Abstract
In this paper, we describe the use of 3D printed devices for both static and flow studies that contain electrospun collagen scaffolds and can accommodate transepithelial/transendothelial electrical resistance (TEER) measurements. Electrospinning was used to create the collagen scaffold, followed by an optimized 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-Hydroxysuccinimide (EDC/NHS) cross-linking procedure to produce stable collagen fibers that are similar in size to fibers in vivo. LC/MS was used to study the leaching of solvent and NHS from the scaffold, with several rinsing steps being shown to eliminate the leaching and promote the culture of Madin-Darby Canine Kidney (MDCK) epithelial cells on the scaffold. Both static and flow 2-part devices were successfully fabricated by 3D printing using either VeroClear or MED610 material (PolyJet printing) and assembling the scaffold between laser cut Teflon gaskets. The devices were designed to easily accommodate commonly used STX2 chopstick electrodes for TEER measurements. A detailed comparison was made between the use of collagen scaffolds vs other electrospun materials for cell culture. The collagen extracellular matrix model displayed a high barrier functionality for up to 7 days. In addition, a different 3D printed device with a collagen scaffold is described to incorporate continuous flow and replenishment of media under the cell layer in a manner that also enables periodic recording of TEER measurements. Overall, this work shows that the combination of biological ECM materials such as collagen into microfluidic devices that incorporate flow have great potential to form more realistic cell culture models in areas such as blood brain barrier research.