The image accompanies Cari Shane’s August 4, 2021 article for Atlas Obscura’s Gastro Obscura about Andrew Pelling and his asparagus-based scaffolds for spinal cord stem cells (Note: A link has been removed),
Around 10 years ago, Pelling [Dr. Andrew Pelling at the University of Ottawa], a biophysicist, started thinking with his team about materials that could be used to reconstruct damaged or diseased human tissues. Surrounded by a rainbow of fresh fruits and vegetables at his University of Ottawa lab, Pelling and his team dismantle biological systems, mixing and matching parts, and put them back together in new and creative ways. It’s a little bit like a hacker who takes parts from a phone, a computer, and a car to build a robotic arm. Or like Mary Shelley’s Dr. Frankenstein, who built a monster out of cadavers. Except Pelling’s team has turned an apple into an ear and, most recently, a piece of asparagus into a scaffold for spinal-cord implants.
Pelling believes the future of regenerative medicine—which uses external therapies to help the body heal, the same way a cut heals by itself or a broken bone can mend without surgery—is in the supermarket produce aisle. He calls it “augmented biology,” and it’s a lot less expensive—by thousands and thousands of dollars—than implanting organs donated by humans, taken from animals, or manmade or bioengineered from animal tissue.
Decellularization as a process for implantation is fairly new, developed in the mid 1990s primarily by Doris Taylor. By washing out the genetic materials that make an apple an apple, for example, you are left with plant tissue, or a “cellulose mesh,” explains Pelling. “What we’re doing is washing out all the plant DNA, RNA proteins, all that sort of stuff that can cause immune responses, and rejection. And we’re just leaving behind the fiber in a plant—like literally the stuff that gets stuck in your teeth.”
When Pelling noticed the resemblance between a decellularized apple slice and an ear, he saw the true potential of his lab games. If he implanted the apple scaffolding into a living animal, he wondered, would it “be accepted” and vascularize? That is, would the test animal’s body glom onto the plant cells as if they weren’t a dangerous, foreign body and instead send out signals to create a blood supply, allowing the plant tissue to become a living part of the animal’s body? The answer was yes. “Suddenly, and by accident, we developed a material that has huge therapeutic and regenerative potential,” says Pelling. The apple ear does not enable hearing, and it remains in the animal-testing phase, but it may have applications for aesthetic implantation.
Soon after his breakthrough apple experiment, which was published in 2016 and earned him the moniker of “mad scientist,” Pelling shifted his focus to asparagus. The idea hit him when he was cooking. Looking at the end of a spear, he thought, “Hey, it looks like a spinal cord. What the hell? Maybe we can do something,” he says.
… Pelling implanted decellularized asparagus tissue under the skin of a lab rat. In just a few weeks, blood vessels flowed through the asparagus scaffolding; healthy cells from the animal moved into the tissue and turned the scaffold into living tissue. “The surprise here was that the body, instead of rejecting this material, it actually integrated into the material,” says Pelling. In the bioengineering world, getting that to happen has typically been a major challenge.
And then came the biggest surprise of all. Rats with severed spinal cords that had been implanted with the asparagus tissue were able to walk again, just a few weeks after implantation. …
While using asparagus tissue as scaffolding to repair spinal cords is not a “miracle cure,” says Pelling, it’s unlike the kinds of implants that have come before. Donated or manufactured organs are historically both more complicated and more expensive. Pelling’s implants were “done without stem cells or electrical stimulation or exoskeletons, or any of the usual approaches, but rather using very low cost, accessible materials that we honestly just bought at the grocery store,” he says, “and, we achieved the same level of recovery.” (At least in animal tests.) Plus, whereas patients usually need lifelong immunosuppressants, which can have negative side effects, to prevent their body from rejecting an implant, that doesn’t seem necessary with Pelling’s plant-based implants. And, so far, the plant-based implants don’t seem to break down over time like traditional spinal-cord implants. “The inertness of plant tissue is exactly why it’s so biocompatible,” says Pelling.
In October 2020, the asparagus implant was designated as a “breakthrough device” by the FDA [US Food and Drug Administration]. The designation means human trials will be fast-tracked and likely begin in a few years. …
Shane’s August 4, 2021 article is fascinating and well illustrated with a number of embedded images. If you have the time and the inclination, do read it.
More of Pelling’s work can be found here at the Pelling Lab website. He was mentioned (by name only as a participant in the second Canadian DIY Biology Summit organized by the Public Health Agency of Canada [PHAC]) here in an April 21, 2020 posting (my 10 year review of science culture in Canada). You’ll find the Pelling mention under the DIY Biology subhead about 20% of the way down the screen.
A May 4, 2021 news item on ScienceDaily announced work that may result the restoration of nasal cartilage for skin cancer patients,
A team of University of Alberta researchers has discovered a way to use 3-D bioprinting technology to create custom-shaped cartilage for use in surgical procedures. The work aims to make it easier for surgeons to safely restore the features of skin cancer patients living with nasal cartilage defects after surgery.
The researchers used a specially designed hydrogel — a material similar to Jell-O — that could be mixed with cells harvested from a patient and then printed in a specific shape captured through 3-D imaging. Over a matter of weeks, the material is cultured in a lab to become functional cartilage.
“It takes a lifetime to make cartilage in an individual, while this method takes about four weeks. So you still expect that there will be some degree of maturity that it has to go through, especially when implanted in the body. But functionally it’s able to do the things that cartilage does,” said Adetola Adesida, a professor of surgery in the Faculty of Medicine & Dentistry.
“It has to have certain mechanical properties and it has to have strength. This meets those requirements with a material that (at the outset) is 92 per cent water,” added Yaman Boluk, a professor in the Faculty of Engineering.
Who would have thought that nose cartilage would look like a worm?
Adesida, Boluk and graduate student Xiaoyi Lan led the project to create the 3-D printed cartilage in hopes of providing a better solution for a clinical problem facing many patients with skin cancer.
Each year upwards of three million people in North America are diagnosed with non-melanoma skin cancer. Of those, 40 per cent will have lesions on their noses, with many requiring surgery to remove them. As part of the procedure, many patients may have cartilage removed, leaving facial disfiguration.
Traditionally, surgeons would take cartilage from one of the patient’s ribs and reshape it to fit the needed size and shape for reconstructive surgery. But the procedure comes with complications.
“When the surgeons restructure the nose, it is straight. But when it adapts to its new environment, it goes through a period of remodelling where it warps, almost like the curvature of the rib,” said Adesida. “Visually on the face, that’s a problem.
“The other issue is that you’re opening the rib compartment, which protects the lungs, just to restructure the nose. It’s a very vital anatomical location. The patient could have a collapsed lung and has a much higher risk of dying,” he added.
The researchers say their work is an example of both precision medicine and regenerative medicine. Lab-grown cartilage printed specifically for the patient can remove the risk of lung collapse, infection in the lungs and severe scarring at the site of a patient’s ribs.
“This is to the benefit of the patient. They can go on the operating table, have a small biopsy taken from their nose in about 30 minutes, and from there we can build different shapes of cartilage specifically for them,” said Adesida. “We can even bank the cells and use them later to build everything needed for the surgery. This is what this technology allows you to do.”
The team is continuing its research and is now testing whether the lab-grown cartilage retains its properties after transplantation in animal models. The team hopes to move the work to a clinical trial within the next two to three years.
This is a big step forward but it’s not for the faint at heart. Scientists have successfully 3D printed human skin with blood vessels and grafted them onto mice. Rensselaer Polytechnic Institute and Yale University researchers worked together on this tissue engineering project. This video features Renseellaer’s Pankaj Kraande discussing the research,
Researchers at Rensselaer Polytechnic Institute have developed a way to 3D print living skin, complete with blood vessels. The advancement, published online today [Nov. 1, 2019] in Tissue Engineering Part A, [the paper is behind a pywall] is a significant step toward creating grafts that are more like the skin our bodies produce naturally.
“Right now, whatever is available as a clinical product is more like a fancy Band-Aid,” said Pankaj Karande, an associate professor of chemical and biological engineering and member of the Center for Biotechnology and Interdisciplinary Studies (CBIS), who led this research at Rensselaer. “It provides some accelerated wound healing, but eventually it just falls off; it never really integrates with the host cells.”
A significant barrier to that integration has been the absence of a functioning vascular system in the skin grafts.
Karande has been working on this challenge for several years, previously publishing one of the first papers showing that researchers could take two types of living human cells, make them into “bio-inks,” and print them into a skin-like structure. Since then, he and his team have been working with researchers from Yale School of Medicine to incorporate vasculature.
In this paper, the researchers show that if they add key elements — including human endothelial cells, which line the inside of blood vessels, and human pericyte cells, which wrap around the endothelial cells — with animal collagen and other structural cells typically found in a skin graft, the cells start communicating and forming a biologically relevant vascular structure within the span of a few weeks. …
“As engineers working to recreate biology, we’ve always appreciated and been aware of the fact that biology is far more complex than the simple systems we make in the lab,” Karande said. “We were pleasantly surprised to find that, once we start approaching that complexity, biology takes over and starts getting closer and closer to what exists in nature.”
Once the Yale team grafted it onto a special type of mouse, the vessels from the skin printed by the Rensselaer team began to communicate and connect with the mouse’s own vessels.
“That’s extremely important, because we know there is actually a transfer of blood and nutrients to the graft which is keeping the graft alive,” Karande said.
In order to make this usable at a clinical level, researchers need to be able to edit the donor cells using something like the CRISPR technology, so that the vessels can integrate and be accepted by the patient’s body.
We are still not at that step, but we are one step closer,” Karande said.
“This significant development highlights the vast potential of 3D bioprinting in precision medicine, where solutions can be tailored to specific situations and eventually to individuals,” said Deepak Vashishth, the director CBIS. “This is a perfect example of how engineers at Rensselaer are solving challenges related to human health.”
Karande said more work will need to be done to address the challenges associated with burn patients, which include the loss of nerve and vascular endings. But the grafts his team has created bring researchers closer to helping people with more discrete issues, like diabetic or pressure ulcers.
“For those patients, these would be perfect, because ulcers usually appear at distinct locations on the body and can be addressed with smaller pieces of skin,” Karande said. “Wound healing typically takes longer in diabetic patients, and this could also help to accelerate that process.”
Very unusually, I cannot find the full title for this paper. Here’s what I found,
If successful the hope is that ‘human-on-a-chip’ will replace most, if not all, animal testing. This July 3, 2019 Hesperos news release (also on EurekAlert) suggests scientists are making serious gains in the drive to replace animal testing (Note: For anyone having difficulty with the terms, pharmacokinetics and pharmacodynamics, there are definitions towards the end of this posting, which may prove helpful),
Hesperos Inc., pioneers* of the “human-on-a-chip” in vitro system has announced the use of its innovative multi-organ model to successfully measure the concentration and metabolism of two known cardiotoxic small molecules over time, to accurately describe the drug behavior and toxic effects in vivo. The findings further support the potential of body-on-a-chip systems to transform the drug discovery process.
In a study published in Nature Scientific Reports, in collaboration with AstraZeneca, Hesperos described how they used a pumpless heart model and a heart:liver system to evaluate the temporal pharmacokinetic/pharmacodynamic (PKPD) relationship for terfenadine, an antihistamine that was banned due to toxic cardiac effects, as well as determine its mechanism of toxicity.
The study found there was a time-dependent, drug-induced response in the heart model. Further experiments were conducted, adding a metabolically competent liver module to the Hesperos Human-on-a-Chip® system to observe what happened when terfenadine was converted to fexofenadine. By doing so, the researchers were able to determine the driver of the pharmacodynamic (PD) effect and develop a mathematical model to predict the effect of terfenadine in preclinical species. This is the first time an in vitro human-on-a-chip system has been shown to predict in vivo outcomes, which could be used to predict clinical trial outcomes in the future.
“The ability to examine PKPD relationships in vitro would enable us to understand compound behavior prior to in vivo testing, offering significant cost and time savings,” said Dr. Shuler, President and CEO, Hesperos, Inc and Professor Emeritus, Cornell University. “We are excited about the potential of this technology to help us ensure that potential new drug candidates have a higher probability of success during the clinical trial process.”
Understanding the inter-relationship between pharmacokinetics (PK), the drug’s time course for absorption, distribution, metabolism and excretion, and PD, the biological effect of a drug, is crucial in drug discovery and development. Scientists have learned that the maximum drug effect is not always driven by the peak drug concentration. In some cases, time is a critical factor influencing drug effect, but often this concentration-effect-time relationship only comes to light during the advanced stages of the preclinical program. In addition, often the data cannot be reliably extrapolated to humans.
“It is costly and time consuming to discover that potential drug candidates may have poor therapeutic qualities preventing their onward progression,” said James Hickman, Chief Scientist at Hesperos and Professor at the University of Central Florida. “Being able to define this during early drug discovery will be a valuable contribution to the optimization of potential new drug candidates.”
As demonstrated with the terfenadine experiment, the PKPD modelling approach was critical for understanding both the flux of compound between compartments as well as the resulting PD response in the context of dynamic exposure profiles of both parent and metabolite, as indicated by Dr. Shuler.
In order to test the viability of their system in a real-world drug discovery setting, the Hesperos team collaborated with scientists at AstraZeneca, to test one of their failed small molecules, known to have a CV [cardiovscular?] risk.
One of the main measurements used to assess the electrical properties of the heart is the QT interval, which approximates the time taken from when the cardiac ventricles start to contract to when they finish relaxing. Prolongation of the QT interval on the electrocardiogram can lead to a fatal arrhythmia known as Torsade de Pointes. Consequently, it is a mandatory requirement prior to first-in-human administration of potential new drug candidates that their ability to inhibit the hERG channel (a biomarker for QT prolongation) is investigated.
In the case of the AstraZeneca molecule, the molecule was assessed for hERG inhibition early on, and it was concluded to have a low potential to cause in vivo QT prolongation up to 100 μM. In later pre-clinical testing, the QT interval increased by 22% at a concentration of just 3 μM. Subsequent investigations found that a major metabolite was responsible. Hesperos was able to detect a clear PD effect at concentrations above 3 μM and worked to determine the mechanism of toxicity of the molecule.
The ability of these systems to assess cardiac function non-invasively in the presence of both parent molecule and metabolite over time, using multiplexed and repeat drug dosing regimes, provides an opportunity to run long-term studies for chronic administration of drugs to study their potential toxic effects.
Hesperos, Inc. is the first company spun out from the Tissue Chip Program at NCATS (National Center for Advancing Translational Sciences), which was established in 2011 to address the long timelines, steep costs and high failure rates associated with the drug development process. Hesperos currently is funded through NCATS’ Small Business Innovation Research program to undertake these studies and make tissue chips technology available as a service based company.
“The application of tissue chip technology in drug testing can lead to advances in predicting the potential effects of candidate medicines in people,” said Danilo Tagle, Ph.D., associate director for special initiatives at NCATS.
About Hesperos Hesperos, Inc. is a leader in efforts to characterize an individual’s biology with human-on-a-chip microfluidic systems. Founders Michael L. Shuler and James J. Hickman have been at the forefront of every major scientific discovery in this realm, from individual organ-on-a-chip constructs to fully functional, interconnected multi-organ systems. With a mission to revolutionize toxicology testing as well as efficacy evaluation for drug discovery, the company has created pumpless platforms with serum-free cellular mediums that allow multi-organ system communication and integrated computational PKPD modeling of live physiological responses utilizing functional readouts from neurons, cardiac, muscle, barrier tissues and neuromuscular junctions as well as responses from liver, pancreas and barrier tissues. Created from human stem cells, the fully human systems are the first in vitro solutions that accurately utilize in vitro systems to predict in vivo functions without the use of animal models, as featured in Science. More information is available at http://www. hesperosinc.com
Years ago I went to a congress focused on alternatives to animal testing (August 22, 2014 posting) and saw a video of heart cells in a petri dish (in vitro) beating in a heartlike rhythm. It was something like this,
ipscira Published on Oct 17, 2010 https://www.youtube.com/watch?v=BqzW9Jq-OVA
I found it amazing as did the scientist who drew my attention to it. After, it’s just a collection of heart cells. How do they start beating and keep time with each other?
Getting back to the latest research, here’s a link and a citation for the paper,
On the potential of in vitro organ-chip models to define temporal pharmacokinetic-pharmacodynamic relationships by Christopher W. McAleer, Amy Pointon, Christopher J. Long, Rocky L. Brighton, Benjamin D. Wilkin, L. Richard Bridges, Narasimham Narasimhan Sriram, Kristin Fabre, Robin McDougall, Victorine P. Muse, Jerome T. Mettetal, Abhishek Srivastava, Dominic Williams, Mark T. Schnepper, Jeff L. Roles, Michael L. Shuler, James J. Hickman & Lorna Ewart. Scientific Reports volume 9, Article number: 9619 (2019) DOI: https://doi.org/10.1038/s41598-019-45656-4 Published: 03 July 2019
Integrative pharmacology is a discipline that builds an understanding of the inter-relationship between pharmacokinetics (PK), the drug’s time course for absorption, distribution, metabolism and excretion and pharmacodynamics (PD), the biological effect of a drug. In drug discovery, this multi-variate approach guides medicinal chemists to modify structural properties of a drug molecule to improve its chance of becoming a medicine in a process known as “lead optimization”.
*More than one person and more than one company and more than one country claims pioneer status where ‘human-on-a-chip’ is concerned.
In a major medical breakthrough, Tel Aviv University researchers have “printed” the world’s first 3D vascularised engineered heart using a patient’s own cells and biological materials. Their findings were published on April 15  in a study in Advanced Science.
Until now, scientists in regenerative medicine — a field positioned at the crossroads of biology and technology — have been successful in printing only simple tissues without blood vessels.
“This is the first time anyone anywhere has successfully engineered and printed an entire heart replete with cells, blood vessels, ventricles and chambers,” says Prof. Tal Dvir of TAU’s School of Molecular Cell Biology and Biotechnology, Department of Materials Science and Engineering, Center for Nanoscience and Nanotechnology and Sagol Center for Regenerative Biotechnology, who led the research for the study.
Heart disease is the leading cause of death among both men and women in the United States. Heart transplantation is currently the only treatment available to patients with end-stage heart failure. Given the dire shortage of heart donors, the need to develop new approaches to regenerate the diseased heart is urgent.
“This heart is made from human cells and patient-specific biological materials. In our process these materials serve as the bioinks, substances made of sugars and proteins that can be used for 3D printing of complex tissue models,” Prof. Dvir says. “People have managed to 3D-print the structure of a heart in the past, but not with cells or with blood vessels. Our results demonstrate the potential of our approach for engineering personalized tissue and organ replacement in the future.
Research for the study was conducted jointly by Prof. Dvir, Dr. Assaf Shapira of TAU’s Faculty of Life Sciences and Nadav Moor, a doctoral student in Prof. Dvir’s lab.
“At this stage, our 3D heart is small, the size of a rabbit’s heart, [emphasis mine] ” explains Prof. Dvir. “But larger human hearts require the same technology.”
For the research, a biopsy of fatty tissue was taken from patients. The cellular and a-cellular materials of the tissue were then separated. While the cells were reprogrammed to become pluripotent stem cells, the extracellular matrix (ECM), a three-dimensional network of extracellular macromolecules such as collagen and glycoproteins, were processed into a personalized hydrogel that served as the printing “ink.”
After being mixed with the hydrogel, the cells were efficiently differentiated to cardiac or endothelial cells to create patient-specific, immune-compatible cardiac patches with blood vessels and, subsequently, an entire heart.
According to Prof. Dvir, the use of “native” patient-specific materials is crucial to successfully engineering tissues and organs.
“The biocompatibility of engineered materials is crucial to eliminating the risk of implant rejection, which jeopardizes the success of such treatments,” Prof. Dvir says. “Ideally, the biomaterial should possess the same biochemical, mechanical and topographical properties of the patient’s own tissues. Here, we can report a simple approach to 3D-printed thick, vascularized and perfusable cardiac tissues that completely match the immunological, cellular, biochemical and anatomical properties of the patient.”
The researchers are now planning on culturing the printed hearts in the lab and “teaching them to behave” like hearts, Prof. Dvir says. They then plan to transplant the 3D-printed heart in animal models.
“We need to develop the printed heart further,” he concludes. “The cells need to form a pumping ability; they can currently contract, but we need them to work together. Our hope is that we will succeed and prove our method’s efficacy and usefulness.
“Maybe, in ten years, there will be organ printers in the finest hospitals around the world, and these procedures will be conducted routinely.”
Growing the heart to human size and getting the cells to work together so the heart will pump makes it seem like the 10 years Dvir imagines as the future date when there will be organ printers in hospitals routinely printing up hearts seems a bit optimistic. Regardless, I hope he’s right. Bravo to these Israeli researchers!
Two research groups are working to the same end where bone marrow is concerned, encourage bone cell growth, but they are using different strategies.
University of British Columbia and McMaster University (Canada)
The samples look a little like teeth, don’t they?
Before diving into the research news, there’s a terminology issue that should be noted as you’ll see when you read the news/press releases. Nanocrystal cellulose/nanocrystalline cellulose (NCC) is a term coined by Canadian researchers. Since those early day, most researchers, internationally, have adopted the term cellulose nanocrystals (CNC) as the standard term. It fits better with the naming conventions for other nnanocellulose materials such as cellulose nanofibrils, etc. By the way, a Canadian company (CelluForce) that produces CNC retained the term nanocrystalline cellulose (NCC) as a trademark for the product, CelluForce NCC®.
For anyone not familiar with aerogels, what the University of British Columbia (UBC) and McMaster University researchers are developing, are also popularly known known as ‘frozen smoke’ (see the Aerogel Wikipedia entry for more).
Researchers from the University of British Columbia and McMaster University have developed what could be the bone implant material of the future: an airy, foamlike substance that can be injected into the body and provide scaffolding for the growth of new bone.
It’s made by treating nanocrystals derived from plant cellulose so that they link up and form a strong but lightweight sponge — technically speaking, an aerogel — that can compress or expand as needed to completely fill out a bone cavity.
“Most bone graft or implants are made of hard, brittle ceramic that doesn’t always conform to the shape of the hole, and those gaps can lead to poor growth of the bone and implant failure,” said study author Daniel Osorio, a PhD student in chemical engineering at McMaster. “We created this cellulose nanocrystal aerogel as a more effective alternative to these synthetic materials.”
For their research, the team worked with two groups of rats, with the first group receiving the aerogel implants and the second group receiving none. Results showed that the group with implants saw 33 per cent more bone growth at the three-week mark and 50 per cent more bone growth at the 12-week mark, compared to the controls.
“These findings show, for the first time in a lab setting, that a cellulose nanocrystal aerogel can support new bone growth,” said study co-author Emily Cranston, a professor of wood science and chemical and biological engineering who holds the President’s Excellence Chair in Forest Bio-products at UBC. She added that the implant should break down into non-toxic components in the body as the bone starts to heal.
The innovation can potentially fill a niche in the $2-billion bone graft market in North America, said study co-author Kathryn Grandfield, a professor of materials science and engineering, and biomedical engineering at McMaster who supervised the work.
“We can see this aerogel being used for a number of applications including dental implants and spinal and joint replacement surgeries,” said Grandfield. “And it will be economical because the raw material, the nanocellulose, is already being produced in commercial quantities.”
The researchers say it will be some time before the aerogel makes it out of the lab and into the operating room.
“This summer, we will study the mechanisms between the bone and implant that lead to bone growth,” said Grandfield. “We’ll also look at how the implant degrades using advanced microscopes. After that, more biological testing will be required before it is ready for clinical trials.”
National University of Science and Technology “MISIS” (formerly part of the Moscow Mining Academy)
These scientists have adopted a different strategy as you’ll see in the March 19, 2019 news item on Nanwerk, which, coincidentally, was published on the same day as the Canadian research,
Scientists from the National University of Science and Technology “MISIS” developed a nanomaterial, which will be able to rstore the internal structure of bones damaged due to osteoporosis and osteomyelitis. A special bioactive coating of the material helped to increase the rate of division of bone cells by 3 times. In the future, it can allow to abandon bone marrow transplantation and patients will no longer need to wait for suitable donor material.
Such diseases as osteoporosis and osteomyelitis cause irreversible degenerative changes in the bone structure. Such diseases require serious complex treatment and surgery and transplantation of the destroyed bone marrow in severe stages. Donor material should have a number of compatibility indicators and even close relationship with the donor cannot guarantee full compatibility.
Research group from the National University of Science and Technology “MISIS” (NUST MISIS), led by Anton Manakhov (Laboratory for Inorganic Nanomaterials) developed material that will allow to restore damaged internal bone structure without bone marrow transplantation. It is based on nanofibers of polycaprolactone, which is biocompatible self-dissolvable material. Earlier, the same research group has already worked with this material: by adding antibiotics to the nanofibers, scientists have managed to create non-changeable healing bandages.
“If we want the implant to take, not only biocompatibility is needed, but also activation of the natural cell growth on the surface of the material. Polycaprolactone as such is a hydrophobic material, meaning, and cells feel uncomfortable on its surface. They gather on the smooth surface and divide extremely slow”, Elizaveta Permyakova, one of the co-authors and researcher at NUST MISIS Laboratory for Inorganic Nanomaterials, explains.
To increase the hydrophilicity of the material, a thin layer of bioactive film consisting of titanium, calcium, phosphorus, carbon, oxygen and nitrogen (TiCaPCON) was deposited on it. The structure of nanofibers identical to the cell surface was preserved. These films, when immersed in a special salt medium, which chemical composition is identical to human blood plasma, are able to form on its surface a special layer of calcium and phosphorus, which in natural conditions forms the main part of the bone. Due to the chemical similarity and the structure of nanofibers, new bone tissue begins to grow rapidly on this layer. Most importantly, polycaprolactone nanofibers dissolve, having fulfilled their functions. Only new “native” tissue remains in the bone.
In the experimental part of the study, the researchers compared the rate of division of osteoblastic bone cells on the surface of the modified and unmodified material. It was found that the modified material TiCaPCON has a high hydrophilicity. In contrast to the unmodified material, the cells on its surface felt clearly more comfortable, and divided three times faster.
According to scientists, such results open up great prospects for further work with modified polycaprolactone nanofibers as an alternative to bone marrow transplantation.
I have two stories about lungs and they are entirely different with the older one being a bioengineering story from the US and the more recent one being an artificial tissue story from the University of Toronto and the University of Ottawa (both in Canada).
Lab grown lungs
The Canadian Broadcasting Corporation’s Quirks and Quarks radio programme posted a December 29, 2018 news item (with embedded radio files) about bioengineered lunjgs,
There are two major components to building an organ: the structure and the right cells on that structure. A team led by Dr. Joan Nichols, a Professor of Internal Medicine, Microbiology and Immunology at the University of Texas Medical Branch in Galveston, were able to tackle both parts of the problem
In their experiment they used a donor organ for the structure. They took a lung from an unrelated pig, and stripped it of its cells, leaving a scaffold of collagen, a tough, flexible protein. This provided a pre-made appropriate structure, though in future they think it may be possible to use 3-D printing technology to get the same result.
They then added cultured cells from the animal who would be receiving the transplant – so the lung was made of the animal’s own cells. Cultured lung and blood vessel cells were placed on the scaffold and it was placed in a tank for 30 days with a cocktail of nutrients to help the cells stick to the scaffold and proliferate. The result was a kind of baby lung.
They then transplanted the bio-engineered, though immature, lung into the recipient animal where they hoped it would continue to develop and mature – growing to become a healthy, functioning organ.
The recipients of the bio-engineered lungs were four pigs adult pigs, which appeared to tolerate the transplants well. In order to study the development of the bio-engineered lungs, they euthanized the animals at different times: 10 hours, two weeks, one month and two months after transplantation.
They found that as early as two weeks, the bio-engineered lung had integrated into the recipient animals’ body, building a strong network of blood vessels essential for the lung to survive. There was no evidence of pulmonary edema, the build of fluid in the lungs, which is usually a sign of the blood vessels not working efficiently. There was no sign of rejection of the transplanted organs, and the pigs were healthy up to the point where they were euthanized.
One lingering concern is how well the bio-engineered lungs delivered oxygen. The four pigs who received the trasplant [sic] had one original functioning lung, so they didn’t depend on their new bio-engineered lung for breathing. The scientists were not sure that the bio-engineered lung was mature enough to handle the full load of oxygen on its own.
You can hear Bob McDonald’s (host of Quirks & Quarks, a Canadian Broadcasting Corporation science radio programme) interview lead scientist, Dr. Joan Nichols if you go to here. (Note: I find he overmodulates his voice but some may find he has a ‘friendly’ voice.)
This is an image of the lung scaffold produced by the team,
In 2014, Joan Nichols and Joaquin Cortiella from The University of Texas Medical Branch at Galveston were the first research team to successfully bioengineer human lungs in a lab. In a paper now available in Science Translational Medicine, they provide details of how their work has progressed from 2014 to the point no complications have occurred in the pigs as part of standard preclinical testing.
“The number of people who have developed severe lung injuries has increased worldwide, while the number of available transplantable organs have decreased,” said Cortiella, professor of pediatric anesthesia. “Our ultimate goal is to eventually provide new options for the many people awaiting a transplant,” said Nichols, professor of internal medicine and associate director of the Galveston National Laboratory at UTMB.
To produce a bioengineered lung, a support scaffold is needed that meets the structural needs of a lung. A support scaffold was created using a lung from an unrelated animal that was treated using a special mixture of sugar and detergent to eliminate all cells and blood in the lung, leaving only the scaffolding proteins or skeleton of the lung behind. This is a lung-shaped scaffold made totally from lung proteins.
The cells used to produce each bioengineered lung came from a single lung removed from each of the study animals. This was the source of the cells used to produce a tissue-matched bioengineered lung for each animal in the study. The lung scaffold was placed into a tank filled with a carefully blended cocktail of nutrients and the animals’ own cells were added to the scaffold following a carefully designed protocol or recipe. The bioengineered lungs were grown in a bioreactor for 30 days prior to transplantation. Animal recipients were survived for 10 hours, two weeks, one month and two months after transplantation, allowing the research team to examine development of the lung tissue following transplantation and how the bioengineered lung would integrate with the body.
All of the pigs that received a bioengineered lung stayed healthy. As early as two weeks post-transplant, the bioengineered lung had established the strong network of blood vessels needed for the lung to survive.
“We saw no signs of pulmonary edema, which is usually a sign of the vasculature not being mature enough,” said Nichols and Cortiella. “The bioengineered lungs continued to develop post-transplant without any infusions of growth factors, the body provided all of the building blocks that the new lungs needed.”
Nichols said that the focus of the study was to learn how well the bioengineered lung adapted and continued to mature within a large, living body. They didn’t evaluate how much the bioengineered lung provided oxygenation to the animal.
“We do know that the animals had 100 percent oxygen saturation, as they had one normal functioning lung,” said Cortiella. “Even after two months, the bioengineered lung was not yet mature enough for us to stop the animal from breathing on the normal lung and switch to just the bioengineered lung.”
For this reason, future studies will look at long-term survival and maturation of the tissues as well as gas exchange capability.
The researchers said that with enough funding, they could grow lungs to transplant into people in compassionate use circumstances within five to 10 years.
“It has taken a lot of heart and 15 years of research to get us this far, our team has done something incredible with a ridiculously small budget and an amazingly dedicated group of people,” Nichols and Cortiella said.
Here’s a citation and another link for the paper,
Production and transplantation of bioengineered lung into a large-animal model by Joan E. Nichols, Saverio La Francesca, Jean A. Niles, Stephanie P. Vega, Lissenya B. Argueta, Luba Frank, David C. Christiani, Richard B. Pyles, Blanca E. Himes, Ruyang Zhang, Su Li, Jason Sakamoto, Jessica Rhudy, Greg Hendricks, Filippo Begarani, Xuewu Liu, Igor Patrikeev, Rahul Pal, Emiliya Usheva, Grace Vargas, Aaron Miller, Lee Woodson, Adam Wacher, Maria Grimaldo, Daniil Weaver, Ron Mlcak, and Joaquin Cortiella. Science Translational Medicine 01 Aug 2018: Vol. 10, Issue 452, eaao3926 DOI: 10.1126/scitranslmed.aao3926
This paper is behind a paywall.
Artificial lung cancer tissue
The research teams at the University of Toronto and the University of Ottawa worked on creating artificial lung tissue but other applications are possible too. First, there’s the announcement in a February 25, 2019 news item on phys.org,
A 3-D hydrogel created by researchers in U of T Engineering Professor Molly Shoichet’s lab is helping University of Ottawa researchers to quickly screen hundreds of potential drugs for their ability to fight highly invasive cancers.
Cell invasion is a critical hallmark of metastatic cancers, such as certain types of lung and brain cancer. Fighting these cancers requires therapies that can both kill cancer cells as well as prevent cell invasion of healthy tissue. Today, most cancer drugs are only screened for their ability to kill cancer cells.
“In highly invasive diseases, there is a crucial need to screen for both of these functions,” says Shoichet. “We now have a way to do this.”
In their latest research, the team used hydrogels to mimic the environment of lung cancer, selectively allowing cancer cells, and not healthy cells, to invade. In their latest research, the team used hydrogels to mimic the environment of lung cancer, selectively allowing cancer cells, and not healthy cells, to invade. This emulated environment enabled their collaborators in Professor Bill Stanford’s lab at University of Ottawa to screen for both cancer-cell growth and invasion. The study, led by Roger Y. Tam, a research associate in Shochet’s lab, was recently published in Advanced Materials.
“We can conduct this in a 384-well plate, which is no bigger than your hand. And with image-analysis software, we can automate this method to enable quick, targeted screenings for hundreds of potential cancer treatments,” says Shoichet.
One example is the researchers’ drug screening for lymphangioleiomyomatosis (LAM), a rare lung disease affecting women. Shoichet and her team were inspired by the work of Green Eggs and LAM, a Toronto-based organization raising awareness of the disease.
Using their hydrogels, they were able to automate and screen more than 800 drugs, thereby uncovering treatments that could target disease growth and invasion.
In the ongoing collaboration, the researchers plan to next screen multiple drugs at different doses to gain greater insight into new treatment methods for LAM. The strategies and insights they gain could also help identify new drugs for other invasive cancers.
Shoichet, who was recently named a Distinguished Woman in Chemistry or Chemical Engineering, also plans to patent the hydrogel technology.
“This has, and continues to be, a great collaboration that is advancing knowledge at the intersection of engineering and biology,” says Shoichet.
I note that Shoichet (pronounced ShoyKet) is getting ready to patent this work. I do have a question about this and it’s not up to Shoichet to answer as she didn’t create the system. Will the taxpayers who funded her work receive any financial benefits should the hydrogel prove to be successful or will we be paying double, both supporting her research and paying for the hydrogel through our healthcare costs?
Getting back to the research, here’s a link to and a citation for the paper,
It’s been a while since I’ve had a story abut cellulose nanocrystals (CNC) and this one comes from Switzerland’s Empa (Swiss Federal Laboratories for Materials Science and Technology) in a January 15, 2019 news item on Nanowerk (Note: A link has been removed),
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing (ACS Nano, “Dynamics of Cellulose Nanocrystal Alignment during 3D Printing”).
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains: “In viscous state cellulose nanocrystals can easily be shaped together with nother biopolymers into complex 3-dimensional structures using a 3D printer, such as the Bioplotter.”
Once cross-linked, the structures remain stable despite their soft mechanical properties. Hausmann is currently investigating the characteristics of the nanocellulose composite hydrogels in order to further optimize their stability as well as the printing process. The researcher already used X-ray analysis to determine how cellulose is distributed and organized within the printed structures.
At this point in time the printed ear is entirely and solely made of cellulose nanocrystals and a biopolymer. However, the objective is to incorporate both human cells and therapeutics into the base structure in order to produce biomedical implants.
Here’s one of the researchers (Michael Hausmann) showing off their ‘ear’,
Doesn’t look like much does, eh? It’s scaffolding or, you could say, a kind of skeleton and a January 15, 2019 Empa press release, which originated the news item, describes it and explains how it will house new cells,
A new project is currently underway, looking into how chondrocytes (cartilage cells) can be integrated into the scaffold to yield artificial cartilage tissue. As soon as the colonization of the hydrogel with cells is established, nanocellulose based composites in the shape of an ear could serve as an implant for children with an inherited auricular malformation as for instance, in microtia, where the external ears are only incompletely developed. A reconstruction of the auricle can esthetically and medically correct the malformation; otherwise the hearing ability can be severely impaired. In the further course of the project, cellulose nanocrystals containing hydrogels will also be used for the replacement of articular cartilage (e.g. knee) in cases of joint wear due to, for example, chronic arthritis.
Once the artificial tissue has been implanted in the body, the biodegradable polymer material is expected to degrade over time. The cellulose itself is not degradable in the body, but biocompatible. However, it is not only its biocompatibility that makes nanocellulose the perfect material for implant scaffolds. “It is also the mechanical performance of cellulose nanocrystals that make them such promising candidates because the tiny but highly stable fibers can extremely well reinforce the produced implant,” said Hausmann.
Moreover, nanocellulose allows the incorporation of various functions by chemical modifications into the viscous hydrogel. Thus, the structure, the mechanical properties and the interactions of the nanocellulose with its environment can be specifically tailored to the desired end product. “For instance, we can incorporate active substances that promote the growth of chondrocytes or that sooth joint inflammation into the hydrogel,” says the Empa researcher.
And last but not least, as raw material cellulose is the most abundant natural polymer on earth. Therefore, the use of cellulose nanocrystals not only benefits from the mere elegance of the novel process but also from the availability of the raw material.
The white nanocellulose ear lies glossy on the glass carrier. Just out of the Bioplotter, it is already robust and dimensionally stable. Hausmann can give the go-ahead for the next steps.
I.M. Sechenov First Moscow State Medical University teamed up together with Irish colleagues to develop a new imaging approach for tissue engineering. The team produced so-called ‘hybrid biosensor’ scaffold materials, which are based on cellulose matrices labeled with pH- and calcium-sensitive fluorescent proteins. These materials enable visualization of the metabolism and other important biomarkers in the engineered artificial tissues by microscopy. The results of the work were published in the Acta Biomaterialia journal. The success of tissue engineering is based on the use of scaffold matrices – materials that support the viability and direct the growth of cells, tissues, and organoids. Scaffolds are important for basic and applied biomedical research, tissue engineering and regenerative medicine, and are promising for development of new therapeutics. However, the ability ‘to see’ what happens within the scaffolds during the tissue growth poses a significant research challenge
“We developed a new approach allowing visualization of scaffold-grown tissue and cells by using labeling with biosensor fluorescent proteins. Due to the high specificity of labeling and the use of fluorescence microscopy FLIM, we can quantify changes in pH and calcium in the vicinity of cells,” says Dr. Ruslan Dmitriev, Group Leader at the University College Cork and the Institute for Regenerative Medicine (I.M. Sechenov First Moscow State Medical University). To achieve the specific labeling of cellulose matrices, researchers used well-known cellulose-binding proteins. The use of extracellular pH- and calcium-sensitive biosensors allow for analysis of cell metabolism: indeed, the extracellular acidification is directly associated with the balance of cell energy production pathways and the glycolytic flux (release of lactate). It is also a frequent hallmark of cancer and transformed cell types. On the other hand, calcium plays a key role in the extra- and intracellular signaling affecting cell growth and differentiation.
The approach was tested on different types of cellulose matrices (bacterial and produced from decellularised plant tissues) using 3D culture of human colon cancer cells and stem-cell derived mouse small intestinal organoids. The scaffolds informed on changes in the extracellular acidification and were used together with the analysis of real-time oxygenation of intestinal organoids. The resulting data can be presented in the form of colour maps, corresponding to the areas of cell growth within different microenvironments.
“Our results open new prospects in the imaging of tissue-engineered constructs for regenerative medicine. They enable deeper understanding of tissue metabolism in 3D and are also highly promising for commercialisation,” concludes Dr. Dmitriev.
The researchers have provided an image to illustrate their work,
This charming illustration is the only pictorial representation i’ve seen for Kyoto University’s (Japan) proposed periodic table of nanomaterials, (By the way, 2019 is UNESCO’s [United Nations Educational, Scientific and Cultural Organization] International Year of the Periodic Table of Elements, an event recognizing the table’s 150th anniversary. See my January 8, 2019 posting for information about more events.)
Caption: Molecules interact and align with each other as they self-assemble. This new simulation enables to find what molecules best interact with each other to build nanomaterials, such as materials that work as a nano electrical wire. Credit Illustration by Izumi Mindy Takamiya
The approach was developed by Daniel Packwood of Kyoto University’s Institute for Integrated Cell-Material Sciences (iCeMS) and Taro Hitosugi of the Tokyo Institute of Technology (Nature Communications, “Materials informatics for self-assembly of functionalized organic precursors on metal surfaces”). It involves connecting the chemical properties of molecules with the nanostructures that form as a result of their interaction. A machine learning technique generates data that is then used to develop a diagram that categorizes different molecules according to the nano-sized shapes they form.
This approach could help materials scientists identify the appropriate molecules to use in order to synthesize target nanomaterials.
Fabricating nanomaterials using a bottom-up approach requires finding ‘precursor molecules’ that interact and align correctly with each other as they self-assemble. But it’s been a major challenge knowing how precursor molecules will interact and what shapes they will form.
Bottom-up fabrication of graphene nanoribbons is receiving much attention due to their potential use in electronics, tissue engineering, construction, and bio-imaging. One way to synthesise them is by using bianthracene precursor molecules that have bromine ‘functional’ groups attached to them. The bromine groups interact with a copper substrate to form nano-sized chains. When these chains are heated, they turn into graphene nanoribbons.
Packwood and Hitosugi tested their simulator using this method for building graphene nanoribbons.
Data was input into the model about the chemical properties of a variety of molecules that can be attached to bianthracene to ‘functionalize’ it and facilitate its interaction with copper. The data went through a series of processes that ultimately led to the formation of a ‘dendrogram’.
This showed that attaching hydrogen molecules to bianthracene led to the development of strong one-dimensional nano-chains. Fluorine, bromine, chlorine, amidogen, and vinyl functional groups led to the formation of moderately strong nano-chains. Trifluoromethyl and methyl functional groups led to the formation of weak one-dimensional islands of molecules, and hydroxide and aldehyde groups led to the formation of strong two-dimensional tile-shaped islands.
The information produced in the dendogram changed based on the temperature data provided. The above categories apply when the interactions are conducted at -73°C. The results changed with warmer temperatures. The researchers recommend applying the data at low temperatures where the effect of the functional groups’ chemical properties on nano-shapes are most clear.
The technique can be applied to other substrates and precursor molecules. The researchers describe their method as analogous to the periodic table of chemical elements, which groups atoms based on how they bond to each other. “However, in order to truly prove that the dendrograms or other informatics-based approaches can be as valuable to materials science as the periodic table, we must incorporate them in a real bottom-up nanomaterial fabrication experiment,” the researchers conclude in their study published in the journal xxx. “We are currently pursuing this direction in our laboratories.”