Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 9: Postersession I

BP 9.18: Poster

Montag, 12. März 2018, 17:30–19:30, Poster A

Label-free detection and trapping of individual nanosystems — •Larissa Kohler — KIT, Karlsruhe, Deutschland

The label-free detection of nanosystems provides the opportunity to understand biomolecular dynamics and interactions without undesired modifications of the system. To achieve the high sensitivity required for studying individual nanosystems, we use signal enhancement in a fiber-based Fabry-Perot cavity with high finesse (F ≈ 10⁵), which is integrated in a microfluidic channel. Dispersive interaction between the sample and the cavity field is used to detect the presence and the dynamics of individual nanoobjects. The tight focus of the cavity mode (w₀ ≈ 1 um) can be furthermore harnessed to trap individual particles between the fibers far away from surfaces. At the same time, a polarizable particle shifts the resonance frequency and thereby the intracavity laser power, such that particle motion couples back to the trapping potential. In this so-called self-induced back-action regime, trapping of sub-100 nm is predicted to become possible at biocompatible low intensity levels. We show first results on the detection of 150 nm silica nanoparticles and report the current status of the experiment.