Bioprinting for organ model for drug discovery
The current attempt in the translational medical research community is focusing more on complex human factors and conditions rather than relying on animal models. While the simplicity of the traditional in vitro models makes them robust and suitable for high throughput research, unfortunately, provides only little biological relevance to the complex biological tissues of the human body, which makes the technology gap between the lab models and industry/clinic adoptable models dramatically wide. Bioprinting paves the way for creating a biomimetic structure and environment that support in vivo like cell-cell and cell-matrix interactions with high-resolution vascularized tissue. Bioprinted tissue would represent powerful tools to provide physiologically relevant in vitro human organ models for drug toxicity assays and disease modelling that faithfully reproduce the key physiological aspects of the complex human. Typically, organotypic bioprinting requires a large number of cells of different types to achieve a physiologically relevant heterotypic tissue, which renders it an expensive approach for large-scale and high throughput assays. In addition, without a high-resolution vascularization that ensures long-term viability, a hypoxic environment may develop in the fabricated tissue due to the limited diffusion of cell nutrient into the core of the tissue. The integration of bioprinting and microfluidic technology provide an excellent opportunity to create miniaturized in vitro tissue models “organs-on-a-chip” that overcome these shortcomings. For example, various organotypic tissues can be simultaneously printed in a compartmentalized microfluidic chip and then connected through a vascular network (perfusion channels) to finally create multi organs on a chip “human-on-a-chip”.
It becomes generally accepted that 3D tissue models are superior and physiologically more relevant compared to the 2D countermodels. However, they are still not systematically validated for toxicity prediction. Furthermore, 3D bio-printed tissue models are not subject to the rigorous ethical issues that are required for organ implantation into humans, which makes them an attractive choice for many relevant industries [Vaidya 2015]. To enable these powerful models for high throughput drug discovery, systemic validation and standardization are required to certain their potential value.