The woman suffered from damaged corneas, and she seemed to have no options if she wanted to regain her sight. Luckily, one of her doctors had heard of a surgery developed in the 1960s in Italy, and in widespread use in Japan. The patient's tooth becomes the scaffold for an artificial cornea.

According to the Miami Herald:

A tooth is used, [lead surgeon Victor] Perez said, because it provides a stable, living platform of tooth, bone and cartilage that can remain alive, get nutrition from the eye and grow into a single piece with the cornea . . . The multistage procedure began in March when Dr. Yoh Sawatari, a dental surgeon at the University of Miami Medical School, extracted the tooth — coincidentally, it was Thornton's eyetooth, also called the canine tooth — shaved it flat horizontally, drilled a hole in it and inserted an acrylic lens. He implanted the tooth/lens prosthesis under the skin inside her cheek, intending to leave it there for three months so the combination could heal together. Unfortunately, she developed a sinus infection, so he had to remove it and re-implant it under a pouch of skin in her upper chest.

Meanwhile, an eye surgeon removed scar tissue lining her damaged cornea.

A month later, surgeons removed a patch of skin from the inside of her cheek and laid it over her cornea to replace the moist tissue lost to the disease.

Two months after that, Perez extracted the tooth-lens combination from her chest, cut a flap out of the skin over the center of her cornea, cut a hole down into the eye and inserted the tooth-lens. He sewed the flap shut to hold in the tooth-lens and cut a tiny hole so the lens can protrude a couple of millimeters out of the eye.

via Miami-Herald

Yesterday at the massive BIO conference in Atlanta, company Fraunhofer-Gesellschaft showed off its new rapid skin development machinery (pictured).

This new skin differs from other tissue-engineered skin because its structure is exactly like what's on your body. It's got two layers made up of different cell types, while other manufactured skin tends to be one thin layer made up of only one type of cell. How does it work? According to Science Daily:

In a multi-stage process, first small pieces of skin are sterilized. Then they are cut into small pieces, modified with specific enzymes, and isolated into two cell fractions, which are then propagated separately on cell culture surfaces. The next step in the process combines the two cell types into a two-layer model, with collagen added to the cells that are to form the flexible lower layer, or dermis. This gives the tissue natural elasticity. In a humid incubator kept at body temperature, it takes the cell fractions less than three weeks to grow together and form a finished skin model with a diameter of roughly one centimeter. The technique has already proven its use in practice, but until now it has been too expensive and complicated for mass production.

That's all changing now. And the next step is to create skin that can be used for more than testing skin products. The killer app for this is clearly a skin that will be plug-and-play, completely ready to stick right onto your body. How will the researchers do that? By building blood vessels into their next generation skin.

Fraunhofer-Gesellschaft scientists are already working on human skin with blood vessels, and they report that the machines they use to automate tissue production should work on this version of their skin too. I would definitely be willing to pay 34 Euros for a skin replacement if I got injured. The question is, how long before this stuff is being sold over-the-counter for scrapes and cuts? Or, you know, to cover up those pesky rips that reveal your metal cyborg endoskeleton?

via Science Daily

This isn't to say that B and T cells will be forced to do our bidding. "The goal is to perturb the cell as little as possible," said Robert Cohen, one of the authors of the paper in Nano Letters. Each synthetic patch only covers a small part of the cell's surface, so the cell can still carry out its normal functions without disturbance.

In fact, "backpack" is a near-perfect analogy for this technology. The synthetic patch application consists of three layers of polyelectrolytes (certain types of polymers). Inside, the middle layer is whatever the scientists want the cell to be carrying: examples include a vaccine, a protein marker, or magnetic nanoparticles for controlled direction. The bottom layer of the patch is a polymer that attaches to the surface of the immune cell, and the top layer binds to other cells.

If you squint while you're watching this video (courtesy of MIT TechTV), the hordes of marauding B cells kind of look like ants with backpacks:

Now that we know human immune cells can carry a bit of extra load, it's time to start thinking about how we can use that capability to treat cancer or improve our bioimaging — or if you prefer, what kind of pencil boxes and notebooks will go into these new cellular backpacks.

Leaf-cutter ant image from Wikimedia Commons.
Surface-functionalized cell diagram courtesy American Chemical Society.

Tiny backpacks for cells [MIT News Office]
Surface functionalization of living cells with multilayer patches [Nano Letters]

Using laser microfabrication techniques, Freed and Engelmayr created a scaffold out of an elastic polymer called poly(glycerol sebacate) (PGS). Though there have been previous attempts to rebuild heart tissue in this way, their new approach has three key advantages that make it the best bet so far for broken hearts. First, they can control the stiffness of the PGS structure to match the mechanical properties of actual heart tissue. In addition, by exciting the tissue with electrical fields, they can encourage the growth of the scaffold in any direction they want. Plus, Freed and Engelmayr found that their PGS structure conformed naturally to the desired alignment of healthy cardiac cells — "the scaffold itself has an intrinsic ability to guide the orientation of cultured heart cells," says Freed. And as an added bonus, their growing structure looks really ridiculously cool:

Mending broken hearts with tissue engineering [MIT]
Accordion-like honeycombs for tissue engineering of cardiac anisotropy [Nature Materials]

Image by G.C. Engelmayr, Jr. of MIT.
Video courtesy of Macmillan Publishers Ltd.: Nature Materials, advance online publication, 02 November 2008 (doi: 10.1038/nmat2316).

According to Science Daily:

Hydrogels, which are considered to be the state-of-the-art in tissue design, are made from polymers that swell in water to form a gel-like material. They interact with growth factors much like demineralized bone matrix does, providing scaffolding for bone cells to proliferate and form new tissue.

Seems obvious that after this bone-growing scaffold is perfected for treating injuries that it would become the body modder's dream substance. People could grow Hellboy horns, protective chest plates, or foot bones that could withstand a lifetime of high-heeled shoes.

Hydrogels Provide Scaffolding for Growth of Bone Cells [via Science Daily]

The next steps could be transplanting these blood vessels, or using progenitor cells to grow vessels in engineered muscles or organs. According to the American Heart Association:

If researchers can develop ways to speed the growth of the vessels, non-surgical cardiac bypass procedures could potentially grow new vessels around those blocked by atherosclerosis.

[Lead researcher Joyce] Bischoff said other findings include:

* The cells created a vigorous network of vessels that connected to one another and to the vessels of the host mouse within seven days and continued to transport blood during the four-week study.

* Once combined and implanted, the two progenitor cells arranged themselves into vessels with minimal outside help, i.e., without any genetic alteration or manipulation to improve their growth. This is important because many growth-promoting genes are the same genes that become activated in cancer.

Eventually, predict researchers, Bischoff's technique could be used to treat cancer or heart disease. Imagine just regrowing an artery that had become clogged, or removing a tumor and replacing it with a chunk of tissue that already has healthy veins in it that can attach to your circulatory system.

Researchers Grow Human Blood Vessels in Mice [Eurekalert]

Attendees listened to talks with names like "What product features will influence an animal advocate's decision to move from vegetarianism to In Vitro Meat?" and went to panels devoted to "large-scale tissue engineering." While it's still more expensive to produce cultured meat than it is to raise chickens for the slaughter, the economics are changing as swiftly as the technologies to produce cultured meat. Mostly the barriers to market entry in a few years will be the meat industry itself, which may attempt to scare consumers away from the stuff or pull strings in government block the synthetic flesh via regulations.

For the record, cultured meat tastes just like regular meat — it's tissue-engineered muscle, made of exactly the same biological ingredients as meat from dead animals. It can also be a lot less fatty. Texture is one of the remaining issues, which is why proponents of cultured meat suggest it will first come to market as chicken nuggets and ground meat.

Andrew Revkin of the New York Times Dot Earth blog imagines vat meat as an eco-alternative:

But one could envision someday a model, say, of a solar-powered facility in southern California or Singapore basically turning sunlight and desalinated seawater into growth medium and then tons of cruelty-free, sustainable nuggets of chicken essence.

Whatever works best. If it is harder to move people [to stop slaughtering animals] on ethical grounds than it is to provide a sustainable humane substitute, I'm all for the substitute.

Can People Have Meat and a Planet Too? [Dot Earth]

Tissue engineered skin has been used on humans since 2001, though initially it was merely a replacement for cadaver skin as a temporary solution for burn patients whose skin was damaged too extensively to consider skin grafts. More permanent solutions designed to more closely mimic the structure of skin are on the way, with several different designs currently under research or in the clinic. We're a long way from a tissue engineered donor-free face transplant, but we'll get there. There are non-medical benefits to this work as well - a variation on tissue engineered skin called Episkin is being marketed in Europe as an alternative to animal testing of cosmetics.

One of the advantages of skin from an engineer's point of view is that it's easy to feed. Thin sheets do not require a system of blood vessels to supply the cells inside the sheet with adequate oxygen and fuel. Cartilage is another tissue that can do pretty well without a vasculature, and has a tendency to heal poorly - a combination that sends clinical researchers off to write grants. If you're looking at total knee replacement in the future, keep in mind that there's already one therapeutic alternative and several others in the works.

If you're a sports fan, at one time or another you've probably had your team's season imperiled by a player's torn ligament. While these lingering injuries may be a boon to broadcasters and sports writers, for athletes they can be career-ending events. A biodegradable polyester combined with cells from undamaged ligament may be the solution - in rabbit knees, these engineered ligament replacements already rival transplants. The thing about a transplant is, that transplant tissue has to come from somewhere. If from another body, you've got tissue rejection to look forward to. If from you, getting there requires a scalpel and seriously good painkillers. These engineered alternatives, using cells from the patient cultured outside of the body, do a lot less hurting to get to the healing.

Most bone breaks heal on their own with a little immobilization, but not all, and fractures aren't the only problem one can have with bone. A man in Finland lost his upper jaw to a tumor, but doctors were able to create a replacement. A biomaterial scaffold was created in the shape of the missing part, then seeded with mesenchymal stem cells from a culture of the cells in a sample of the patient's fat. The whole device was then implanted in the man's abdomen, where it was given nine months to develop before being removed and implanted into the jaw. That may sound a little roundabout, but considering the only other option was hacking enough bone out of the man's leg to rebuild the jaw, you can see the attraction. Similar work has been done in Germany using the patient's back as an incubator instead of the abdomen, giving you a potential choice of scars as well.

If that same fellow ended up a few teeth shy, or you're worried about encroaching denturehood, engineered teeth are possible as well - in mice. Until it's working in humans, I strongly suggest you floss regularly.

There's a lot of exciting work in kidneys, but if you know any potential donors try and stay on their good side. There are already a few tissue engineered bladders engaged in their usual duties inside patients.

Heart disease is a leading cause of death in the United States, and to some, the holy grail of tissue engineering. Replacing clogged blood vessels or valves with healthy engineered tissue would save lives and wear and tear on the parts of the body where we usually go scrounging for healthy vessels to replace the damaged bits with. It doesn't get much tricker than a complete engineered heart transplant - a machine that requires incredible timing, physical power, a highly specific vasculature, and most importantly, a vanishingly small failure rate. One approach is to cheat - that is, take an existing donor heart and remove all of the cells, leaving the structure intact. The deheartinated hearts are then seeded with heart cells from the would-be patient. Rat hearts treated in this manner can be coaxed into beginning to beat anew, though as of yet not hard enough to replace an ailing ticker.

Do you have questions you've always wanted to ask a biogeek? You can email me at tdj@io9.com.