Biology - Page 5

Researchers from Singapore's A*STAR institute and the US have designed a new way to pack molecule using graphene and graphone (graphene that is hydrogenated on one side) structures. The idea is to use a graphene sheet with a graphone domain that can be used to trap molecules. This is achievable because the graphone region is distorted in 3D to form a cap shape and it is stable well above room temperature.

In the research they used fullerenes as model molecules. It turns out that you can trap several molecules in the same graphone domain. This kind of structure can be useful for energy storage or biological applications.

Researchers from UT Dallas have managed to shrink the size of a graphene pore to less than one nanometer - small enough to thread a DNA strand. This can be useful for DNA sequencing.

The researchers used new technique to manipulate the size of the pore, by using an electron beam from an advanced electron microscope and in-situ heating up to 1200 degree Celsius temperature. They say that this is the first time that a graphene nanopore has been controlled. The next step is to build a prototype device to sequence DNA.

Aixtron announced today that Osaka University in Japan placed an order for a 4" AIXTRON BM Pro system. The University will use the new equipment to produce carbon nanotube (CNT) and graphene structures for bio-sensors. The aim is to combine graphene field-effect transistors with organic chemicals, such as antibodies, antigens and aptamers to allow electrical detection of specific proteins. The BM Pro system will also be used to produce carbon nanotubes for micro-electromechanical-systems (MEMS) and energy storage devices.

Some scientists are concerned that Graphene may be hazardous and toxic - for humans, animals and the natural environment. Researchers from Singapore's A*STAR have published a study on how graphite, graphite oxide, graphene oxide and reduced graphene oxide may effect bacteria (Escherichia coli in the study).

The researchers showed that the graphene-based materials kill substantially more bacteria than graphite-based materials. Graphene Oxide was the most dangerous material. The researchers say that most of the E.coli cells were individually wrapped by layers of graphene oxide. In contrast, E. coli cells were usually embedded in the larger reduced-graphene-oxide aggregates (see image above).

Researchers from Stony Brook University developed a new efficient graphene-based MRI contrast agent that's potentially safer and cheaper than current gadolinium-based agents. The new agent can also improve disease detection because of its sensitivity and diagnostic confidence.

Dr. Sitharaman, who led the research, has established a new company called Theragnostic Technologies which is set to commercialize this new agent.

Researchers suggest a new graphene based bio-sensor that can be used to detect bacteria and wirelessly transfer data. An example use case is putting it on tooth enamel. The graphene sensor is printed on water-soluble silk and can be "bio-transferred" on organic materials The silk is then dissolved in water and the sensor remains in place.

The device also includes an RFID tag, and is powered by tiny electric charges in the bacterial cell membranes.

Researchers at the University of Delaware suggest that graphene sheets with nanopores (tiny holes) could be used for ultrafast DNA sequencing based on tiny holes. The study which is based on computer simulation suggests that threading DNA though nanopores can be used to detect the presence of different DNA bases. This is done by a current of ions flowing vertically through the pore or an electronic current flowing transversely through the graphene.

Graphene is just one atom thick and so the nanopore has contact with only a single DNA base. The researchers suggest using nanoribbons of graphene to enable fast and low-cost (less than $1,000) DNA sequencing.

Researchers from the Juelich Research Center and the Technische Universitaet Muenchen developed a graphene-based transistor array that can record electrical signals generated by biological cells.

The team demonstrated an array of 16 graphene solution-gated field-effect transistors (G-SGFETs) - produced over a copper foil using standard photolithographic and etching and chemical vapor deposition processes. A biological cell layer analogous to the heart muscle was deposited directly over this array. The transistor array detected and recorded single cells' action potentials at high resolution.

Researchers from the University of Silesia in Poland are looking into using Graphene and Carbon nanotubes (CNTs) to remove excess cholesterol from living tissues. Using molecular dynamics (MD) simulations, the team says that a graphene sheet (of 720 carbon atoms), placed 2.3 nm from cholesterol-covered 1LQV protein significantly increased the mobility of the cholesterol molecules, reflecting their migration onto the graphene surface.

After this migration, a large number of cholesterol molecules were removed from the cluster surrounding the protein.

The following article was sent to us by Corey McCarren and Dr. Elena Polyakova from Graphene Laboratories (a Graphene-Info sponsor), discussing Graphene Oxide and its applications:

Graphene, a multi or single layer sheet of graphite, is considered a key material in producing the next generation of low-cost carbon-based transparent and flexible electronics. Graphene is the strongest material available, as well as being highly transparent, flexible, and the best conductor of heat and electricity. Great effort is devoted to developing an effective yet inexpensive way to produce graphene materials in industrial quantities.