Functionalized mesoporous silica particles offer excellent chemical and morphological properties, making them ideal adsorbents or drug carriers. However, their synthesis involves several energy- and resource-intensive steps, resulting in high economic and environmental costs. In this study, we report a strategy for the direct design of mesoporous silica with ordered mesopores densely functionalized by polyacid chains. The aqueous process relies on polyion complex micelles acting as pH-responsive multifunctional agents. They are first associated to direct the mesostructure of silica, and are then dissociated by a change in pH to reveal the material's mesoporosity and yield functional pores. Ordered mesoporous particles with controlled structure and particle size were obtained, showing dense functionalization of up to 2.1 mmol.gSiO2−1 of carboxylic acid functions, which were fully accessible to ionic exchange in aqueous solution. These highly functionalized materials were then evaluated as reversible adsorbents for the removal of a cationic dye (auramine O). The results revealed high dye uptakes, from 130 to 237 mg.gSiO2−1, which were up to 193 % higher than those achieved with non-functional calcined mesoporous silica particles. These uptakes correlated with the mesoporous volume of the materials, with an average density of around one auramine molecule per nm3 of pore. In addition, the materials exhibited excellent dye adsorption/desorption cyclability by pH stimuli in aqueous solutions under mild conditions, with an average desorption efficiency of 96 % in just 30 min. These results therefore represent an attractive strategy for the design of efficient and sustainable adsorbents for water purification.

In this contribution, I will present the theoretical and numerical advances we achieved that allowed us to recently model the interaction and co-assembly of optical and topological solitons in thin layers of cholesteric [1]. More specifically, we found that a delicate balance between the local transfer of momentum between light and matter and the nonlocal orientational elasticity of the liquid-crystal phase yield complex solitonic tractor beam behavior and self-patterning phenomena. I will show how a combination of free energy minimization techniques, beam propagation [2] and ray-tracing [3] simulations can be exploited to calculate the conservative and nonconservative components of the force that light exerts on a topological soliton, and will also provide a perspective on dissipative transport and out-of-equilibrium phenonema in liquid crystals.[1] G. Poy, et al., Nature Photonics, 16, 454 (2022).[2] G. Poy and Slobodan Žumer, Optics Express, 28, 24327 (2020).[3] G. Poy and Slobodan Žumer, Soft Matter, 15, 3659 (2019).

Most of our knowledge about how the body functions comes from studies carried out on humans or medium to large animals. However, more than 90% of animal biomass is made up of animals weighing less than one gram, whose physiology remains largely unknown, as is that of the embryonic and larval forms of large animals. The difficulty in studying major physiological functions in small animals comes from the limitations of our measuring instruments. To gain insight into the cardiovascular physiology of fish embryos we use nanoindentation and spinning-disk confocal microscopy to obtain quantitative measurements of volume and force variations in zebrafish embryos and larvae. Nanoindentation is a technique designed to probe the elastic modulus of soft materials by pressing a spherical glass probe (6 to 200 µm in diameter) into the surface of the material. The device measures the indentation of the sphere and the compressive force exerted via the deflection of a rod of known stiffness. This equipment can reproducibly indent a wide range of materials with moduli ranging from 1 Pa to 10 GPa and measure forces ranging from 20 pN to 2 mN. We used a nanoindenter coupled with microscopy (Fig. 1) to measure the mechanical activity of the heart of a three-day-old zebrafish embryo. Figure 2 shows what we believe to be the mechanocardiogram of the smallest animal (3.5 mm, approximately 1 mg) ever recorded to date. We were also able to measure periodic pressure variations on a superficial capillary with a diameter smaller than that of a red blood cell.