Tag: ‘Biotech’

Artificial bones made with 3D inkjet printers

13 Aug 2007

Custom artificial bone made on 3D inkjet printer -- Researchers from the Tissue Engineering Department at the University of Tokyo Hospital and venture company Next 21 are using 3D inkjet printers to produce tailor-made artificial bones for use in facial reconstructive surgery. Following initial trials performed on a Welsh corgi and 10 people over the past year and a half, the researchers are set to begin a more extensive second round of human testing this autumn.

To make an artificial bone with this technology, a 3D computer model of the bone is first created based on the patient's X-ray and CT scan data. The computer model is then sliced into a large number of cross-sections and the data is sent to a special 3D inkjet printer, which works sort of like an ordinary inkjet printer by transferring tiny droplets of liquid onto a surface. However, unlike ordinary printers that print on paper, this one prints onto thin layers of powdered alpha-tricalcium phosphate (alpha-TCP). The "ink" is a water-based polymer adhesive that hardens the alpha-TCP it comes into contact with. By repeatedly laying down the powder and printing successive layers on top of one another, the printer is able to physically reproduce the desired bone to an accuracy of one millimeter.

Strong, lightweight and porous, the printed bones have characteristics similar to natural bone, and because they are tailored to fit exactly where they need to go, they are quick to integrate with the surrounding bone. The printed bone is also designed to be resorbed by the body as the surrounding bone slowly grows into it and replaces it.

In initial human trials conducted between March 2006 and July 2007, the effectiveness and safety of the artificial bones were tested in plastic surgery operations performed on 10 male and female patients between the ages of 18 and 54. In the second round of trials beginning this autumn at 10 medical institutions across Japan, the researchers plan to print up and implant synthetic bones in 70 volunteer patients with face or skull bones that have been damaged or removed due to injury or surgery.

While the printed bones are still not considered strong enough to replace weight-bearing bones, they are ten times stronger than conventional artificial bones made from hydroxylapatite, a naturally occurring mineral that is also the main component of natural bone. The printed bones are also cheaper and easier to make than hydroxylapatite implants, which must be sintered, or heated to a high temperature to get the particles to adhere to each other. In addition to taking longer to produce, sintered implants also take longer for the body to resorb.

The next round of human trials will be conducted at Dokkyo Medical University, Saitama Medical University, Tokyo Dental College, University of Tokyo, Juntendo University, Tsurumi University, Kyoto University, Osaka Medical College, Kobe University and Osaka City General Medical Center.

The researchers hope to make the technology commercially available by 2010.

[Source: Fuji Sankei, The Chemical Daily]

Fourth-generation pig clones born

07 Aug 2007

Fourth-generation clone piglets ---

In a development that brings us one step closer toward the mass-cloning of animals for use in regenerative medicine, researchers from Meiji University have succeeded in creating the world's first fourth-generation pig clones.

Since creating a pair of pig clones in April 2004, professor Hiroshi Nagashima, the research team leader, has been recloning the clones using cells from their salivary glands. The fourth-generation piglets -- three of them born on July 23 -- are clones of clones of clones of clones, so they share the exact DNA as the original pig.

Scientists have been seeking to advance pig cloning technology because pig organs are physiologically similar to human organs, meaning they could be the key to alleviating the worldwide shortage of organs for transplant.

Past examples of animals that have been cloned through multiple generations include mice, which have been recloned up to the sixth generation, and cows, which have been recloned to the second generation. While recloning technology may promise to boost the productivity of cloning operations, there are some drawbacks. For instance, in somatic cell nuclear transfer -- a reproductive cloning technique where the nucleus from a donor adult cell (somatic cell) is transferred to a nucleus-free egg cell, which is then transferred into the uterus of a surrogate mother -- DNA damage accumulates with each generation that is cloned. After a number of generations, the cumulative damage to the DNA could result in an animal that is significantly different from the original.

So far, however, the fourth-generation pig clones show no signs of abnormalities, and the researchers are planning to reclone them again.

In addition to creating the world's first fourth-generation pig clones, Nagashima's team also reported success in using a combination of gene transfer technology and cloning technology to create transgenic diabetic pigs -- pigs with human genes that exhibit symptoms of diabetes mellitus. The researchers worked with BIOS Inc., a venture company based in Kanagawa prefecture, to engineer the pigs.

While we have seen transgenic diabetic mice in the past, these transgenic diabetic pigs are reportedly the first of their kind. With the anatomical similarities between man and swine, transgenic diabetic pigs could lead to a cure for diabetes by helping scientists develop transplant technology involving the use of pig pancreatic tissue, a potential source of insulin. In addition, the pigs can also serve as models for observing the complications associated with diabetes, such as arteriosclerosis, and they could help researchers develop new medicines.

Professor Nagashima suggests that in addition to serving as model animals for human diseases, individuals will be able to use their own cells in these bioengineered pigs to test the effectiveness and safety of regenerative medicine therapies.

[Source: Yomiuri, Jiji]

Artificial blood vessels made from salmon skin

12 Mar 2007

Artificial blood vessels made from salmon skin --- Researchers from Hokkaido University have created artificial blood vessels using collagen derived from the skin of salmon. The researchers, who replaced the aortas of rats with the artificial blood vessels, claim to be the first to create and successfully test artificial blood vessels made using collagen derived from marine animals.

The researchers decided to use salmon skin for regenerative medicine applications after seeing large amounts of the skin go to waste in local seafood processing operations. On Japan's northern island of Hokkaido, seafood processors discard about 2,000 tons of salmon skin each year -- enough to yield an estimated 600 tons of collagen. In addition, there are no known viruses transmitted from salmon to humans, so the use of salmon collagen is regarded as relatively safe. Scientists have created artificial tissue from bovine (cow) and porcine (pig) collagen in the past, but there have always been concerns over the possible transmission of infectious diseases such as BSE (mad cow disease).

One problem the researchers faced early on was the salmon collagen's poor resistance to heat. Because salmon collagen ordinarily melts at about 19 degrees Celsius (66 degrees Fahrenheit), it could not be used as a tissue replacement in humans. But by developing a process that forms the collagen into fibers and strengthens the bonds between molecules, the researchers were able to raise the melting point of the collagen to 55 degrees Celsius (131 degrees Fahrenheit).

The heat-resistant collagen was used to create blood vessels with an internal diameter of 1.6 mm and a wall thickness of 0.6 mm. When grafted into rats, the artificial blood vessels demonstrated the ability to expand and contract along with the heartbeat, and they were shown to be as strong and elastic as the original aortas.

Nobuhiro Nagai, from Hokkaido University, says the researchers plan to test the blood vessels in larger animals such as dogs. One day they hope to see their biomaterial used in humans as a replacement for damaged blood vessels, he says.

The research results are set to be announced at a meeting of the Japanese Society for Regenerative Medicine (JSRM), which is scheduled to begin in Yokohama on March 13.

[Source: Mainichi]

Instant bonsai

19 Jan 2007

Mini-petunias (top left) and ordinary petunias -- On January 18, researchers from Japan's Institute of Physical and Chemical Research (RIKEN) and the University of Michigan announced the development of a technique for engineering "mini-plants" that are 1/10th their ordinary size.

The researchers claim it is possible to tailor the size of plants by manipulating the genes that regulate the activity of growth hormones. The technique is expected to lead to the creation of miniaturized versions of decorative houseplants, as well as dwarf crops that are easier to harvest and more resistant to wind damage.

In studying dwarf varieties of rice and wheat created through ordinary hybridization, the researchers found damage to the genes that synthesize gibberellin, a growth hormone. When researchers looked for a mechanism to control the growth hormone, they discovered that the GAMT1 and GAMT2 genes commonly found in plants were responsible for producing an enzyme that neutralizes gibberellin.

When the researchers engineered strains of petunias and thale cress (Arabidopsis thaliana) in which the two genes were constantly expressed, the plants grew to 1/10th their ordinary size. When plants were administered gibberellin, they grew to their normal size, demonstrating that the size of plants can be freely adjusted.

[Source: Yomiuri]

Sweet wheat

18 Dec 2006

Sweet wheat -- On December 12, researchers from Japan's National Agriculture and Food Research Organization (NARO) and Nippon Flour Mills announced the development of sweet wheat, a hybridized variety of wheat with twice the sugar concentration of common wheat. This first-of-its-kind sweet wheat eliminates the need to add sugar when it is used in cakes or other baked goods, researchers claim.

By repeatedly breeding varieties of wheat with low levels of enzymes associated with starch production, the researchers were able to lower the wheat's starch content -- which is ordinarily around 70% -- to 25%. The result is a variety of wheat with a significantly higher concentration of sugars such as maltose and sucrose.

In this way, sweet wheat is similar in concept to sweetcorn, which also was specifically bred to increase its sugar content.

Sweet wheat is identical in appearance to common wheat, except that it withers and develops wrinkles when dehydrated. Its natural sweetness gives it a distinctive flavor when it is ground into flour and used as an ingredient in baked goods.

Nippon Flour Mills hopes to make sweet wheat commercially available in two to three years. In the meantime, the company is looking into the possibility of developing new types of food products that draw upon the natural flavor of sweet wheat.

[Source: Chunichi, Yomiuri]

Micromotor harnesses the power of bacteria

30 Aug 2006

Bacteria-powered motorResearchers from Japan's National Institute of Advanced Industrial Science and Technology (AIST) have developed a micromotor powered by the movement of bacteria.

The 20-micron (1 micron = 1 millionth of a meter) diameter revolving motor has 6 blades, each with a foot that sits in a 0.5-micron deep, 13-micron diameter groove etched into a silicon substrate. The surfaces of the feet and the groove are treated with proteins that cause the bacteria (introduced via a connecting groove) to move in one direction, pushing the feet (and spinning the motor) as they pass through the groove.

The researchers believe microbial motion can be harnessed as a power source for microdevices in the future, with potential applications that include motors for micromachines and miniature pumps for tiny medical devices.

The research results were published in the August 28 edition of PNAS (online edition).

[Source: Sanyo Shimbun, Jiji]

The bioluminescent tail of Genji

16 Mar 2006

Scientists have succeeded in unraveling the mystery -- at the protein structure level -- of the mechanism at work in the glowing tail of the "Genji firefly" (Luciola cruciata Motschulsky), which is considered to have the highest luminous efficiency of any known source of light. The results of the joint research carried by the Institute of Physical and Chemical Research (RIKEN) and Kyoto University are to be published in the March 16 edition of the British science journal Nature.


By tinkering with the chemical composition of luciferase (a bioluminescent enzyme), the research team succeeded in changing the emission color from its normal greenish-yellow to orange and red. Researchers are now attempting to recreate the blue glow of the sea firefly (Vargula hilgendorfii) and firefly squid (Watasenia scintillans) in order to have all three primary colors at their fingertips.

"This might prove useful in applications such as short-term emergency lighting when no source of electricity or combustion is available," says Kyoto University professor Hiroaki Kato. "Light could be created by mixing up a liquid protein solution."

Anytime energy is converted into light, there is some loss due to heat. Luminous efficiency is a measure of the proportion of energy supplied to a light source that is effectively converted into visible light energy (i.e. the amount not lost to heat or infrared radiation). The luminous efficiency of incandescent light bulbs is around 10%, while fluorescent light is around 20% and LED is around 30%. Firefly tails are significantly higher, at 90%. Scientists were aware that the Genji firefly used luciferase in combination with luciferin (a light-emitting substrate) and adenosine triphosphate (ATP) to produce light, but the detailed workings of the mechanism have until now remained a mystery.

[Sources: Jiji, RIKEN press release]