News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

Standard chemotherapies may efficiently kill cancer cells, but they also pose significant risks to healthy cells, resulting in secondary illness and a diminished quality of life for patients. To prevent these risks, researchers led by Penn State have developed a new class of nanomaterials engineered to capture chemotherapy drugs before they interact with healthy tissue. The method is based on hairy cellulose nanocrystals – nanoparticles developed from the main component of plant cell walls and engineered to have large numbers of polymer chain "hairs," extending from each end.

When sheets of graphene are stacked, electrons begin to interact not only with other electrons within a graphene sheet, but also with those in the adjacent sheet. Changing the angle of the sheets with respect to each other changes those interactions, giving rise to interesting quantum phenomena like superconductivity. Now, a research team from Brown University has shown that when two sheets of graphene are stacked together at a particular angle with respect to each other, the bilayer graphene becomes a powerful ferromagnet.

Although twisted sheets of double bilayer graphene have been studied extensively in the past few years, there are still pieces missing in the puzzle that is its phase diagram – the different undisturbed, ground states of the system. Now, an international team of researchers has found a new puzzle piece: an electronic nematic phase. A nematic phase occurs when particles in a material break an otherwise symmetrical structure and come to loosely orient with one another along the same axis. This phenomenon is the basis of the liquid-crystal display commonly used in televisions and computer monitors. 

Researchers at Johns Hopkins Medicine have developed a color-coded test that quickly signals whether newly developed nanoparticles deliver their cargo into target cells. Historically, nanoparticles have a very low delivery rate to the cytosol, the inside compartment of cells, releasing only about 1%–2% of their contents. The new testing tool, engineered specifically to test nanoparticles, could advance the search for next-generation biological medicines.

Researchers at Cornell University were surprised to find that the three-dimensional semiconductor particles can possess the electronic properties of two-dimensional materials – a finding that had never been envisioned and could not have been revealed without high-resolution imaging. This discovery could be leveraged for solar energy conversion technologies and could benefit renewable energy technologies that reduce carbon dioxide, convert nitrogen into ammonia, and produce hydrogen peroxide.

A team of scientists from Harvard University and Nanyang Technological University in Singapore has developed a “smart” food packaging material that is biodegradable, sustainable, and kills harmful bacteria. The water-proof food packaging is composed of nanofibers – formed by electrospinning cellulose nanocrystals, a type of corn protein called zein, and starch – infused with a cocktail of natural antimicrobial compounds. When exposed to an increase in humidity or enzymes from harmful bacteria, the nanofibers release the natural antimicrobial compounds, killing common dangerous bacteria that contaminate food, such as E. Coli and Listeria, as well as fungi.

Researchers at the University of Pennsylvania have investigated how neutrophils – the white blood cells responsible for detecting and eliminating harmful particles in the body – are able to differentiate between bacteria and other compounds in the bloodstream, such as cholesterol particles. They tested a library consisting of 23 different protein-based nanoparticles, which revealed a set of "rules" that predict uptake by neutrophils. Neutrophils don't take up symmetrical, rigid particles, such as viruses, but they take up nanoparticles that exhibit "protein clumping." 

Researchers at Northwestern University and the Toyota Research Institute have successfully applied machine learning to guide the synthesis of new nanomaterials. The highly trained algorithm combed through a defined dataset to accurately predict new structures that could fuel processes in clean energy and in chemical and automotive industries.

Researchers at Rice University have calculated how strains and stresses affect both individual nanotubes and those assembled into fibers. They found that while nanotube fibers can fail under cyclic loads over time, nanotubes may remain perfect. The researchers hope to give other researchers and industry a way to predict how long nanotube fibers and other assemblies can be expected to last under given conditions.

Physicists at the University of Nebraska–Lincoln have shown that antiferromagnets can be used to store and process data in a way that would complement the digital electronics that are currently used in cell phones and computers. Antiferromagnets are a type of material that generate virtually no net magnetic field. In contrast, most spintronic memory components so far have relied on ferromagnets – materials with a permanent magnetic field. This discovery reveals that similar to ferromagnets, antiferrromagnets could be used to make nanometer-scale components of computer storage devices, and such devices would store and process data much faster than current storage devices.