Oct 26, 2012
Bio-functionalization fine tunes nanopores for sensing duties
Nanopore-based devices, both biological and synthetic, allow operators to detect and interrogate single molecules that pass through these tiny openings by monitoring the modulation of the pore electrical conductance. This simple transduction mechanism is particularly powerful because it requires only a small sample volume and concentration, greatly decreases the time and cost of analysis, avoids labeling and can mimic basic biological functionalities.
Such devices have already been used successfully to count, sort and manipulate different kinds of molecules and bio-polymers; to study protein folding and unfolding; and to investigate biomolecular interactions. The technique has also been proposed for ultra-rapid DNA sequencing and gene expression profiling.
Most of the present efforts aim to develop smart nanopore based sensors that offer proper selectivity and specific chemical and biological functionalities.
Researchers based at the NANOMED labs in Genova, Italy, have recently demonstrated that by attaching DNA probe molecules to the surface of a solid state nanopore, it is possible to simultaneously resize the opening and make it selective with respect to a specific target. Now, the team has introduced a simple procedure to control this functionalization process, which allows operators to fine tune the pore characteristics.
The proposed approach uses an initial vapour-phase silanization with a variable duration to regulate the final functionalization efficiency, and to tune the thickness of the organic coating, which controls the resizing of the nanostructure. Although quite simple, the preparation method is very powerful and versatile as it is applicable to many different probe molecules.
As shown in the study, to apply the method efficiently requires careful consideration of the parameters influencing the process of chemical modification of nano-confined regions – a fundamental issue for many advanced biotechnological applications.
Further information can be found in the journal Nanotechnology.
About the author
The study was conducted by researchers from NANOMED Labs in the Physics Department of the University of Genova (Italy), directed by Professor U Valbusa. The labs are a partner in the National Collaborative Project NANOMAX: the Italian Flagship Initiative on Biosensing, which provided the financial support. Valentina Mussi is Assistant Professor and coordinates the research activity on nanopore biosensing; Paola Fanzio is a staff researcher involved in the design and development of nanopore and nanochannel devices for single molecule detection; Luca Repetto is Assistant Professor in the Physics Department; with Giuseppe Firpo, a staff technician with expertise in vacuum technology and surface nanostructuring, they realized FIB fabrication and SEM/STEM imaging.