Mazenq, L. | bioRxiv Science

bioRxiv2023

Parallel on-chip micropipettes enabling quantitative multiplexed characterization of vesicle mechanics and cell aggregates rheology

Micropipette aspiration (MPA) is one of the gold standards to quantify biological samples mechanical properties, which are crucial from the cell membrane scale to the multicellular tissue. However, relying on the manipulation of individual home-made glass pipettes, MPA suffers from low throughput and difficult automation. Here, we introduce the sliding insert micropipette aspiration (SIMPA) method, that permits parallelization and automation, thanks to the insertion of tubular pipettes, obtained by photolithography, within microfluidic channels. We show its application both at the lipid bilayer level, by probing vesicles to measure membrane bending and stretching moduli, and at the tissue level by quantifying the viscoelasticity of 3D cell aggregates. This approach opens the way to high-throughput, quantitative mechanical testing of many types of biological samples, from vesicles and individual cells to cell aggregates and explants, under dynamic physico-chemical stimuli.

biophysics↗

bioRxiv2023

An easy-to-use microfluidic mechano-chemostat for tissues and organisms reveals that confined growth is accompanied with increased macromolecular crowding

Conventional culture conditions are oftentimes insufficient to study tissues, organisms, or 3D multicellular assemblies. They lack both dynamic chemical and mechanical control over the microenvironment. While specific microfluidic devices have been developed to address chemical control, they are often hard to use and do not allow the control of compressive forces. Here, we present a set of microfluidic devices which all rely on the use of sliding elements consisting of microfabricated rods that can be inserted inside a microfluidic device. Sliding elements enable the creation of reconfigurable sealed culture chambers for the study of whole organisms or model micro-tissues. By confining the micro-tissues, we studied the biophysical impact of growth-induced pressure and showed that this mechanical stress is associated with an increase in macromolecular crowding, shedding light on this understudied type of mechanical stress. Our mechano-chemostat is an easy-to-use microfluidic device that allows the long-term culture of biological samples and can be used to study both the impact of specific conditions as well as the consequences of mechanical compression.

biophysics↗