bioengineering

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Living Tissue Emerges From 3-D Printer

Harvard bioengineers say they have taken a big step toward using 3-D printers to make living tissue. They’ve made a machine with multiple printer heads that each extrudes a different biological building block to make complex tissue and blood vessels.

Their work represents a significant advance toward producing living medical models upon which drugs could be tested for safety and effectiveness.

It also advances the ball in the direction of an even bigger goal. Such a machine and the techniques being refined by researchers offer a glimpse of the early steps in a sci-fi healthcare scenario: One day surgeons might feed detailed CT scans of human body parts into a 3-D printer, manipulate them with design software, and produce healthy replacements for diseased or injured tissues or organs.

Read more below and click the gifs for explanations. 

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A new gel helps wounds heal

Researchers from UCLA have developed an injectable hydrogel that helps skin wounds heal faster. 

The new synthetic polymer material creates an instant scaffold, sort of like stacked gumballs, that allows new tissue to latch on and grow within the cavities formed between linked spheres of gel.

Conventionally, ointments and other hydrogel dressings have been used to fill in wounds to keep the areas moist and accelerate healing. But none of the materials used now provide a scaffold to allow new tissue to grow while the dressing itself degrades. As a result, the new tissue growth is relatively slow and fragile.

So bringing about an injectable biomaterial that promotes rapid regeneration of tissue has been a “holy grail” in the field of tissue engineering, said co-principal investigator Dino Di Carlo.

They envision the material being useful for a wide variety of wound application, including lacerations to large-area burns.

UC Berkeley researchers have also been developing new approaches to tissue engineering. Last March, their advancement in “herding cells” marked a new direction for smart bandages.

Learn more about how this new gel works

5 Body Parts Scientists Can 3-D Print

Ears

Team: Cornell University

How it’s made: Bioengineers take a 3-D scan of a child’s ear, design a seven-part mold in the SolidWorks CAD program, and print the pieces. The mold is injected with a high-density gel made from 250 million bovine cartilage cells and collagen from rat tails (the latter serves as a scaffold). After 15 minutes, the ear is removed and incubated in cell culture for several days. In three months, the cartilage will have propagated enough to replace the collagen.

Benefit: At least one child in 12,500 is born with microtia, a condition characterized by hearing loss due to an underdeveloped or malformed outer ear. Unlike synthetic implants, ears grown from human cells are more likely to be successfully incorporated into the body.

See Slideshow

This Week in Science - April 29 - May 5, 2013:

  • Smallest movie ever made here.
  • Sea horse armor inspires engineers here.
  • New insect-eye-like-camera here.
  • Bioengineered windpipe here.
  • Bionic ear here.
  • Anti-matter falling up here.
  • Harvard robotocists fly RoboBee here.
  • Saturn’s seasonal magnetosphere here.
  • Vega launches here.
  • Climate change causing painted turtles extinction here.
  • Black hole birth observed for first time here.
  • New species of mole rat here.

Bioengineered forelimb is fully transplantable with functioning muscle and vascular tissue

A team of Massachusetts General Hospital (MGH) investigators has made the first steps towards development of bioartificial replacement limbs suitable for transplantation. In their report, which has been published online in the journal Biomaterials, the researchers describe using an experimental approach previously used to build bioartificial organs to engineer rat forelimbs with functioning vascular and muscle tissue. They also provided evidence that the same approach could be applied to the limbs of primates

“The composite nature of our limbs makes building a functional biological replacement particularly challenging,” explains Harald Ott, MD, of the MGH Department of Surgery and the Center for Regenerative Medicine, senior author of the paper. “Limbs contain muscles, bone, cartilage, blood vessels, tendons, ligaments and nerves - each of which has to be rebuilt and requires a specific supporting structure called the matrix. We have shown that we can maintain the matrix of all of these tissues in their natural relationships to each other, that we can culture the entire construct over prolonged periods of time, and that we can repopulate the vascular system and musculature.”

READ MORE ON MEDICAL XPRESS

Ref:  Engineered composite tissue as a bioartificial limb graft. Biomaterials (2015) |DOI:10.1016/j.biomaterials.2015.04.051

Abstract
The loss of an extremity is a disastrous injury with tremendous impact on a patient’s life. Current mechanical prostheses are technically highly sophisticated, but only partially replace physiologic function and aesthetic appearance. As a biologic alternative, approximately 70 patients have undergone allogeneic hand transplantation to date worldwide. While outcomes are favorable, risks and side effects of transplantation and long-term immunosuppression pose a significant ethical dilemma. An autologous, bio-artificial graft based on native extracellular matrix and patient derived cells could be produced on demand and would not require immunosuppression after transplantation. To create such a graft, we decellularized rat and primate forearms by detergent perfusion and yielded acellular scaffolds with preserved composite architecture. We then repopulated muscle and vasculature with cells of appropriate phenotypes, and matured the composite tissue in a perfusion bioreactor under electrical stimulation in vitro. After confirmation of composite tissue formation, we transplanted the resulting bio-composite grafts to confirm perfusion in vivo.

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Fashion 2050: Biolace

Carole Collet is a professor in Design for Sustainable Futures and Director of Design & Living Systems Lab, focusing her research on biodesign, biofacturing, high-tech sustainability. Collet is also a pioneer of the Textile Futures discipline at Central Saint Martins.

What is unique about Collet’s work is that most of her projects are fictional, in the sense that they represent possible products or situations in the year 2050 and beyond.

One such fictional project, is “Biolace” (2010-2012), a series of four plants, Strawberry Noir, Basil n 5, Tomato Factor 60, and GoldNano Spinach, which are presented in a hyper-engineered state. The works are provocative, in the sense that they bring up discussions of the pros and cons of living technologies and genetic engineering. How far is ‘too far’ when it comes to controlling living organisms to our benefit? What happens when these plants become a reality? The main goal is to eliminate chemical-based textile manufacturing while also harvesting food to eat. 

But would you, as the artist states, “eat a vitamin-rich black strawberry from a plant that has also produced your little black dress?”

In the future, plants may become multi-purpose factories, producing both food and fabric. Instead of polluting the air with gas or the water with runoff like in a traditional factory, water and sunlight are the only fuels these ‘factories’ would need. Sustainability has never looked (and tasted!) so good.

- Anna Paluch

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The Magic of Carefully Crafting Liquids

Droplets containing two liquids with different properties can be made into fluid machines. Engineers in the lab of Stanford University’s Manu Prakash (creator of the 50-cent paper microscope) found that mixtures of simple ingredients like water and propylene glycol-based food coloring could propel themselves in intricate patterns and move other droplets around a standard glass slide.

“We demonstrate experimentally and analytically that these droplets are stabilized by evaporation-induced surface tension gradients and that they move in response to the vapour emitted by neighbouring droplets,” the authors write in a paper published yesterday in the journal Nature. “Our fundamental understanding of this robust system enabled us to construct a wide variety of autonomous fluidic machines out of everyday materials.”

The work trying to understand the dynamics of these different fluids began with an unexpected observation by coauthor and bioengineering graduate student Nate Cira in 2009. While completing an unrelated experiment as an undergraduate, Cira noticed that drops of food coloring began to move of their own accord on a glass slide. See video below.

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3-D Printed Windpipe Gives Infant Breath of Life

A flexible, absorbable tube helps a baby boy breathe, and heralds a future of body parts printed on command.

Kaiba Gionfriddo was six weeks old when he suddenly stopped breathing and turned blue at a restaurant. Kaiba’s parents quickly rushed him to the hospital where they learned that his left bronchial tube had collapsed because of a previously undetected birth defect. During the next few weeks the life-threatening attacks recurred, increasing in number until they became everyday events. Physicians and researchers, however, used some of the most sophisticated bioengineering techniques available to 3-D print a synthetic tube to hold the baby’s airway open. Kaiba had the surgery in January 2012 and hasn’t suffered an airway collapse since.

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Cultured meat

The left column shows the stepwise increase in cell-culture volume, starting with a vial from the working cell bank (note that a new working cell bank is made from a vial from the master cell bank). Exponentially growing cells from each step serve, after growing to a certain cell density, as the inoculum of the next culture vessel, which is an order of magnitude larger. The final bioreactor starts only partially filled and is fed with sterile medium at such a rate that the cells grow further under optimal conditions.

When the bioreactor is full and the desired cell density is reached, the protein-crosslinking enzyme transglutaminase and binding protein are added to induce the formation of easily settling aggregates of cells, which quickly settle when stirring is stopped (bottom right). The harvested cells are pressed and the cake is extruded into retailer- and/or consumer-size portions of minced meat (right column).

Source: cell.com

So, would you eat meat made from stem cells?

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Bioengineers put human hearts on a chip

UC Berkeley bioengineers have built a heart-on-a-chip. The inch-long silicone device effectively models human heart tissue — a major step in the development of a fast, accurate method for testing for drug toxicity.

“Ultimately, these chips could replace the use of animals to screen drugs for safety and efficacy,” said Healy.

The study authors noted a high failure rate associated with the use of nonhuman animal models to predict human reactions to new drugs. Much of this is due to fundamental differences in biology between species, the researchers explained. For instance, the ion channels through which heart cells conduct electrical currents can vary in both number and type between humans and other animals.

“Many cardiovascular drugs target those channels, so these differences often result in inefficient and costly experiments that do not provide accurate answers about the toxicity of a drug in humans,” said Healy. “It takes about $5 billion on average to develop a drug, and 60 percent of that figure comes from upfront costs in the research and development phase. Using a well-designed model of a human organ could significantly cut the cost and time of bringing a new drug to market.”

Say good-bye to root canals and fillings! The Gizmodo article (excerpt below) has the story….

The current study builds on years of anecdotal reports about low-power laser stimulating skin or hair growth. (Yes, at the same time high-power lasers do the opposite.) Something about laser light stimulates certain biological pathways in cells. Scientists have now figured what that something is when it comes to dentin. A blast of laser induces reactive oxygen species, which are chemically active molecules that then activate a growth factor to stimulate dentin growth.

Although studies have regenerated parts of a tooth from stem cells in a petri dish before, the laser procedure can happen right in the mouth. This study’s authors got it to work in tiny rodent teeth, and now they’re continuing onto human clinical trials in hope it could someday replace some current dental procedures. I don’t know if the thought of even low-power lasers makes the dentist less terrifying, but I’d take it over a root canal. [Science Translational Medicine]

Bioengineers have come up with an implantable sponge made of silk that they say can be used to engineer and regenerate soft tissue like skin and fat. Because it is a biocompatible and biodegradable porous material, the sponge can act like a scaffold that can be loaded with therapeutic stem cells or drugs and inserted into tissue after damage from injury or disease. 

The Tufts University team that developed it sees the silk as a possible aid to spur healing after tumors are removed or a major traumatic injury. Read the paper that was published in the journal ACS Biomaterials Science & Engineering and click below to watch the video describing the innovation.

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Scientists grow teeth from human urine because why the hell not

A new study shows that stem cells extracted from urine can be turned into rudimentary tooth-like structures. Oh, and the researchers did so by growing the teeth inside the kidneys of mice.

To make the teeth, Duanqing Pei, who works at the Chinese Academy of Sciences in Guangzhou, mixed the stem cells with the connective tissue cells of mice. This concoction was grown for two days prior to being implanted under the outer layer of a mouse’s kidney. Once there, the cells were coaxed into becoming dental epithelial tissue, and eventually enamel.

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Working animal limb created in a lab

A new report details how a rat forelimb was able to be created in a lab, and have shown evidence that the same procedure could be used for the limbs of primates.

The limb was’t created from scratch, rather living cells from a donor forelimb were stripped down to a ‘matrix’ and then repopulated with progenitor cells from the recipient. This technique avoids risks from traditional donor transplants, where the recipient faces a life of immunosuppressive therapy to avoid the transplant being rejected.

The same decellularization process used in the whole-organ studies – perfusing a detergent solution through the vascular system – was used to strip all cellular materials from forelimbs removed from deceased rats in a way that preserved the primary vasculature and nerve matrix. After thorough removal of cellular debris – a process that took a week – what remained was the cell-free matrix that provides structure to all of a limb’s composite tissues. At the same time, populations of muscle and vascular cells were being grown in culture.

The research team then cultured the forelimb matrix in a bioreactor, within which vascular cells were injected into the limb’s main artery to regenerate veins and arteries. Muscle progenitors were injected directly into the matrix sheaths that define the position of each muscle. After five days in culture, electrical stimulation was applied to the potential limb graft to further promote muscle formation, and after two weeks, the grafts were removed from the bioreactor. Analysis of the bioartificial limbs confirmed the presence of vascular cells along blood vessel walls and muscle cells aligned into appropriate fibers throughout the muscle matrix.

Functional testing of the isolated limbs showed that electrical stimulation of muscle fibers caused them to contract with a strength 80 percent of what would be seen in newborn animals. The vascular systems of bioengineered forelimbs transplanted into recipient animals quickly filled with blood which continued to circulate, and electrical stimulation of muscles within transplanted grafts flexed the wrists and digital joints of the animals’ paws. The research team also successfully decellularized baboon forearms to confirm the feasibility of using this approach on the scale that would be required for human patients.

Bioengineers put human hearts on a chip to aid drug screening

When University of California, Berkeley, bioengineers say they are holding their hearts in the palms of their hands, they are not talking about emotional vulnerability.    

Instead, the research team led by bioengineering professor Kevin Healy is presenting a network of pulsating cardiac muscle cells housed in an inch-long silicone device that effectively models human heart tissue, and they have demonstrated the viability of this system as a drug-screening tool by testing it with cardiovascular medications.

This organ-on-a-chip, reported in a study to be published Monday, March 9, in the journal Scientific Reports, represents a major step forward in the development of accurate, faster methods of testing for drug toxicity. The project is funded through the Tissue Chip for Drug Screening Initiative, an interagency collaboration launched by the National Institutes of Health to develop 3-D human tissue chips that model the structure and function of human organs.

“Ultimately, these chips could replace the use of animals to screen drugs for safety and efficacy,” said Healy.

UC Berkeley researchers have created a ‘heart-on-a-chip’ that effectively uses human cardiac muscle cells derived from adult stem cells to model how a human heart reacts to cardiovascular medications. The system could one day replace animal models to screen for the safety and efficacy of new drugs. Credit: Photo by Anurag Mathur/Healy Lab

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Cloning a woolly mammoth? Might not be as crazy as you think.

Geneticist Hendrik Poinar is working on bringing the woolly mammoth back from the dead. In a talk at TEDxDeExtinction, he explains how scientists are extracting DNA from the remains of woolly mammoths preserved in permafrost.

From his talk:

If you had asked me ten years ago whether or not we would ever be able to sequence the genome of extinct animals, I would have told you, “It’s unlikely.” If you had asked whether or not we would actually be able to revive an extinct species, I would have said, “Pipe dream.”

But I’m actually standing here today, amazingly, to tell you that not only is the sequencing of extinct genomes a possibility, actually a modern-day reality, but the revival of an extinct species is actually within reach…

To learn more about the effort to sequence the woolly mammoth genome, watch the whole talk here>>

Interactive Bionic Man, featuring 14 novel biotechnologies
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The National Institute of Biomedical Imaging and Bioengineering has launched the “NIBIB Bionic Man,” an interactive Web tool that showcases cutting-edge research in biotechnology. The bionic man features 14 technologies currently being developed by NIBIB-supported researchers. Examples include a powered prosthetic leg that helps users achieve a more natural gait, a wireless brain-computer interface that lets people who are paralyzed control computer devices or robotic limbs using only their thoughts, and a micro-patch that delivers vaccines painlessly and doesn’t need refrigeration. (via Interactive Bionic Man, featuring 14 novel biotechnologies | KurzweilAI)