Regensburg 2019 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 6: Poster I
BP 6.1: Poster
Montag, 1. April 2019, 17:30–19:30, Poster B2
Nano-stir bars for perturbing biofluid microdroplets in a microfluidic channel — •Mithun Thampi, Pierre-Yves Gires, and Matthias Weiss — Experimental Physics I, University of Bayreuth, Germany
Studying reactions in the cytoplasm of living cells or in biofluid droplets, e.g. produced in microfluidic channels for lab-on-chip applications, is key for elucidating the dynamics of living matter. However, due to their small dimensions, a controlled and gentle stirring of the interior of biofluid droplets, e.g. for speeding up diffusion-limited reactions, has remained challenging. Here we report on an approach to synthesizing few micrometers long magnetic nano-stir bars (NSBs) for perturbing biofluid microdroplets. NSBs were produced by aligning Fe3O4 nanoparticles via magnetic fields and adding a biocompatible silica coating, followed by magnetic sedimentation to extract the required length range from the polydisperse bulk solution. Scanning electron microscopy confirmed the successful production and isolation of NSBs. Incorporating NSBs into aqueous biofluid microdroplets, produced at PDMS-based microfluidic junctions within a hydrophobic carrier fluid, and addressing them with alternating magnetic fields resulted in a rotational motion of NSBs with angular frequencies in the range 0.01-10 Hz. The resulting gentle mixing of the droplets’ interior was monitored via fluorescence microscopy.