fashion, thus mimicking the structural physiology of capillaries in vivo..."

Side by side comparison between dynamic versus static models
of blood–brain barrier in vitro: A permeability study

Janigro et al., 2006






Our mission at Flocel Inc. is not only to to provide high-quality products and services for in vitro 3D cell barrier culture, but also to convey -with integrity and transparency- the advantages of our DIV-BBB 2.0 system compared to other approaches --such as the Transwell.


- Stronger Barriers, Stronger Data -


DIV-BBB vs. Transwell: TEER

A comparative study between cell barriers cultured in a static flow (i.e., Transwell) and dynamic flow (i.e., DIV-BBB) environment showed that fluid flow conditions greatly influence how a cell barrier develops. Trans-endothelial electrical resistance (TEER) across the DIV-BBB culture (B) increased to values 10-fold higher than those recorded in the Transwell (A), and much closer to values observed in vivo. This is because dynamic flow causes shear stress on the apical surface of the cell, and influences cell development and function.

This concept is reiterated in the inset microscope images of the figure above: A cell culture that has been subjected to dynamic flow and physiologically-representative levels of shear stress (B) resulted in a confluent monolayer of cells expressing tight junctions. The cell barrier in under static flow (A) receives no shear stress, and instead forms a multilayer of cells with less tight junction organization.



- Higher Selective Permeability -


DIV-BBB vs. Transwell: Permeability


Owing to the stronger and more physiologically-accurate cell barrier grown under dynamic flow conditions, the DIV-BBB also presents a more stringent regulation of selective permeability. Tests conducted between cells cultured in the DIV-BBB (C) and Transwell (D) for passage of phenytoin (an epileptic drug with in vivo permeability levels of 0.0001 cm/s) showed markedly higher levels of permeability through the Transwell than the DIV-BBB, and 4-fold higher than in vivo. The stronger and more physiologically-accurate cell barriers grown under the dynamic fluid conditions of the DIV-BBB allow for more accurate testing of drug permeability and pharmacokinetics.


- What if I already own Transwell products? -


Endohm TEER Compatibility


If you would prefer to continue using your Transwell products (such as Endohm-6, Endohm-12, Endohm-24SNAP cell culture chambers or any "chopstick" electrodes), we also offer a Trans-endothelial Electrical Resistance (TEER) Measurement Unit that is compatible with these Endohm products, and much more versatile! Not only does our TEER Measurement Unit allow for frequency sweeps between 0.1 Hz and 1,000 Hz (0.1 Hz sampling resolution), it can be directed by the user to automatically sample single-frequency and frequency sweep data for an indefinite amount of time, and save this data to a .xls or .csv save file. No  more pushing a button and jotting down the TEER value every time you want to take a measurement!

To learn more about our Transwell-compatible TEER Measurement Units, click here.