The focus of our research lies in the synthesis of functional nanoscale materials and studies of their chemical and physical properties. Specifically this focuses on DNA-based systems where nucleobases are modified to develop materials with additional functionality.
DNA has been used as a scaffold for the synthesis of redox-modified DNA using ferrocenyl-nucleosides and the on-chip synthesis of mono- and multi-functionalised strands.
Currently DNA is being investigated as a 1-D nanoguide to self-assemble monomer units of conducting polymers with a particular view towards electronic applications.
We also have projects that investigate the integration of graphene oxide (GO) with biomolecules for sensing applications. We have developed a ink-jet printing protocol for hydrophilic inks that is compatible with standard print conditions drastically simplifying the print process.
Recent Research Highlights
Enzymatic Method for the Synthesis of Long DNA Sequences with Multiple Repeat Units
A polymerase chain reaction (PCR) derived method for preparing long DNA, consisting of multiple repeat units of one to ten base pairs, is described. Two seeding oligodeoxynucleotides, so-called oligoseeds, which encode the repeat unit and produce a duplex with 5′-overhangs, are extended using a thermostable archaeal DNA polymerase. Multiple rounds of heat–cool extension cycles, akin to PCR, rapidly elongate the oligoseed. Twenty cycles produced long DNA with uniformly repeating sequences to over 20 kilobases (kb) in length. The polynucleotides prepared include [A]n/[T]n, [AG]n/[TC]n, [A2G]n/[T2C]n, [A3G]n/[T3C]n, [A4G]n/[T4C]n, [A9G]n/[T9C]n, [GATC]n/[CTAG]n, and [ACTGATCAGC]n/[TGACTAGTCG]n, indicating that the method is extremely flexible with regard to the repeat length and base sequence of the initial oligoseeds. DNA of this length (20 kb≈7 μm) with strictly defined base reiterations should find use in nanomaterial applications.
You can read more about this work here: Whitfield CJ, Turley AT, Tuite EM, Connolly BA, Pike AR. Enzymatic Method for the Synthesis of Long DNA Sequences with Multiple Repeat Units. Angewandte Chemie International Edition 2015, 54(31), 8971-8974.
Ferrocene modified silicon showing ambipolar FET behaviour
As revealed for the first time by in situ scanning tunnelling spectroscopy (STS), ferrocene-modified Si(111) substrates show ambipolar field effect transistor (FET) behaviour upon electrolyte gating. This work was performed in collaboration with Prof. Thomas Wandlowski (University of Bern) and demonstrates the potential for developing molecular based memory systems from ferrocene modified silicon surfaces. In other words, applying a sufficiently positive potential to the silicon substrate transformsferrocene to ferrocenium, which is equivalent to the change of a bit of information from the ‘‘0’’ to the ‘‘1’’ state.This redox process is reversible, and as a consequence one mayerase the stored charge and return the device to its initial state.
We successfully demonstrated the doping of asilicon surface with electrochemically active ferrocene moietiescovalently attached to n-Si(111). The in situ STS study demonstrated unexpected ambipolar FET behaviour of the Si-ferrocene hybrid sample. Control experiments with electrochemicallyinert octene samples show convincingly that allenhancement effects observed in the tunnelling current response are directly related to the presence of the redoxactiveferrocene unit.<.
You can read more about this work here: Artem Mishchenko, Mufida Abdualla, Alexander Rudnev, Yongchun Fu, Andrew R. Pike and Thomas Wandlowski Chem. Commun., 2011, 47, 9807-9809