Microchip-based 3D-cell culture using polymer nanofibers generated by solution blow spinning

Abstract

Polymer nano/micro fibers have found many applications including 3D cell culture and the creation of wound dressings. The fibers can be produced by a variety of techniques that include electrospinning, the primary disadvantage of which include the requirement for a high voltage supply (which may cause issues such as polymer denaturation) and lack of portability. More recently, solution blow spinning, where a high velocity sheath gas is used instead of high voltage, has been used to generate polymer fibers. In this work, we used blow spinning to create nano/microfibers for microchip-based 3D cell culture. First, we thoroughly investigated fiber generation from a 3D printed gas sheath device using two polymers that are amenable to cell culture (polycaprolactone, PCL and polystyrene, PS) as well as the parameters that can affect PCL and PS fiber quality. Using the 3D printed sheath device, it was found that the pressure of the sheath N2 and the concentration of polymer solutions determine if fibers can be produced as well as the resulting fiber morphology. In addition, we showed how these fibers can be used for 3D cell culture by directly depositing PCL fibers in petri dishes and well plates. It is shown the fibers have good compatibility with RAW 264.7 macrophages and the PCL fiber scaffold can be as thick as 178 ± 14 μm. PCL fibers created from solution blow spinning (with the 3D printed sheath device) were then integrated with a microfluidic device for the first time to fabricate a 3D cell culture scaffold with a flow component. After culturing and stimulating macrophages on the fluidic device, it was found that the integrated 3D fibrous scaffold is a better mimic of the extracellular matrix (as opposed to a flat, 2D substrate), with enhanced nitrite accumulation (product of nitric oxide release) from macrophages stimulated with lipopolysaccharide. PS fibers were also made and integrated in a microfluidic device for 3D culture of endothelial cells, which stayed viable for at least 72 hours (48 hours under the flowing conditions). This approach will be useful for future studies involving more realistic microchip-based culture models for studying cell-to-cell communication.

Use of 3D printing and modular microfluidics to integrate cell culture, injections and electrochemical analysis

“…The use of fibrous inserts serves to create a 3-D cell culture mimicking the in vivo environment more accurately. 25, 56 Two-dimensional cell cultures do not take the natural 3D environment of the cells adequately into account and often issues arise with the growth media and cell expansion. 27, 57 Cell cultures created within a scaffold are more relevant to cell models and can better simulate the living organism along with the integration to flow.…”

“…In this module, electrospun fibers were incorporated as a 3-D endothelial cell culture scaffold. 25 While most endothelial cell studies are conducted with 2-D cell cultures due to its inexpensive and well-established protocol, issues with the growth media and expansion of cells do pose some limitations. Three-dimensional cell cultures, on the other hand, demonstrate the in vivo microenvironment more holistically and can be integrated to different flow regimes.…”

Review of 3D cell culture with analysis in microfluidic systems

“…Neural stem cells could be imaged on aligned bers, while simultaneously applying a chemical gradient to determine that the cell philapodia respond to a greater extent to the chemical gradient than the alignment of the bers. 94 More recently Chen et al explored ways to incorporate ber scaffolds into a 3D printed microuidic system, 24,95,96 starting with an electrospinning approach to directly coat the inside of a channel with polycaprolactone bers. 95 Since this device was 3D printed in a hard plastic, printed threads could be included to host standard ttings making it easy to connect tubing to the device.…”

“…This same group has also reported a blow spinning set up that produced ber scaffolds on an insert that could be tted into a 3D printed ow channel. 96 Chen et al reported a second technique utilizing electrospinning that used a removable insert covered in bers (Fig. 11).…”

A step toward engineering thick tissues: Distributing microfibers within 3D printed frames

“…The flexibility and speed of airbrushing allow for nearly seamless integration with 3D printing technologies (Behrens et al, ; Chen, Townsend, Sell, & Martin, ). 3D printing has emerged as a means to rapidly create centimeter‐scaled tissue scaffolds with customizable shape and structure (Chia, ; Hutmacher Dietmar et al, ).…”