Tag Archives: plant cells

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

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.

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’.

‘Hotel for cells’ or minuscule artificial scaffolding units for plant tissue engineering

This is the first time I’ve seen an item about tissue engineering which concerns plant life.  An August 27, 2015 news item on Azonano describes the latest development with plant cells,

Miniscule artificial scaffolding units made from nano-fibre polymers and built to house plant cells have enabled scientists to see for the first time how individual plant cells behave and interact with each other in a three-dimensional environment.

These “hotels for cells” mimic the ‘extracellular matrix’ which cells secrete before they grow and divide to create plant tissue. [Note: Human and other cells also have extracellular matrices] This environment allows scientists to observe and image individual plant cells developing in a more natural, multi-dimensional environment than previous ‘flat’ cell cultures.

An August 26, 2015 University of Cambridge press release, which originated the news item, describes the research and mentions the pioneering technologies which made it possible,

The research team were surprised to see individual plant cells clinging to and winding around their fibrous supports; reaching past neighbouring cells to wrap themselves to the artificial scaffolding in a manner reminiscent of vines growing.

Pioneering new in vitro techniques combining recent developments in 3-D scaffold development and imaging, scientists say they observed plants cells taking on growth and structure of far greater complexity than has ever been seen of plant cells before, either in living tissue or cell culture.

“Previously, plant cells in culture had only been seen in round or oblong forms. Now, we have seen 3D cultured cells twisting and weaving around their new supports in truly remarkable ways, creating shapes we never thought possible and never seen before in any plant,” said plant scientist and co-author Raymond Wightman.

“We can use this tool to explore how a whole plant is formed and at the same time to create new materials.”

This ability for single plant cells to attach themselves by growing and spiralling around the scaffolding suggests that cells of land plants have retained the ability of their evolutionary ancestors – aquatic single-celled organisms, such as Charophyta algae – to stick themselves to inert structures.

While similar ‘nano-scaffold’ technology has long been used for mammalian cells, resulting in the advancement of tissue engineering research, this is the first time such technology has been used for plant cells – allowing scientists to glimpse in 3-D the individual cell interactions that lead to the forming of plant tissue.

The scientists say the research “defines a new suite of techniques” for exploring cell-environment interactions, allowing greater understating of fundamental plant biology that could lead to new types of biomaterials and help provide solutions to sustainable biomass growth.

“While we can peer deep inside single cells and understand their functions, when researchers study a ‘whole’ plant, as in fully formed tissue, it is too difficult to disentangle the many complex interactions between the cells, their neighbours, and their behaviour,” said Wightman.

“Until now, nobody had tried to put plant cells in an artificial fibre scaffold that replicates their natural environment and tried to observe their interactions with one or two other cells, or fibre itself,” he said.

Co-author and material scientist Dr Stoyan Smoukov suggests that a possible reason why artificial scaffolding on plant cells had never been done before was the expense of 3D nano-fibre matrices (the high costs have previously been justified in mammalian cell research due to its human medical potential).

However, Smoukov has co-discovered and recently helped commercialise a new method for producing polymer fibres for 3-D scaffolds inexpensively and in bulk. ‘Shear-spinning’ produces masses of fibre, in a technique similar to creating candy-floss in nano-scale. The researchers were able to adapt such scaffolds for use with plant cells.

This approach was combined with electron microscopy imaging technology. In fact, using time-lapse photography, the researchers have even managed to capture 4-D footage of these previously unseen cellular structures. “Such high-resolution moving images allowed us to follow internal processes in the cells as they develop into tissues,” said Smoukov, who is already working on using the methods in this plant study to research mammalian cancer cells.

Here’s an image illustrating the research,

Plant cells twisting and weaving in 3-D cultures Credit: Smoukov/Wightman

Plant cells twisting and weaving in 3-D cultures
Credit: Smoukov/Wightman

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

A 3-dimensional fibre scaffold as an investigative tool for studying the morphogenesis of isolated plant pells [cells?] by CJ Luo, Raymond Wightman, Elliot Meyerowitz, and Stoyan K. Smoukov. BMC Plant Biology 2015, 15:211 doi:10.1186/s12870-015-0581-7

This paper is open access.