Study: Gold nanosensors could detect blood clots
Gold nanoparticles could accurately detect thrombin, a biomarker for blood clots in blood samples and could enable simple and highly sensitive monitoring tools for blood clots and other disorders, according to an article published online March 2 in the journal Chemical Communications.

Colin J. Campbell, Phd, EaStCHEM Research Fellow at the school of chemistry at the University of Edinburgh in Scotland, who led the research said, said: “By creating a sensor that can safely be implanted into tissue and combining this with a sensitive light-measurement technique, we have developed a useful device that will help diagnose and track disease in patients.”

The sensor consists of a silica core, 120 nanometers in diameter, encapsulated in a thin layer of gold. Mounted on the gold shell are aptamers, short strands of nucleic acids designed to bind to a specific molecular target. When a laser is shone, protein is detected through monitoring the surface enhanced Raman spectrum of the aptamer probe attached to a gold nanoshell.

"The gold particle works likes a kind of transducer for the laser," said Campbell. Using this technique, the researchers were able to detect sub-femtomolar concentrations of thrombin in human serum.

Michael Ochsenkühn, PhD student at the division of pathway medicine, University of Edinburgh, Scotland, and one of the researchers on the project are using the same technology to look at the biomolecular interactions involved in autoimmune disease. They are also investigating host-pathogen interactions for viral research. "You could actually locate in a cell what is happening at a particular time point in a viral infection," said Ochsenkühn.

Campbell's team had previously shown that the gold nanoshells appear safe when injected into cells--they don't cause cell death or impede new cell growth. As gold is unreactive, the body will not reject the implant, according to Campbell and colleagues. But the technology still has a number of hurdles to overcome before it can be used for medical applications.

"The limit of such research is it needs an aptamer that catches a specific protein," commented Jaebum Choo, PhD, professor at Hanyang University, Seoul, South Korea, who was not involved in the study. "While the thrombin aptamers are well known, few known aptamers for other proteins are known at this stage. For the development of this technology, biologists and biochemists need to find the various different kinds of aptamer for capturing valuable proteins."