Caroline Augspurger

Microbioreactor design for 3-D cell cultivation to create a pharmacological screening system

A biocompatible cell culture environment that enables continued existence of three dimensionally aggregated cells in a polycarbonate‐based scaffold structure was developed. A micro structured polymeric scaffold allows perfusion of cells due to a microporous structure generated by ion track etching and micro thermoforming. Biocompatibility and sterilizability was approved for the whole system. As oxygenation and mass transport within a closed system is most relevant for 3‐D cell culture, two approaches of pumping systems were tested. The human hepatocarcinoma cell line HepG2 was used to examine basic cytological parameters in response to the enviroment. Our data indicate that an actively perfused 3‐D cell culture induces a more differentiated phenotype in HepG2 cells than the 2‐D setup. Thus, our results provide further support to the theory that 3‐D‐cultivated cells display a non‐proliferative behavior. In this respect, 3‐D cultures resemble in vivo conditions more closely. Microreactors are widely applied for organic syntheses, but can also be used for screening applications in drug discovery and medical research. The bioreactor versions presented here were equipped with active fluidic components.

In vitro cultivation of biopsy derived primary hepatocytes leads to a more metabolic genotype in perfused 3D scaffolds than static 3D cell culture

The development of reliable systems for testing new compounds for use in the pharmaceutical industry has been a challenging task to date and the concept of a 3D, organotypic cell culture is emerging as a serious alternative to traditional 2D cell cultures or animal testing. We developed a biocompatible 3D cell culture environment that enables the continued existence of cells in a polycarbonate scaffold structure optionally housed in a perfusable bioreactor system. This article focuses on scaffold-based 3D cultivation strategies of biopsy-derived primary human hepatocytes. Cells were examined for whole genome gene expression and for basic cytological parameters. Examining gene networks by Illumina Pathways Analysis revealed that genes associated with metabolic functions are predominantly upregulated under perfusion. Further, we observed individually expressed profiles, which were also reflected by basic cytological parameters such as metabolic activity, albumin production and urea synthesis. With respect to their biotransformation capability, we hypothesize that a perfused 3D culture creates better conditions for the maintenance of primary hepatocytes. For more standardizable experiments with human hepatocytes, we propose the use of a hepatocyte model immortalized by transduction procedures.