‘Writing’ artificial membranes on graphene
23 Oct 2013 by Evoluted New Media
Graphene has emerged as a versatile new surface on which to assemble model cell membranes mimicking those in the human body, with potential applications in sensors, disease detection and drug screening.
Using Lipid Dip-Pen Nanolithography (L-DPN) researchers from the University of Manchester and the Karlsruhe Institute of Technology (KIT) have demonstrated that membranes can be directly written onto a graphene surface. Their work has been published in Nature Communications.
It is difficult to study bio-sensing, bio-catalysis and drug delivery using live cells inside the human body, so developing model membranes in surfaces outside the body is more convenient. The team – led by Manchester’s Dr Aravind Vijayaraghaven – have shown that graphene is an exciting new surface on which to assemble these models, and may have many advantages over current surfaces.
“Firstly, the lipids spread uniformly on graphene to form high-quality membranes. Graphene has unique electronic properties; it is a semi-metal with tuneable conductivity,” said Vijayaraghaven.
“When the lipids contain binding sites such as the enzyme called biotin, we show that it actively binds with a protein called streptavidin. Also, when we use charged lipids, there is charge transfer from the lipids into graphene which changes the doping level in graphene. All of these together can be exploited to produce new types of graphene/lipids based bio-sensors.”
L-DPN uses a very sharp tip with an apex of several nanometers as a means to write lipid membranes onto surfaces in a way similar to a quill pen on paper, said Dr Michael Hirtz from KIT.
“The size of the tip and the precision machine controlling it allows of course for much smaller patterns, smaller than cells, and even right down to the nanoscale,” Hirtz said. “By employing arrays of these tips multiple different mixtures of lipids can be written in parallel, allowing for sub-cellular sized patterns with diverse chemical composition.”
Multiplexed biomimetic lipid membranes on graphene by dip-pen nanolithography http://www.nature.com/ncomms/2013/131010/ncomms3591/full/ncomms3591.html
