image: In an effort to provide an environmentally friendly and low-waste alternative, researchers at MIT have pioneered a tunable technique to generate wood-like plant material in a lab. view more
Credit: Image courtesy of Luis Fernando Velásquez-García, Ashley Beckwith, et al
Each year, the world loses about 10 million hectares of forest — an area about the size of Iceland — because of deforestation. At that rate, some scientists predict the world’s forests could disappear in 100 to 200 years.
In an effort to provide an environmentally friendly and low-waste alternative, researchers at MIT have pioneered a tunable technique to generate wood-like plant material in a lab, which could enable someone to “grow” a wooden product like a table without needing to cut down trees, process lumber, etc.
These researchers have now demonstrated that, by adjusting certain chemicals used during the growth process, they can precisely control the physical and mechanical properties of the resulting plant material, such as its stiffness and density.
They also show that, using 3D bioprinting techniques, they can grow plant material in shapes, sizes, and forms that are not found in nature and that can’t be easily produced using traditional agricultural methods.
“The idea is that you can grow these plant materials in exactly the shape that you need, so you don’t need to do any subtractive manufacturing after the fact, which reduces the amount of energy and waste. There is a lot of potential to expand this and grow three-dimensional structures,” says lead author Ashley Beckwith, a recent PhD graduate.
Though still in its early days, this research demonstrates that lab-grown plant materials can be tuned to have specific characteristics, which could someday enable researchers to grow wood products with the exact features needed for a particular application, like high strength to support the walls of a house or certain thermal properties to more efficiently heat a room, explains senior author Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories.
Joining Beckwith and Velásquez-García on the paper is Jeffrey Borenstein, a biomedical engineer and group leader at the Charles Stark Draper Laboratory. The research is published today in Materials Today.
Planting cells
To begin the process of growing plant material in the lab, the researchers first isolate cells from the leaves of young Zinnia elegans plants. The cells are cultured in liquid medium for two days, then transferred to a gel-based medium, which contains nutrients and two different hormones.
Adjusting the hormone levels at this stage in the process enables researchers to tune the physical and mechanical properties of the plant cells that grow in that nutrient-rich broth.
“In the human body, you have hormones that determine how your cells develop and how certain traits emerge. In the same way, by changing the hormone concentrations in the nutrient broth, the plant cells respond differently. Just by manipulating these tiny chemical quantities, we can elicit pretty dramatic changes in terms of the physical outcomes,” Beckwith says.
In a way, these growing plant cells behave almost like stem cells — researchers can give them cues to tell them what to become, Velásquez-García adds.
They use a 3D printer to extrude the cell culture gel solution into a specific structure in a petri dish, and let it incubate in the dark for three months. Even with this incubation period, the researchers’ process is about two orders of magnitude faster than the time it takes for a tree to grow to maturity, Velásquez-García says.
Following incubation, the resulting cell-based material is dehydrated, and then the researchers evaluate its properties.
Wood-like characteristics
They found that lower hormone levels yielded plant materials with more rounded, open cells that have lower density, while higher hormone levels led to the growth of plant materials with smaller, denser cell structures. Higher hormone levels also yielded plant material that was stiffer; the researchers were able to grow plant material with a storage modulus (stiffness) similar to that of some natural woods.
Another goal of this work is to study what is known as lignification in these lab-grown plant materials. Lignin is a polymer that is deposited in the cell walls of plants which makes them rigid and woody. They found that higher hormone levels in the growth medium causes more lignification, which would lead to plant material with more wood-like properties.
The researchers also demonstrated that, using a 3D bioprinting process, the plant material can be grown in a custom shape and size. Rather than using a mold, the process involves the use of a customizable computer-aided design file that is fed to a 3D bioprinter, which deposits the cell gel culture into a specific shape. For instance, they were able to grow plant material in the shape of a tiny evergreen tree.
Research of this kind is relatively new, Borenstein says.
“This work demonstrates the power that a technology at the interface between engineering and biology can bring to bear on an environmental challenge, leveraging advances originally developed for health care applications,” he adds.
The researchers also show that the cell cultures can survive and continue to grow for months after printing, and that using a thicker gel to produce thicker plant material structures does not impact the survival rate of the lab-grown cells.
“Amenable to customization”
“I think the real opportunity here is to be optimal with what you use and how you use it. If you want to create an object that is going to serve some purpose, there are mechanical expectations to consider. This process is really amenable to customization,” Velásquez-García says.
Now that they have demonstrated the effective tunability of this technique, the researchers want to continue experimenting so they can better understand and control cellular development. They also want to explore how other chemical and genetic factors can direct the growth of the cells.
They hope to evaluate how their method could be transferred to a new species. Zinnia plants don’t produce wood, but if this method were used to make a commercially important tree species, like pine, the process would need to be tailored to that species, Velásquez-García says.
Ultimately, he is hopeful this work can help to motivate other groups to dive into this area of research to help reduce deforestation.
“Trees and forests are an amazing tool for helping us manage climate change, so being as strategic as we can with these resources will be a societal necessity going forward,” Beckwith adds.
This research is funded, in part, by the Draper Scholars Program.
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Written by Adam Zewe, MIT News Office
Additional background
Paper: “Physical, mechanical, and microstructural characterization of novel, 3D-printable, tunable, lab-grown plant materials generated from Zinnia elegans cell cultures”
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
