Departmental Seminar: 10.01.18
8 January 2018
Controlled Assembly of Carbon Nanotube Nanohybrids: Single-Molecule Investigations and Beyond
Dr Matteo Palma
Department of Chemistry
Queen Mary University of London, UK.
Wednesday 10th January, 3pm, Ramsay Lecture Theatre
We present a universal approach for the generation of multifunctional nanomaterials that employ molecular building blocks assembled on carbon nanotube (CNTs) electrodes. We will demonstrate single-molecule control in the formation of both static and dynamic nanohybrids via the in-solution assembly of classes of molecular materials (organic, inorganic, and biological with promising attributes) to DNA wrapped CNTs. We will first discuss the in-solution linking of metallic single-walled CNTs (SWCNTs) with different conjugated molecular wires. Conductive atomic force microscopy measurements performed at different locations along the junctions (Figure 1a), allowed us to measure the molecular conductance of a series of oligophenyls, highlighting the potential of an all-carbon based approach for solution-processable molecular electronics. Furthermore, we produced organic-inorganic heterostructures consisting of single Quantum Dots (QDs) univocally linked at the terminal ends of individual SWCNTs. Monofunctionalized SWCNT-QD heterostructures were obtained and photophysical investigations at the single nanohybrid level showed evidence of electronic coupling (Figure 1b). Moreover, DNA linkers of differing lengths were used as molecular rulers to control the distance, and hence tune the energy/charge transfer between the two nanostructures. A dynamic SWCNT-QD hybrid was assembled using a G-quadruplex DNA linker; the distance between the SWCNT and QD was then be dynamically modulated by the introduction and removal of potassium ions (K+); the system was further found to be sensitive to K+ concentrations from 1pM to 25mM. Additionally, we will demonstrate the selective electrical addressability of proteins via the use of carbon nanoelectrodes. We investigated different one-to-one CNT-protein configurations and obtained single-molecule evidence of site-specific coupling between SWCNTs and specific proteins of interest (Figure 1c). Finally, we will we present a strategy for the fabrication of reconfigurable and solution processable nanoscale biosensors with multi-sensing capability, based on SWCNTs. The CNTs were functionalised with specific nucleotide sequences that were employed as selective recognition elements for biomarkers indicative of stress and neuro-trauma conditions. Multiplexed detection of three different biomarkers was successfully performed and real-time detection was achieved in serum with concentrations down to 50 nM, 10 nM and 500 pM. By and large, we demonstrate a novel in-solution approach for the assembly of individual molecules on carbon nanotube electrodes with single-molecule control. The assembled heterostructures show promise in the fabrication of solution-processable nanoelectronic devices for applications that range from molecular electronics to sensing.
 J. Zhu, J. McMorrow, R. Crespo-Otero, G. Ao, M. Zheng, W. P. Gillin, M. Palma, J. Am. Chem. Soc., 2016, 138, 2905-2908
 A. Attanzio, A. Sapelkin, F.Gesuele, A. van der Zande, W. P. Gillin, M. Zheng, M. Palma, Small, 2017, 13, 1603042
 M. Freeley, A. Attanzio, A. Cecconello, G. Amoroso, P.Clement, F. Gesuele, M. Palma Submitted
 M. Freeley, H. L. Worthy, R. Ahmed, B. Bowen, J. E. Macdonald, M. Zheng, D.D. Jones, M. Palma, J. Am. Chem. Soc. 2017, 139, 17834
 X. Xu, P. Clement, J. V. R. Eklöf, N. Kelley-Loughnane, K. Moth-Poulsen J. L. Chávez, M. Palma, Submitted