Regensburg 2025 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 17: Poster Session II

BP 17.35: Poster

Dienstag, 18. März 2025, 18:00–20:30, P4

Optimizing Microfluidic Synthesis of Polymer Beads for In-Vivo Force Cell Sensing — •Jordan Dieter Groh, Alejandro Jurado Jiménez, and Timo Betz — Drittes Physikalisches Institut, Göttingen, Deutschland

Since the first use of deformable beads inside living tissue as force sensors about ten years ago, the technique has been refined with the introduction of new materials and methods to measure deformation. In many experiments, polyacrylamide beads have been used to assess forces in all kinds of in-vivo and in-vitro systems such as developing embryos, cancer spheroids, or reconstituted muscle tissue. However, using shear-induced emulsions as a fabrication method still shows two main limitations: a broad size distribution and small variations in polymer stiffness. We were able to optimize the production of polyacrylamide beads in two ways. First, by adoption of flow-focusing in a microfluidic setup. This technique is commonly employed in diverse fields, including drug delivery and food industry, for creating emulsions with precise control over droplet sizes. Second, by the use of a UV light-sensitive polymerization initiator that was triggered after the emulsion was created. The UV initiation of polymerization is instrumental in avoiding clogging of the microfluidic chips as polymerization happens only after emulsification. These improvements resulted in large beads with diameters of 93 um, which are still too large for many applications. Current approaches aim to reduce the bead size to around 5 um or even below.

Keywords: Microfluidic; Force cell sensors; Cell mechanics; Polyacrylamide