3D bioprinting for lungs and hollow organs

Bioengineered 3D Models to Recapitulate Tissue Fibrosis

Fibrosis, characterized by progressive tissue stiffening resulting in organ failure, is a growing health problem affecting millions of people worldwide. Currently, therapeutic options for tissue fibrosis are severely limited and organ transplantation is the only effective treatment for the end-stage fibrotic diseases with inherent limitations. Recent advancements in engineered 3D in vitro human disease mimic models, recapitulating the tissue pathophysiology, have provided unique state-of-the-art platforms for: (i) understanding the biological mechanisms involved in the disease pathogenesis; and (ii) high-throughput and reproducible drug screening. This review focuses on the recent multidisciplinary developments made towards advanced 3D biomimetic fibrotic tissue (liver, kidney, and lung) models that combine highly precision manufacturing techniques with high cellular functionality and biophysical (mechanical) properties.

Force modeling to develop a novel method for fabrication of hollow channels inside a gel structure

Fabrication of hollow channels with user-defined dimensions and patterns inside viscoelastic, gel-type materials is required for several applications, especially in biomedical engineering domain. These include objectives of obtaining vascularized tissues and enclosed or subsurface microfluidic devices. However, presently there is no suitable manufacturing technology that can create such channels and networks in a gel structure. The advent of three-dimensional bioprinting has opened new possibilities for fabricating structures with complex geometries. However, application of this technique to fabricate internal hollow channels in viscoelastic material has not been yet explored to a great extent. In this article, we present the theoretical modeling/background of a proposed manufacturing paradigm through which hollow channels can be conveniently fabricated inside a gel structure. We propose that a tip connected to a robotic arm can be moved in X-, Y-, and Z-axis as per the desired design. The tip can be moved by a magnet or mechanical force. If the tip is further trailed with porous tube and moved inside the viscoelastic material, corresponding internal channels can be fabricated. To achieve this, however, force modeling to understand the forces that will be required to move the tip inside viscoelastic material should be known and understood. Therefore, in our first attempt, we developed the computational force modeling of the tip movement inside gels with different viscoelastic properties to create the channels.