Hydrogel-coated microfluidic channels for cardiomyocyte culture.

Nasim Annabi,Mohsen Afshar Bakooshli,Šeila Selimović,Juan Pablo Acevedo Cox,Anthony S Weiss,Ali Khademhosseini,João Ribas,Donald Cropek,Déborah Heintze

doi:10.1039/c3lc50252j

Abstract

The research areas of tissue engineering and drug development have displayed increased interest in organ-on-a-chip studies, in which physiologically or pathologically relevant tissues can be engineered to test pharmaceutical candidates. Microfluidic technologies enable the control of the cellular microenvironment for these applications through the topography, size, and elastic properties of the microscale cell culture environment, while delivering nutrients and chemical cues to the cells through continuous media perfusion. Traditional materials used in the fabrication of microfluidic devices, such as poly(dimethylsiloxane) (PDMS), offer high fidelity and high feature resolution, but do not facilitate cell attachment. To overcome this challenge, we have developed a method for coating microfluidic channels inside a closed PDMS device with a cell-compatible hydrogel layer. We have synthesized photocrosslinkable gelatin and tropoelastin-based hydrogel solutions that were used to coat the surfaces under continuous flow inside 50 μm wide, straight microfluidic channels to generate a hydrogel layer on the channel walls. Our observation of primary cardiomyocytes seeded on these hydrogel layers showed preferred attachment as well as higher spontaneous beating rates on tropoelastin coatings compared to gelatin. In addition, cellular attachment, alignment and beating were stronger on 5% (w/v) than on 10% (w/v) hydrogel-coated channels. Our results demonstrate that cardiomyocytes respond favorably to the elastic, soft tropoelastin culture substrates, indicating that tropoelastin-based hydrogels may be a suitable coating choice for some organ-on-a-chip applications. We anticipate that the proposed hydrogel coating method and tropoelastin as a cell culture substrate may be useful for the generation of elastic tissues, e.g. blood vessels, using microfluidic approaches.

Highlights

IntroductionIncorporating living cells into microfabricated devices has become a focus of interest for applications in tissue engineering,[1,2,3,4] diagnostics[5,6,7] and drug screening.[8,9,10,11,12] Reducing the cell-based experimental platform from the standard well-plate devices to a microfluidic device has several advantages, including a reduction in reagent amount and experiment duration, and a cost reduction.[13,14] the number of cells required for a microfluidic experiment is significantly smaller than for a well-plate setup
In this paper we present a new method for coating microfluidic channels with photocrosslinkable hydrogels
We used recombinant human tropoelastin and gelatin extracted from bovine skin to synthesize photocrosslinkable methacrylated tropoelastin (MeTro) and GelMA gels, respectively

Summary

Introduction

Incorporating living cells into microfabricated devices has become a focus of interest for applications in tissue engineering,[1,2,3,4] diagnostics[5,6,7] and drug screening.[8,9,10,11,12] Reducing the cell-based experimental platform from the standard well-plate devices to a microfluidic device has several advantages, including a reduction in reagent amount and experiment duration, and a cost reduction.[13,14] the number of cells required for a microfluidic experiment is significantly smaller than for a well-plate setup This is especially important for studies relying on primary cells extracted from sacrificed animals. In the field of microfluidics, poly(dimethylsiloxane) (PDMS) is often the material of choice.[16] It is largely transparent to visible and UV light, permeable to air and water, but not to polar and large molecules Most importantly, it is compatible with cells when fully cured. Untreated PDMS is hydrophobic and not suitable for direct cell attach-

Methods

Results

Conclusion