Researchers grow cells in ‘paper organs’ through 3D Printing
Usually, scientists test new medicines in animal test model or people, they study the effects of the drugs on cells growing in Petri dishes. However, a 2D layer of cells is a poor alternative for the much more complex 3D structure of tissues in organs.
In the latest research published in ACS journal Nano Letters, researchers have used a 3D printer to make paper organs, along with artificial blood vessels, that they can populate with cells.
In the body, tissues with similar functions grouped together in organs, such as the brain, heart or stomach. Organs also possess supporting cells, including nerves, blood vessels and connective tissues. An organ’s 3D architecture provides biological, structural and mechanical support to cells that influence their growth and response to external stimuli, such as medicines.
Yu Shrike Zhang with his collaborative team wanted to see whether they could combine 3D printing and bacterial cellulose to make supports for artificial organs that they could then fill with cells. Cellulose, a complex carbohydrate made by plants, algae and some bacteria, is a low-cost material used to make paper.
Why bacterial cellulose
Bacterial cellulose carries a series of attractive features like natural origin, moderate biosynthetic process, good biocompatibility, and cost-effectiveness. Moreover, bacterial cellulose nanofibers can be easily processed into 3D intertwined structures and form stable paper devices after simple drying. These advantages make it an ideal material for the development of organ-on-a-chip devices using matrix-assisted sacrificial 3D printing.
Breast tumor model
Researchers created a breast tumor model with 3D printed petroleum jelly-paraffin ink into a bacterial cellulose hydrogel. In order to make it porous and paper-like, they air-dried the hydrogel. When they heated the ink, it liquefied and was easy to remove, leaving behind hollow microchannels. The team wet the paper “organ” and added endothelial cells — the cell type that lines blood vessels — to the microchannels and added breast cancer cells to the rest of the structure.
Dried paper organs can be stored for extended periods of time and this device can be rapidly rehydrated to produce inexpensive tissue models, which could be useful for drug screening and personalized medicine, the researchers say.