Thermophoresis and the ‘Origin-of-Life’ concept

Niether, Doreen; Wiegand, Simone; Dhont, Jan K.G.; Afanasenkau, Dzmitry

Conference Presentation (Invited)

FZJ-2017-03938

Thermophoresis and the ‘Origin-of-Life’ concept

Niether, D. (Corresponding author)FZJ* ; Afanasenkau, D. ; Dhont, J. K. G.FZJ* ; Wiegand, S.FZJ*

2017

116th General Assembly of the German Bunsen Society for Physical Chemistry, Bunsentagung 2017, Kaiserslautern, Germany, 25 May 2017 - 27 May 2017

Please use a persistent id in citations: http://hdl.handle.net/2128/14688

Abstract: Formamide is of special interest in the 'origin-of-life' concept as it forms a number of prebiotic molecules under catalytic conditions and at sufficiently high concentrations [1]. For nucleotides and short DNA strands, numerical finite-element calculations have shown that a high degree of accumulation in hydrothermal pores occurs [2]. Using thermophoretic data of the formamide/water system measured with Infra-Red Thermal Diffusion Forced Rayleigh Scattering, we show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations high enough to initiate synthesis of prebiotic nucleobases. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behaviour of formamide. Starting with a formamide concentration of 10-3 wt%, estimated to be typical in shallow lakes on early earth [3], the accumulation-fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of approximately 85 wt% at large aspect ratios [4]. Time dependent studies show that these high concentrations are reached after 45-90 days. To understand the dependence of the accumulation on pore geometry, we derived a heuristic model to illuminate the process.[1] Pino, S.; Sponer, J. E.; Costanzo, G.; Saladino, R. and Di Mauro, E.; Life, 5, 372-384, 2015. [2] Baaske, P.; Weinert, F. M.; Duhr, S.; Lemke, K. H.; Russell, M. J. and Braun,D.; Proc. Natl. Acad. Sci. USA, 104, 9346-9351, 2007.[3] Miyakawa, S.; Cleaves, H. J. and Miller, S. L.; Origins Life Evol. Biosphere, 32, 195-208, 2002.[4] Niether, D.; Afanasenkau, D.; Dhont, J.K.G.; Wiegand, S.; Proc. Natl. Acad. Sci. USA, 113, 4272–4277, 2016.

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