3D Printing Real Wood With Just Cellulose And Lignin

March 27, 2024 by Maya Posch 23 Comments

Although the components of wood – cellulose and lignin – are exceedingly cheap and plentiful, combining these into a wood-like structure is not straightforward, despite many attempts to make these components somehow self-assemble. A recent attempt by [MD Shajedul Hoque Thakur] and colleagues as published in Science Advances now may have come closest to 3D printing literal wood using cellulose and lignin ink, using direct ink writing (DIW) as additive manufacturing method.

Microstructures of 3D-printed wood after printing and post-printing operations. (Credit: Thakur et al., 2024) — Microstructures of 3D printed wood after printing and post-printing operations. (Credit: Thakur et al., 2024)

This water-based ink was created by mixing TOCN (tempo-oxidized cellulose nanofiber), a 10.6 wt % aqueous CNC (cellulose nanocrystals) and lignin in a 15:142:10 ratio, giving it roughly the viscosity of clay. The purpose of having both TOCNs and CNCs is to replicate the crystalline and amorphous cellulose elements of wood-based cellulose.

This ink was printed from a syringe head (SDS-60) installed in a Hyrel 3D Engine HR 3D printer. This printer is much like your average FDM printer, just targeting bioprinting and a wide range of heads to print and handle various attachments in a laboratory setting. The ink was extruded into specific shapes that were either freeze dried to get rid of the liquid component, or additionally also heated (at 180°C), with a third set of samples put into a hot press. These additional steps seem to promote the binding of the lignin and create a more durable result.

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ARPA-H Moonshot Project Aims To Enable 3D Printing Of Human Organs

October 4, 2023 by Maya Posch 9 Comments

The field of therapeutic cloning has long sought to provide a way to create replacement organs and tissues from a patient’s own cells, with the most recent boost coming from the US Advanced Research Projects Agency for Health (ARPA-H) and a large federal contract awarded to Stanford University.

Patients on the organ donation waiting list in the US (Source: HRSA)

The creatively named Health Enabling Advancements through Regenerative Tissue Printing (HEART) project entails a 26.3 million USD grant that will be used to create a functioning bioprinter backed by a bank of bioreactors. Each bioreactor will cultivate a specific type of cell, which will then be ‘printed’ in its proper place to gradually build up the target organ or tissue. The project’s five year goal is the printing of a fully functioning human heart and implanting it into a pig.

Assuming this is successful, the general procedure can then be refined to allow for testing with human patients, as well as the bioprinting of not just hearts, but also lungs, kidneys and much more. The lead investigator at Stanford University, [Mark Skylar-Scott], cautions that use with human patients is likely to be still decades off. But the lifesaving potential of this technology, once matured, is staggering. This is highlighted by data from the US HRSA, with over 42,000 transplants in 2022 in the US alone, with over a hundred-thousand patients waiting and 17 people who die each day before an organ becomes available.

3D Printing Gets Small In A Big Way

October 26, 2022 by Al Williams 8 Comments

If you have a 3D printer in your workshop, you probably fret more about how to get bigger objects out of it. However, the University of Amsterdam has a new technique that allows for fast large-scale printing with sub-micron resolution. The technique is a hybrid of photolithography and stereolithography.

One of the problems with printing with fine detail is that print times become very long. However, the new technique claims to have “acceptable production time.” Apparently, bioprinting applications are very much of interest to the technology’s first licensee. There is talk of printing, for example, a kidney scaffold in several hours or a full-sized heart scaffold in less than a day.

Another example application is the production of a chromatography instrument with 200 micron channels and 20 micron restrictions. This requires a printer capable of very fine detail. There are also applications in semiconductors and mechanical metamaterials. Of course, we always take note of photolithography processes because we use them to make PC boards and even integrated circuits. A desktop printer that could do photolithography might open up new ideas for producing electronic circuitry.

If you want to play with photolithography today, [Ben Krasnow] has some advice. Of course, there are several ways to produce PC boards, even with a garden-variety 3D printer.

Hackaday Links: June 5, 2022

June 5, 2022 by Dan Maloney 16 Comments

The big news this week comes from the world of medicine, where a woman has received a 3D-printed ear transplant. The 20-year-old woman suffered from microtia, a rare congenital deformity that left her without a pinna, the external structure of the ear. Using scans of the normal ear, doctors were able to make a 3D model of what the missing pinna should look like. Raw material for the print was taken from the vestigial ear of the patient in the form of cartilage cells, or chondrocytes. The ear was printed using a bioprinter, which is a bit like an inkjet printer. The newly printed ear was placed into a protective structure and transplanted. The operation was done in March, and the results are pretty dramatic. With a little squinting, it does look a bit like there are some printing artifacts in the ear, but we’d imagine that’s more from the protective cage that was over the ear as it healed.

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3D Printing Livers

February 21, 2022 by Al Williams 1 Comment

The University of Utrecht has a team that is successfully bioprinting “liver units” that are able to do some of the functions of a human liver and may open the door to new medical treatments. This isn’t simply printing a fake liver in a jar though, instead the technique uses optical tomography to rapidly create small structures of about 1 cc of volume in less than 20 seconds.

Apparently, one problem with printing hydrogels full of biological structures is that passing them through a nozzle tends to disturb the delicate structures. This technique uses no nozzle or layers, which makes it useful in this situation.

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Printer Uses Algae To Print Live Structures

June 8, 2021 by Al Williams 18 Comments

There’s a famous scene in the movie version of Frankenstein — but not in the book — where the doctor exclaims: “It’s alive!” We wonder if researchers at TU Delft had the same experience after printing living structures using algae. Of course, they aren’t creating life or even reanimating it. They are simply depositing living cells in artificial structures using a bio-compatible substrate. According to the paper, the living cells or bio ink can build up layers in a 3D printing fashion and the structures are “self-standing.”

There are some advantages, for example that the algae get their energy from sunlight. Of course they also have to eat, so unless you provide some snacks, your print will die off in about 3 days.

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3D Printing Skin Or Maybe A Dermal Regenerator

February 15, 2020 by Al Williams 11 Comments

In space — at least on Star Trek — no one can hear you apply a band-aid. That’s too low tech. When a Star Fleet officer gets an ouchie, the real or holographic doctor waves a dermal regenerator over the afflicted area, and new skin magically appears. Science fiction, huh? Maybe not. A group of scientists from Canada recently published a paper on a handheld instrument for depositing “skin precursor sheets” over full-thickness burns. The paper is behind a paywall and if you don’t know how to get it or don’t want to get it, you can see a video from the University of Toronto, below.

Although they use the term 3D printing, the device is more like a paint roller. Several substances merge together in the print head and lay down on the burn in broad stripes.

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