NEWS OF THE WEEK ALTERNATIVE
ENERGY
SOLAR ENERGY NEEDS MAJOR PUSH DOE says considerable research is required to improve solar energy UNLIGHT COULD PROVIDE
S SUN CATCHER Research is needed to develop solar energy as a significant source of renewable energy.
a clean, abundant source of energy in the future, but a major research effort is needed to close the huge gap between the current use of solar energy and its enormous undeveloped potential, government scientists say in a new report. World demand for energy is projected to more than double by 2050 and to more than triple by the end of the century, notes the study by the Department of Energy. It says incremental improvements in existing energy networks will not be adequate to
DRUG
supply this demand in a sustainable way "Finding sufficient supplies of clean energy for the future is one of society's most daunting challenges," notes the report, which outlines the basic research needed to increase the use of solar and other renewable forms of energy "This report demonstrates the important contribution the entire scientific community can make to the development of new sustainable energy resources," says Raymond L. Orbach, director of DOE's Science Office. "Science and basic research can and
DELIVERY
HYDROGEL RELEASES DRUG IN TWO STEPS Delivery system relies on low-molecularweight hydrogel and enzyme
A
HYDROGEL-DRUG SYSTEM
that relies on the consecutive action of two trigger mechanisms to release a drug has the potential to target specific sites within the body according to the scientists in the Netherlands who developed the system. The triggers are a stimulus that converts
HYDROGELDRUG System comprises a gelator scaffold (blue), linker (green), and model drug (red). 12
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the gel into a solution and an enzyme that cleaves the hydrogelator-drug link. "Raising the temperature or lowering the p H causes more lowmolecular-weight gelator molecules to come out of the gel fibers and go into solution," says Kjeld J. C van Bommel, a researcher at Biomade Technology Foundation, Groningen, who carried out the work with Jan van Esch, assistant professor of chemistry at the University of Groningen, and coworkers (Org. Biomol. Chem. 2005,3,2917). "Only when they are in solution can the molecules be cleaved by an enzyme and the drug be released," van Bommel continues.
must play a key role in addressing the energy security needs of our nation." Orbach says tax credits in the energy bill passed by Congress last month will greatly expand the use of renewable energy 'This research will help improve a critical component of renewable energy— solar technology—in the future," he says. "Increasing the use of renewable energy is a clearway to help meet our growing energy needs." According to the report, the proposed research could lead to artificial "molecular machines" that turn sunlight into chemical fuel; "smart materials" based on nature's ability to transfer captured solar energy with no energy loss; more efficient solar cells created using nanotechnologies; and new materials for high-capacity, slow-release thermal storage. The report is available at www.doe. gOV.-GLENN HESS
"The combination of a low-molecular-weight gelator gel sensitive to both its environment and enzymes is unique. It demonstrates that such systems are viable for controlled drug delivery" T h e system devised by the group makes use of a cyclohexane trisamide gelator compound covalently connected to a model drug. The compound gels in water to form a dense network of long, straight, unbranched tubular fibers that protect the drug moiety from enzymatic cleavage before release. The group used 6aminoquinoline as a model drug to demonstrate proof-of-concept of the system. The system has advantages over other two-stage drug delivery systems such as polymeric gelator systems, says the team. First, the gels have rapid response times—on the order of a few seconds—that are not attainable by polymeric systems. In addition, the enzymatic cleavage of the gelator-drug linker is specific for the linker bonds.— MICHAEL FREEMANTLE
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