Dan Luo, Ph.D

Clay – a seemingly infertile blend of minerals – might have been the birthplace of life on Earth. Or at least of the complex biochemicals that make life possible, Cornell biological engineers report in the Nov. 7 online issue of the journal Scientific Reports, published by Nature Publishing.

“We propose that [in early geological history] clay hydrogel provided a confinement function for biomolecules and biochemical reactions,” said Dan Luo, professor of biological and environmental engineering and a member of the Kavli Institute at Cornell for Nanoscale Science.

In simulated ancient seawater, clay forms a hydrogel – a mass of microscopic spaces capable of soaking up liquids like a sponge. Over billions of years, Luo explained, chemicals confined in those spaces could have carried out the complex reactions that formed proteins, DNA and eventually all the machinery that makes a living cell work. Clay hydrogels could have confined and protected those chemical processes until the membrane that surrounds living cells developed, he said.

Cornell researchers Jenny Sabin, assistant professor of architecture, and Dan Luo, professor of biological and environmental engineering, are among the lead investigators on a new research project to produce “buildable, bendable and biological materials” for a wide range of applications.

Sabin and Luo will share in a $2 million, four-year National Science Foundation grant with University of Pennsylvania researchers Randall Kamien, physics, and Shu Yang, materials science.

The project is intended to bring new ideas, motifs, portability and design to the formation of intricate chemical, biological and architectural materials.

Based on Kirigami (from the Japanese word kiru, “to cut”), the project “offers a previously unattainable level of design, dynamics and deployability” to self-folding and unfolding materials from the molecular scale to the architectural level, according to the researchers.

The research will include cutting and joining nano-sized DNA-polymer hybrids, 3-D printing and geometric models on the macroscopic scale.

A bit reminiscent of the Terminator T-1000, a new material created by Cornell researchers is so soft that it can flow like a liquid and then, strangely, return to its original shape.

Rather than liquid metal, it is a hydrogel, a mesh of organic molecules with many small empty spaces that can absorb water like a sponge. It qualifies as a “metamaterial” with properties not found in nature and may be the first organic metamaterial with mechanical meta-properties.

Hydrogels have already been considered for use in drug delivery — the spaces can be filled with drugs that release slowly as the gel biodegrades — and as frameworks for tissue rebuilding. The ability to form a gel into a desired shape further expands the possibilities. For example, a drug-infused gel could be formed to exactly fit the space inside a wound.

Dan Luo, professor of biological and environmental engineering, and colleagues describe their creation in the Dec. 2 issue of the journal Nature Nanotechnology.

Two Cornell professors will combine their inventions to develop a handheld pathogen detector that will give health care workers in the developing world speedy results to identify in the field such pathogens as tuberculosis, chlamydia, gonorrhea and HIV.

Using synthetic DNA, Dan Luo, professor of biological and environmental engineering, has devised a method of “amplifying” very small samples of pathogen DNA, RNA or proteins. Edwin Kan, professor of electrical and computer engineering, has designed a computer chip that quickly responds to the amplified samples targeted by Luo’s method. They will combine these to make a handheld device, usable under harsh field conditions, that can report in about 30 minutes what would ordinarily require transporting samples to a laboratory and waiting days for results.

The work will be supported by the Bill & Melinda Gates Foundation as part of the Grand Challenge program to develop “point-of-care diagnostics” for developing countries. The foundation has distributed $25 million to 12 teams, selected from more than 700 applicants. Various teams are working on different aspects of the technology, and eventually their work will be integrated to make a practical, low-cost testing kit, Luo said.

DNA isn’t just for genetics anymore. Cornell researchers are using synthetic DNA to make nanoparticles, dubbed DNAsomes, that can deliver drugs and genetic therapy to the insides of cells.

Dan Luo, professor of biological and environmental engineering, and colleagues report their work in the Jan. 3 issue of the journal Small.

DNAsomes, Luo said, can carry multiple drugs as well as RNA molecules designed to block the expression of genes, an improvement over other drug-delivery systems such as liposomes (tiny wrappers of the phospholipid molecules that make up cell membranes) or polymer nanoparticles. Also, some other delivery systems can be toxic to cells, the researchers said.

In its natural habitat in the nucleus of a cell, DNA consists of long chain molecules that are complementary, attaching to one another like a string of Lego blocks over their entire length to form the famous double helix. The Luo research group creates short chains of synthetic DNA designed to attach over only part of their length so they will join into shapes like crosses, Ts or Ys.

Dan Luo, associate professor of biological and environmental engineering, has been selected to receive the 2010 Journal of Materials Chemistry Editorial Board Award, which honors a younger scientist who has made a significant contribution to the materials chemistry field. Luo will be the first recipient of the new award, which will be given annually.

In connection with the award, Luo is invited to contribute an article to the journal, published by the Royal Society of Chemistry in England, and to give three lectures at upcoming conferences describing his research. The award includes a stipend to cover the cost of travel to these events.