Oct 11, 2012
Plasmonic pore particles integrate sample delivery and sensing
Detection of low-abundance biomolecules in small sample volumes is likely to play a fundamental role in future healthcare systems. A common limiting factor is the transport of analyte to the sensor surface, which can be improved either by use of nanofluidic delivery systems or by directing analyte binding to only nanoscale sensor elements. Presenting their work in the journal Nanotechnology, researchers from Chalmers University of Technology, Gothenburg, Sweden, have developed a nanoplasmonic sensor platform that enables these two concepts to be combined.
The biosensing platform is based on a thin silicon nitride membrane perforated with arrays of nanopores. Each pore contains a single nanoscale sensor element in the form of a banana-shaped plasmonic nanoparticle. Integrating nanosensors into nanochannels ensures that the analyte can be transported efficiently to every sensitive part of the sensor, enhancing both capture efficiency and time response compared with conventional sensor systems.
Thanks to the material contrast between the plasmonic “nanobananas” (gold) and the rest of the surface (silicon nitride), material-specific surface modifications can be used to ensure that the analyte binds only to the nanoscale sensor elements. In this way, the number of biomolecules “lost” by binding to regions that do not result in a sensor signal will be minimized. This is expected to be of particular importance for applications where the total number of biomolecules is limited, but can also help to reduce sensor response times for mass-transport limited reactions.
The fabrication method is based on a series of deposition and milling steps performed at different angles and enables multiple identical sensor devices to be produced simultaneously. Apart from demonstrating a sensitivity that is comparable to more conventional nanoplasmonic sensors, the Chalmers group also shows that the plasmonic properties of the devices can be tuned easily by varying the thickness of the metal used.
Further information can be found in the journal Nanotechnology.
About the author
Francesco Mazzotta is a PhD student in the division of Biological Physics at Chalmers University of Technology, which is headed by Prof. Fredrik Höök. Magnus P Jonsson received his PhD from the same group and is currently a postdoc in Prof. Cees Dekker’s lab in the Bionanoscience department at Delft University of Technology, the Netherlands.