Tag Archives: 3D printed bioink

Printing and growing lung tissue from mucus-based bioink?

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I’m always surprised by the uses scientists can find for mucus. This time, it’s being used as the based for growing lung tissue as this July 30,2024 news item on phys.org announced, Note: A link has been removed,

Lung diseases kill millions of people around the world each year. Treatment options are limited, and animal models for studying these illnesses and experimental medications are inadequate. Now, writing in ACS Applied Bio Materials, researchers describe their success in creating a mucus-based bioink for 3D printing lung tissue. This advancement could one day help study and treat chronic lung conditions.

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Caption: Researchers developed a mucus-based bioink for 3D-printed lung tissue. Credit: Adapted from ACS Applied Bio Materials 2024, DOI:10.1021/acsabm.4c00579

A July 30, 2024 American Chemical Society (ACS) press release (also on EurekAlert), which originated the news item, delves further into the topics of lung disease, medication testing, and the importance of lung tissue,

While some people with lung diseases receive transplants, donor organs remain in short supply. As an alternative, medications and other treatments can be used to manage symptoms, but no cure is available for disorders such as chronic obstructive pulmonary disease and cystic fibrosis. Researchers continue to seek better medications, often relying on testing in rodents. But these animal models may only partially capture the complexities of pulmonary diseases in humans, and they might not accurately predict the safety and efficacy of new drugs. Meanwhile, bioengineers are exploring the production of lung tissue in the lab, either as a more accurate model to study human lungs or as a potential material to use in implants. One technique involves 3D printing structures that mimic human tissue, but designing a suitable bioink to support cell growth remains challenging. So, Ashok Raichur and colleagues set out to overcome this obstacle.

The team began with mucin, a mucus component that hasn’t been widely explored for bioprinting. Segments of this antibacterial polymer’s molecular structure resemble epidermal growth factor, a protein that promotes cell attachment and growth. Raichur and colleagues reacted mucin with methacrylic anhydride to form methacrylated mucin (MuMA), which they then mixed with lung cells. Hyaluronic acid — a natural polymer found in connective and other tissues — was added to increase the bioink’s viscosity and enhance cell growth and adhesion to MuMA. After the ink was printed in test patterns including round and square grids, it was exposed to blue light to crosslink the MuMA molecules. The crosslink bonds stabilized the printed structure in the form of a porous gel that readily absorbed water to support cell survival.

The researchers found that the interconnected pores in the gel facilitated diffusion of nutrients and oxygen, encouraging cell growth and formation of lung tissue. The printed structures were nontoxic and slowly biodegraded under physiological conditions, making them potentially suitable as implants in which the printed scaffold would gradually be replaced by newly grown lung tissue. The bioink could also be used to make 3D models of lungs to study lung disease processes and evaluate potential treatments.

The authors acknowledge funding from the Government of India’s Department of Science and Technology.

Here’s a link to and a citation for the paper,

3D Bioprinting with Visible Light Cross-Linkable Mucin-Hyaluronic Acid Composite Bioink for Lung Tissue Engineering by Sruthi C. Sasikumar, Upashi Goswami, Ashok M. Raichur. ACS Appl. Bio Mater. 2024, 7, 8, 5411–5422 DOI: https://doi.org/10.1021/acsabm.4c00579 Published July 12, 2024 Copyright © 2024 American Chemical Society

This paper is behind a paywall.

Programmable living materials made with 3D printing methods and synthetic biology

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There’s more than one ‘living’ material story here on this blog; it’s the plant cells that make this latest story different from the others. From a May 1, 2024 news item on phys.org, Note: A link has been removed,

Scientists are harnessing cells to make new types of materials that can grow, repair themselves and even respond to their environment. These solid “engineered living materials” are made by embedding cells in an inanimate matrix that’s formed in a desired shape. Now, researchers report in ACS Central Science that they have 3D printed a bioink containing plant cells that were then genetically modified, producing programmable materials. Applications could someday include biomanufacturing and sustainable construction.

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Caption: After 24 days, the colors produced by plant cells in two different bioinks printed in this leaf-shaped engineered living material are clearly visible. Credit: Adapted from ACS Central Science 2024, DOI: 10.1021/acscentsci.4c00338

A May 1, 2024 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, explains what makes this living material different,

Recently, researchers have been developing engineered living materials, primarily relying on bacterial and fungal cells as the live component. But the unique features of plant cells have stirred enthusiasm for their use in engineered plant living materials (EPLMs). However, the plant cell-based materials created to date have had fairly simple structures and limited functionality. Ziyi Yu, Zhengao Di and colleagues wanted to change that by making intricately shaped EPLMs containing genetically engineered plant cells with customizable behaviors and capabilities.

The researchers mixed tobacco plant cells with gelatin and hydrogel microparticles that contained Agrobacterium tumefaciens, a bacterium commonly used to transfer DNA segments into plant genomes. This bioink mixture was then 3D printed on a flat plate or inside a container filled with another gel to form shapes such as grids, snowflakes, leaves and spirals. Next, the hydrogel in the printed materials was cured with blue light, hardening the structures. During the ensuing 48 hours, the bacteria in the EPLMs transferred DNA to the growing tobacco cells. The materials were then washed with antibiotics to kill the bacteria. In the following weeks, as the plant cells grew and replicated in the EPLMs, they began producing proteins dictated by the transferred DNA.

In this proof-of-concept study, the transferred DNA enabled the tobacco plant cells to produce green fluorescent proteins or betalains — red or yellow plant pigments that are valued as natural colorants and dietary supplements. By printing a leaf-shaped EPLM with two different bioinks — one that created red pigment along the veins and the other a yellow pigment in the rest of the leaf — the researchers showed that their technique could produce complex, spatially controlled and multifunctional structures. Such EPLMs, which combine the traits of living organisms with the stability and durability of non-living substances, could find use as cellular factories to churn out plant metabolites or pharmaceutical proteins, or even in sustainable construction applications, according to the researchers.

The authors acknowledge funding from National Key Research and Development Program of China, the National Natural Science Foundation of China, the Natural Science Foundation of Jiangsu Province, and the State Key Laboratory of Materials-Oriented Chemical Engineering.

Here’s a link to and a citation for the paper,

Advancing Engineered Plant Living Materials through Tobacco BY-2 Cell Growth and Transfection within Tailored Granular Hydrogel Scaffolds by Yujie Wang, Zhengao Di, Minglang Qin, Shenming Qu, Wenbo Zhong, Lingfeng Yuan, Jing Zhang, Julian M. Hibberd, and Ziyi Yu. ACS Cent. Sci. 2024, 10, 5, 1094–1104 DOI: https://doi.org/10.1021/acscentsci.4c00338 Publication Date:May 1, 2024 Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.

This paper is open access.

I think the last three years in particular have seen an upsurge of living materials stories (on this blog, at least). This one is a favourite of mine,

If you’re curious to see more, I suggest using the search term ‘living materials’.