Liver cells thrive on novel silicon chips. (Science News of the week).In a feat that could lead to new medical treatments, researchers have grown healthy liver cells on silicon chips.
Called a "liver bioreactor bioreactor
a container in which living organisms carry out a biological reaction. ," the apparatus consists of a chip of spongelike silicon with pores just 2 to 1,500 nanometers wide. The research team, from the University of California, San Diego UCSD is consistently ranked among the top ten public universities for undergraduate education in the United States by U.S. News & World Report. It is a Public Ivy.  For graduate studies, most of UCSD's Ph.D. (UCSD UCSD University of California, San Diego (La Jolla, California)
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The liver's primary cells, hepatocytes, are notoriously hard to culture. But when grown in the bioreactors, thousands of the cells functioned normally throughout a 2-week trial, the researchers reported last week in San Diego at a meeting of the American Chemical Society The American Chemical Society (ACS) is a learned society (professional association) based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has over 160,000 members at all degree-levels and in .
Pores of certain sizes provide a texture on which cells thrive, graduate student Vicki Chin found. "It's kind of like the Goldilocks gold·i·locks
pl.n. (used with a sing. or pl. verb)
A European plant (Aster linosyris) having narrow sessile leaves and dense corymbs of small, bright yellow, discoid flower heads. principle," says chemist Michael J. Sailor, a member of the team. "Some of these holes are too big, some too small, and some are just right."
Pores may also allow the transfer of nutrients between cells while keeping out large objects, such as bacteria, suggest the researchers.
It might be possible to exploit silicon's electronic properties by building sensors and other components directly into the bioreactor. Such a device could monitor the cells' health, says Sailor, whose lab made the porous chips under the direction of UCSD researcher Boyce E. Collins. "We want to have some way for these cells to report to us and tell us whether they're happy or not," says Sailor.
Integrating microelectronics and bio-medicine to read cellular signals and to respond appropriately, such as with a drug dose, is "the Holy Grail of this field," says engineer Philippe M. Fauchet, director of the Center for Future Health at the University of Rochester The University of Rochester (UR) is a private, coeducational and nonsectarian research university located in Rochester, New York. The university is one of 62 elected members of the Association of American Universities. in New York.
Efforts to combine cells with porous silicon received a boost in the mid-1990s. That's when Leigh Canham of the British defense-research agency DERA DERA Defence Evaluation and Research Agency (UK)
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"Silicon, surprisingly, is an ideal material for a new generation of reactors," says Sangeeta N. Bhatia, a physician and bio-engineer on the UCSD team.
Bhatia hopes that such bioreactors eventually could become the basis of artificial livers. "Porous silicon is quite attractive as a biodegradable scaffold" on which such an organ replacement could be built, adds Canham, who has just joined a company developing biologically compatible silicon structures.
By 2010, the worldwide incidence of the hepatitis C infection-probably will overtake that of HIV HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. , says Bhatia. Yet the standard treatment for liver disease is transplantation, and fewer livers are available than are needed now, she says.
Bhatia suspects that the first use of the bioreactor might be for testing pharmaceuticals' toxicity, potentially even replacing laboratory animals, Bhatia says.
Fauchet says that such testing would help speed the screening of drug candidates. One potential pitfall to consider, he cautions, is that subtle changes in cells grown on silicon may not necessarily reflect the behavior of comparable cells in the body.