Marie Curie Research Training Network Studies on cellular response to targeted single ions using nanotechnology CELLION Dr. Mary Farrell Department of Engineering Sciences The Ångström Laboratory Uppsala, Sweden

Electroanalysis in the Nanodomain : Quinone Monolayers and Sept. 1999-April 2003 Electroanalysis in the Nanodomain : Quinone Monolayers and Nanometer Dimensioned Electrodes Reduction Oxidation (A) Quartz Capillary Platinum Wire (B)

July 2003 – June 2004 INTERCALNET The development of lithium intercalation materials and techniques for their characterisation - + ITO ITO Conduttore ionico Film elettrocromico Materiale a intercalazione

Studies on cellular response to targeted single ions using nanotechnology AIM : To fabricate a nanoelectrode array sensor using ion track technology for the detection of oxygen / nitric oxides Materials used : Polyimide foils – 75 mm Espandex – 50mm Processes / Techniques Wet / Dry etching Lithography Electroplating SEM Electrochemical characterisation

Oxygen Sensing Clark type oxygen electrode Clark, L.C., Trans Am Soc Artif Intern Organs, 1956, 2, 41 Reduction of O2 @ potential 400 – 1200 mV 2e- + ½ O2 + H2O 2 OH- Current proportional to gas concentration Application areas : biosensor development, clinical diagnostics, fermentation control, water and gas analysis and industrial aplications. Much research effort is devoted to the miniturisation of the traditional Clark type cell for many biological and biochemical applications.

Process Steps – Polyimide Irradiation of Polyimide - 75mm Ion track density : 1x106 - 1x107/cm2 PI 75mm Mask 25mm High energy 129Xe27+ One sided Lithography Cu ~ 200 nm Resist Positive Resist : S1813 Spin speed : 1000 rpm, 8sec; 3000 rpm, 40 sec Softbake : Hotplate - 115 deg C, 3 mins Exposure : 17sec – Carl Suss mask aligner MA6/BA6 Development : 40 sec in 1% NaOH solution Hardbake : 115 deg C, 20 mins Dry etch PI (~ 10mm) in aperatures Wet etch pores Sodium hypochloridte (NaOCl), Boric Acid (H3BO3) Etch temperature : 60 deg C Preheating time of solution : 1hour Etch time : varies depending on pH

Process Steps – Polyimide Evaporate Cu on frontside, electroplate Ni Create backside electrode (Ni or Cu) Etch frontside Cu Nanode Sensing side Cu Etching : 320g sodium persulfate Na2(SO4)2 per litre of water Ni electroplating : NiSO4 x 6H2O - 0.41 M Boric Acid (H3BO3) – 0.65 M Applied potential : -0.95 V vs Ag/AgCl, Platinum counter Deposition Time : varied Characterise Ni nanode sensing side in SEM Electrochemical characterisation of Ni nanodes Samples sputtered with gold before SEM analysis EC Characterisation : 0.1 M NaOH Cyclic voltammetry: Potential limits -0.5 to +0.7 V vs Ag/AgCl, platinum counter

Electrochemical Characterisation of Nickel Giovanelli, D., Lawrence, N.S., Li Jiang, Jones, T.G.J., Compton, R.G., Sensors and Actuators B, 2003, 88, 320

Pore Etching Study - Polyimide Etch Time / s Solution pH Pore Diameter / nm 50 9.84 195.72 60 9.82 273.98 75 9.77 322.05 90 9.75 402.54 105 9.73 429.19 120 9.71 485.77 120 minutes etching

Espandex Irradiation of Espandex Cu-PI-Cu : 5-50-5mm Ion track density : 1x106 - 1x107/cm2 Cu ~ 5mm Nanode Sensing side

SEM Characterisation - Espandex

Future Work Acknowledgements Continue work with Polyimide Use single ion tracks to make nanoelectrodes instead of arrays Electrodeposit Au / Pt in pores Characterise using SEM/Olympus microscope, XPS..... Work on the cell for EC measurements - oxygen detection Acknowledgements Prof. Klas Hjort Members of the group : Mikael Lindeberg Hanna Yousef Marek Skupinski Gunjana Sharma Marcus Lehto Roger Boden

Thank you for your attention! Questions / Comments?