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.