Berlin 2018 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: Biomaterials and Biopolymers (joint session BP/CPP)

CPP 7.11: Talk

Monday, March 12, 2018, 12:30–12:45, H 1058

Light-driven biomolecule electrophoresis by asymmetric photochemistry — •Michael Kieß, Friederike Möller, and Dieter Braun — LMU Munich, Amalienstrasse 54, 80799 München, Germany

Ion and pH gradients across membranes are widespread in biology and are decisive for cell metabolism and signal transmission. We recreate such gradients in bulk water by local photolysis of photodissociable compounds. Focused light creates a non-equilibrium between photoproducts of different charges. Similar to pattern formation in biology, the differential diffusion of the photoproducts generates a radial electric field on a micrometer scale. Charged biomolecules move in this field through electrophoresis, which reaches a steady state within seconds in proportion to exp(-µ/D Φ). The complete description and theoretical analysis of this phenomenon allows us to analyse and manipulate molecules in water. We call this effect photochemical microscale electrophoresis (PME) and use it as a fast, purely optical tool for the simultaneous determination of electrophoretic mobilities, diffusion coefficients and charges of biomolecules (Q∝µ/D) such as DNA and proteins as well as the quantification of binding probabilities. We expect that the presented photochemically induced, electrokinetic reaction-diffusion-migration system will be a versatile playground for further research. It can be a valuable tool for the investigation of electrokinetic effects and for the development of optical methods such as zeta potential measurements or isoelectric focusing. Furthermore, it is likely that the optically controlled interaction of electrical fields with pH and ion gradients may lead to a novel testbed for intracellular processes.