However, this model is time consuming and costly to set up, and the results may vary due to the batch-to-batch variation of the culture reagents. Currently the most commonly used long term hepatocyte model system is a pseudo 3D sandwich culture where the hepatocytes are cultured in 2D conditions between two layers of collagen 18 or collagen and Matrigel 19. Despite of these advances there is a continuous need for a cost-efficient, simple and reliable long-term 3D culture for primary human hepatocytes to assess DILI. More recent techniques in hepatocyte culture include 3D liver microtissue biochips coupled to a microfluidic device 15 and bioprinting 16, 17. In recent years several 3D hepatocyte culture and co-culture methods have been described 5, which include both non-scaffold-based methods utilizing 3D liver spheroids 6 (hanging drop liver spheroids 7, spheroids grown on ultra-low attachment microplates 8, microfluidic 3D cell culture 9, 10) and scaffold-based methods (3D hydrogels 11, polymeric hard scaffolds 12, biologic natural scaffolds 13, micropatterned surface microplates 14). Three-dimensional (3D) culture models facilitate the maintenance of a similar tissue architecture to that occurring in in vivo situation, which supports correct cell polarization and differentiation status. In addition, 2D cultured cells lack cell-extracellular matrix contact, intercellular communication and spatial heterogeneity that are essential for maintaining long-term liver structure and functions 4. 2D cultures are suitable for initial assessment of drug metabolism, however, their disadvantage lies in their short-term nature as hepatocytes dedifferentiate into nonfunctional cells within a few days in the standard culture conditions 3. Current practices to assess DILI include animal models that are expensive, non-human and ethically questionable as well as two-dimensional (2D) cultures of human hepatocytes and hepatocyte co-cultures with nonparenchymal cells that involve a complicated experiment setup 2.

To pursue drug metabolism studies an easily scalable model to study libraries of slowly metabolizing drug candidates is needed. In pharma industry, there is an urgent need for an adequate evaluation of the potential of the drug to induce drug induced liver injury (DILI) as DILI represents an important cause of morbidity and mortality 2.

Liver is the central drug-metabolizing organ and hepatotoxicity is a major cause for drug withdrawal 1. Together, our results show that SBS-generated gelatin scaffolds are a simple and efficient platform for use in vitro for drug testing applications. The SBS mats were highly cytocompatible, facilitated the induction of hepatocyte specific CYP gene expression in response to common medications, and supported the maintenance of hepatocyte differentiation and polarization status in long term cultures for more than 3 weeks. We used SBS mats as culturing substrates for human hepatocytes to create an array of 3D human liver tissue equivalents in 96-well format.

In pharma industry, there is an urgent need for adequate 3D liver tissue models that could be used in high throughput setting for drug screening and to assess drug induced liver injury. These SBS mats were shown to have three-dimensional fibrous porous structure similar to that of mammalian tissue extracellular matrix. Here we report, for the first time the successful generation of 3D thermally crosslinked preforms by using SBS from porcine gelatin. Gelatin is an excellent precursor for SBS as it is derived mainly from collagens that are abundant in natural extracellular matrices. Solution blow spinning (SBS) has recently emerged as a novel method that can produce nano- and microfiber structures suitable for tissue engineering.

Sigma aldrich fish gelatin