Oxygenation Profiles of Human Blood, Cell Culture Medium, and Water for Perfusion of 3D-Bioprinted Tissues using the FABRICA Bioreactor Platform

Angela M Chen,Cutter Koehler,Abdulkadir Isidan,Matthew Lashmet,Jane L Sterner,Burcin Ekser,Lester Smith,Julia Walsh,Ping Li

doi:10.1038/s41598-020-64256-1

Angela M Chen, Cutter Koehler + Show 7 more

Open Access

https://doi.org/10.1038/s41598-020-64256-1

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Abstract

Persistent and saturated oxygen distribution from perfusion media (i.e., blood, or cell culture media) to cells within cell-dense, metabolically-active biofabricated tissues is required to keep them viable. Improper or poor oxygen supply to cells within the tissue bulk severely limits the tissue culturing potential of many bioreactors. We added an oxygenator module to our modular FABRICA bioreactor in order to provide stable oxygenation to biofabricated tissues during culture. In this proof of concept study of an oxygenated and perfused bioreactor, we characterized the oxygenation of water, cell culture medium, and human blood in the FABRICA as functions of augmenting vacuum (air inlet) pressure, perfusion (volumetric flow) rate, and tubing/oxygenator components. The mean oxygen levels for water and cell culture media were 27.7 ± 2.1% and 27.6 ± 4.1%, respectively. The mean oxygen level for human blood was 197.0 ± 90.0 mmHg, with near-physiologic levels achieved with low-permeability PharMed tubing alone (128.0 ± 14.0 mmHg). Hematologic values pre- and post-oxygenation, respectively were (median ± IQR): Red blood cell: 6.0 ± 0.5 (106/μL) and 6.5 ± 0.4 (106/μL); Hemoglobin: 17.5 ± 1.2 g/dL and 19.2 ± 3.0 g/dL; and Hematocrit: 56.7 ± 2.4% and 61.4 ± 7.5%. The relative stability of the hematologic parameters indicates that blood function and thus blood cell integrity were maintained throughout oxygenation. Already a versatile research tool, the now oxygenated FABRICA provides easy-to-implement, in vivo-like perfusion and stable oxygenation culture conditions in vitro semi-independently of one another, which means the bioreactor has the potential to serve as a platform for investigating the behavior of 3D tissue models (regardless of biofabrication method), performing drug toxicity-testing, and testing pharmaceutical efficacy/safety.

Highlights

MethodsWe used the previously reported FABRICA Bioreactor Platform[1] (Fig. 1), with some modifications
This study used packed RBC blood, which was more readily available
The FABRICA can be used to oxygenate water, cell culture media, and blood with ambient air

Summary

Methods

We used the previously reported FABRICA Bioreactor Platform[1] (Fig. 1), with some modifications. The FABRICA was soaked in 70–100% ethanol overnight followed by air-drying, soaked in Milli-Q water overnight, and air dried before use. The FABRICA has inlet and outlet channels integrated into the bioreactor. The channels open into the FABRICA basin, which, during tissue perfusion, is filled with medium. The sample holder/internal inlet port is situated in the center of the FABRICA basin such that oxygenated medium flows directly to the tissue construct. The internal outlet port is situated on the floor of the FABRICA basin. The channels are connected by the external inlet and outlet ports to tubing outside of the FABRICA by locks or slip tubing. The tubing is connected to a peristaltic roller pump (Ismatec Reglo ICC, Cole- Parmer, Wertheim, Germany)

Results

Discussion

Conclusion