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Chopping down trees and processing the wood isn’t the most efficient or environmentally friendly way to make furniture or building materials. Scientists at MIT have now made breakthroughs in a process that could one day let us 3D print and grow wood directly into the shape of furniture and other objects.

Wood may be a renewable resource, but we’re using it up much faster than we’re replenishing it. Deforestation is having a drastic impact on wildlife and exacerbating the effects of climate change. Since our appetite for wooden products isn’t likely to change, our methods for obtaining it will have to.

In recent years, researchers have turned to growing wood in the lab. Not trees – just the wood itself, not unlike the ongoing work into cultivating animal cells for lab-grown meat, rather than raising live animals and slaughtering them. And now, a team of MIT scientists has demonstrated a new technique that can grow wood-like plant material in the lab, allowing for easy tuning of properties like weight and strength as needed.

By combining two distinct approaches into an integrated workflow, Singapore University of Technology and Design (SUTD) researchers have developed a novel automated process for designing and fabricating customized soft robots. Their method, published in Advanced Materials Technologies, can be applied to other kinds of soft robots—allowing their mechanical properties to be tailored in an accessible manner.

Though robots are often depicted as stiff, metallic structures, an emerging class of pliable machines known as is rapidly gaining traction. Inspired by the flexible forms of living organisms, soft robots have wide applications in sensing, movement, object grasping and manipulation, among others. Yet, such robots are still mostly fabricated through manual casting techniques—limiting the complexity and geometries that can be achieved.

“Most fabrication approaches are predominantly manual due to a lack of standard tools,” said SUTD Assistant Professor Pablo Valdivia y Alvarado, who led the study. “But 3D printing or additive manufacturing is slowly coming into play as it facilitates repeatability and allows more complex designs—improving quality and performance.”

Researchers at the Department of Energy’s Oak Ridge National Laboratory have developed an upcycling approach that adds value to discarded plastics for reuse in additive manufacturing, or 3D printing. The readily adoptable, scalable method introduces a closed-loop strategy that could globally reduce plastic waste and cut carbon emissions tied to plastic production.

Results published in Science Advances detail the simple process for upcycling a commodity plastic into a more robust material compatible with industry 3D-printing methods.

The team upgraded , or ABS, a popular thermoplastic found in everyday objects ranging from auto parts to tennis balls to LEGO blocks. ABS is a popular feedstock for fused filament fabrication, or FFF, one of the most widely used 3D-printing methods. The upcycled version boasts enhanced strength, toughness and chemical resistance, making it attractive for FFF to meet new and higher performance applications not achievable with standard ABS.

To begin the process of bioprinting an organ, doctors typically start with a patient’s own cells. They take a small needle biopsy of an organ or do a minimally invasive surgical procedure that removes a small piece of tissue, “less than half the size of a postage stamp,” Atala said. “By taking this small piece of tissue, we are able to tease cells apart (and) we grow and expand the cells outside the body.”

This growth happens inside a sterile incubator or bioreactor, a pressurized stainless steel vessel that helps the cells stay fed with nutrients – called “media” – the doctors feed them every 24 hours, since cells have their own metabolism, Lewis said. Each cell type has a different media, and the incubator or bioreactor acts as an oven-like device mimicking the internal temperature and oxygenation of the human body, Atala said.

“Then we mix it with this gel, which is like a glue,” Atala said. “Every organ in your body has the cells and the glue that holds it together. Basically, that’s also called ‘extracellular matrix.’”.

“Ultrasonic frequencies are already being used in destructive procedures like laser ablation of tissues and tumours,” said Prof. Muthukumaran Packirisamy, who led the study along with Dr. Mohsen Habibi and PhD student Shervin Foroughi. “We wanted to use them to create something.”

For instance, utilizing the technique, aircraft mechanics could conceivably 3D-print repairs onto internal components, without opening the plane’s fuselage. It’s even possible that implants could be 3D printed within a patient’s body, without the need for surgery.

Besides the PDMS resin, the scientists have also successfully used DSP to print objects made of ceramic material. They now plan on experimenting with polymer-metal composites, followed by pure metal.

3D printing typically involves depositing layers of molten plastic, laser-melting powdered metal, or using UV light to harden gelatinous resin. A new technique takes yet another approach, however, by utilizing sound waves.

Developed by a team of scientists at Canada’s Concordia University, the technology is known as direct sound printing (DSP).

In the current version of the technique, a transducer is used to send focused pulses of ultrasound through the sides of a chamber, into liquid polydimethylsiloxane (PDMS) resin contained within. Doing so produces ultrasonic fields, which cause rapidly oscillating microscopic bubbles to temporarily form at specific points in the resin.

Researchers at Politecnico di Torino, BRIN in Indonesia, the Italian Institute of Technology (IIT) and University of Cagliari have recently introduced new composite hydrogel inks based on natural and environment friendly materials, which could be used to 3D print objects. These hydrogels, presented in a paper published in Sustainable Materials and Technologies, are based on acrylated-carboxymethyl cellulose (mCMC).

“We have been working on the development of new printable materials and functional devices since 2015, so in these years different areas were explored, resulting in many publications in the field of 3D ,” Ignazio Roppolo, one of the researchers who carried out the study, told TechXplore.

The first objective of the work by Roppolo and his colleagues was to develop polymeric hydrogels for 3D printing that are based on natural resources, to increase sustainability and reduce the use of standard synthetic resins. In recent years, the team has been collaborating with Dr. Athanasia Amanda Septevani, a researcher at BRIN’s Research Center for Environment and Clean Technology in Indonesia.