Experimental setups to produce and to monitor model membranes have been successfully used for decades and brought invaluable insights into many areas of biology. However, they all have limitations that prevent the full in vitro mimicking and monitoring of most biological processes. Here, a suspended physiological bilayer‐forming chip is designed from 3D‐printing techniques. This chip can be simultaneously integrated to a confocal microscope and a path‐clamp amplifier. It is composed of poly(dimethylsiloxane) and consists of a ≈100 µm hole, where the horizontal planar bilayer is formed, connecting two open crossed‐channels, which allows for altering of each lipid monolayer separately. The bilayer, formed by the zipping of two lipid leaflets, is free‐standing, horizontal, stable, fluid, solvent‐free, and flat with the 14 types of physiologically relevant lipids, and the bilayer formation process is highly reproducible. Because of the two channels, asymmetric bilayers can be formed by making the two lipid leaflets of different composition. Furthermore, proteins, such as transmembrane, peripheral, and pore‐forming proteins, can be added to the bilayer in controlled orientation and keep their native mobility and activity. These features allow in vitro recapitulation of membrane process close to physiological conditions.

Microgels specific structural and functional features are attracting high research interest in several appli- cations such as bioactives and drug delivery or functional food ingredients. Whey protein microgels (WPM) are obtained by heat treatment of whey protein isolate (WPI) in order to promote intramolecular cross-linking. In the present work, atomic force microscopy (AFM) was used in contact mode and in liquid to investigate WPM particles topography and mechanical properties at the nanoscale at native pH (6.5) and acid pH (5.5 and 3.0). Prior to AFM, WPM particles were captured on a gold substrate via low energy interactions by means of specific monoclonal antibodies. AFM images clearly showed an increase in the size of WPM particles induced by pH decrease. AFM in force spectroscopy mode was employed to monitor the elasticity of WPMs. The obtained effective Young’s modulus data showed a significant increase in stiffness at pH 5.5 and pH 3.0, over 15-fold compared to native pH. These findings indicate that the mechanical profile of the WPM network varied with the pH decrease. The WPM topographic and nanome- chanical changes induced by acidification were most likely due to substantial changes in the shape and inner structure of WPM particles. Our results suggest that internally cross-linked structures, modified by acidification could display interesting functional properties when used as a food ingredient.

Chronic kidney disease is characterized by a gradual decline in renal function that progresses toward end-stage renal disease.Podocytes are highly specialized glomerular epithelial cells which form with the glomerular basement membrane (GBM) and capillaryendothelium the glomerular filtration barrier. GBM is an extracellular matrix (ECM) that acts as a mechanical support and providesbiophysical signals that control normal podocytes behavior in the process of glomerular filtration. Thus, the ECM stiffness represents anessential characteristic that controls podocyte function. Hydrolyzed Polyacrylamide (PAAm) hydrogels are smart polyelectrolytes materials.Their biophysical properties can be tuned as desired to mimic the in natural ECM. Therefore, these hydrogels are investigated as new ECM-like constructs to engineer a podocyte-like basement membrane that forms with cultured human podocytes a functional glomerular-like filtration barrier. Such ECM-like PAAm hydrogel construct will provide unique opportunity to reveal podocyte cell biological responses in an in vivo-like setting by controlling the physical properties of the PAAm membranes. In this work, Hydrolyzed PAAm scaffolds having different stiffness ranging between 0.6− 44 kPa are prepared. The correlation between the hydrogel structural and mechanical properties and Podocytes morphology, elasticity, cytoskeleton reorganization, and podocin expression is evaluated. Results show that hydrolyzed PAAm hydrogels promote good cell adhesion and growth and are suitable materials for the development of future 3D smart scaffolds. In addition, the hydrogel properties can be easily modulated over a wide physiological range by controlling the cross-linker concentration. Finally, tuning the hydrogel properties is an effective strategy to control the cells function. This work addressed the complexity of podocytes behavior which will further enhance our knowledge to develop a kidney-on-chip model much needed in kidney function studies on both healthy and diseased states.