Composite image of a fetus in utero.

Composite image of a fetus.

Doctor checking the pulse of the Amazon basin. Globe supplied by Hammond, Inc. .

Heart

heart injection

heart injection

lung bacteria

food pyramid set

Illustration of a man and a pie chart with a missing piece representing Alzheimer's Disease.

Conceptual image of petri dish with E-coli bacteria and a map of Africa, Europe and Asia, illustrating the spread of disease.

Conceptual image of petri dish with E-coli bacteria and a map of Asia and Australia, illustrating the spread of disease.

Conceptual image of petri dish with E-coli bacteria and a map of North and South America, illustrating the spread of disease.

Metal lungs with cigarette smoke.

In an achievement some see as the "holy grail" of nanoscience, an interdisciplinary research team at the U.S. Department of Energy's Brookhaven National Laboratory have for the first time used DNA to guide the creation of three-dimensional, ordered, crystalline structures of nanoparticles (particles with dimensions measured in billionths of a meter). The ability to engineer such 3-D structures is essential to producing functional materials that take advantage of the unique properties that may exist at the nanoscale - for example, enhanced magnetism, improved catalytic activity, or new optical properties. As with the group's previous work, the new assembly method relies on the attractive forces between complementary strands of DNA - the molecule made of pairing bases known by the letters A, T, G, and C that carries the genetic code of living things. First, the scientists attach to nanoparticles hair-like extensions of DNA with specific "recognition sequences" of complementary bases. Then they mix the DNA-covered particles in solution. When the recognition sequences find one another in solution, they bind together to link the nanoparticles. This first binding is necessary, but not sufficient, to produce the organized structures the scientists are seeking. To achieve ordered crystals, the scientists alter the properties of DNA and borrow some techniques known for traditional crystals. Importantly, they heat the samples of DNA-linked particles and then cool them back to room temperature, which allows the nanoparticles to unbind and reorganize for greater stabiltiy. The team also experimented with different degrees of DNA flexibility, recognition sequences, and DNA designs in order to find a "sweet spot" of interactions where a stable, crystalline form would appear.Results from a variety of analysis techniques, including small angle x-ray scattering at the National Synchrotron Light Source and dynamic light scattering and different types of optical spectroscopies and ele

Illustration of a pediatrician with a child patient.

Cross-section of a coronary artery showing plaque build-up and narrowing. Erythrocytes are squeezing forward and the heart is visible behind the artery.

Cross-section of a coronary artery showing plaque build-up and narrowing. Erythrocytes are squeezing forward and the heart is visible behind the artery.

Cross-section of a coronary artery showing plaque build-up and narrowing. Erythrocytes are squeezing forward and the heart is visible behind the artery.

Cross-section of a coronary artery showing plaque build-up, narrowing and clot, resulting in a myocardial infarction (heart attack).

Cross-section of a coronary artery showing plaque build-up, narrowing and clot, resulting in a myocardial infarction (heart attack).