Friday, July 30, 2010

This week in nanotechnology - July 30, 2010

Spotting a single cancerous cell that has broken free from a tumor and is traveling through the bloodstream to colonize a new organ might seem like finding a needle in a haystack. But a new imaging technique from the University of Washington is a first step toward making this possible. Researchers have developed a multifunctional nanoparticle that eliminates the background noise, enabling a more precise form of medical imaging – essentially erasing the haystack, so the needle shines through.

Imagine a device the size of – and nearly as cheap as – a grain of sand which is capable of analyzing the environment around it, recognize its chemical composition, and report it to a monitoring system. Researchers have now demonstrated a method to design prospective simple sensing arrays - so-called electronic noses - which, in principle, might be scaled down to the size of few micrometers and thus become the smallest analytical instrument.

First step towards electronic DNA sequencing: Translocation through graphene nanopores. Researchers at the University of Pennsylvania have developed a new, carbon-based nanoscale platform to electrically detect single DNA molecules. Using electric fields, the tiny DNA strands are pushed through nanoscale-sized, atomically thin pores in a graphene nanopore platform that ultimately may be important for fast electronic sequencing of the four chemical bases of DNA based on their unique electrical signature.

atomically-thin graphene nanopores

Electric fields push tiny DNA strands through atomically-thin graphene nanopores that ultimately may sequence DNA bases by their unique electrical signature.

By linking individual semiconductor quantum dots with gold nanoparticles, scientists have demonstrated the ability to enhance the intensity of light emitted by individual quantum dots by up to 20 times. The precision method for making the light-emitting particle clusters will greatly advance scientists' ability to study and modify the optical properties of quantum dots, and could eventually lead to improved solar energy conversion devices, light-controlled electronics, and biosensors.

Using chemical "nanoblasts" that punch tiny holes in the protective membranes of cells, researchers have demonstrated a new technique for getting therapeutic small molecules, proteins and DNA directly into living cells.

Numerous pathogens can cause bloodstream infections (sepsis) and the most straightforward cure is to remove the disease-causing factors from a patient's blood as quickly as possible. By using metal nanomagnets carrying target-specific ligands, researchers at ETH Zurich have shown that blood purification at a nano- to pico-molar scale is possible.

Researchers report the creation of pseudo-magnetic fields far stronger than the strongest magnetic fields ever sustained in a laboratory – just by putting the right kind of strain onto a patch of graphene. They show that when graphene is stretched to form nanobubbles on a platinum substrate, electrons behave as if they were subject to magnetic fields in excess of 300 tesla, even though no magnetic field has actually been applied.

 graphene nanobubble

In this scanning tunneling microscopy image of a graphene nanobubble, the hexagonal two-dimensional graphene crystal is seen distorted and stretched along three main axes.