Cell-Size Space Regulates the Behavior of Confined Polymers: From Nano- and Micromaterials Science to Biology

Abstract

Polymer micromaterials in a liquid or gel phase covered with a surfactant membrane are widely used materials in pharmaceuticals, cosmetics, and foods. In particular, cell-sized micromaterials of biopolymer solutions covered with a lipid membrane have been studied as artificial cells to understand cells from a physicochemical perspective. The characteristics and phase transitions of polymers confined to a microscopic space often differ from those in bulk systems. The effect that causes this difference is referred to as the cell-size space effect (CSE), but the specific physicochemical factors remain unclear. This study introduces the analysis of CSE on molecular diffusion, nanostructure transition, and phase separation and presents their main factors, i.e., short-and long-range interactions with the membrane surface and small volume (finite element nature). This serves as a guide for determining the dominant factors of CSE. Furthermore, we also introduce other factors of CSE such as spatial closure and the relationships among space size, the characteristic length of periodicity, the structure size, and many others produced by biomolecular assemblies through the analysis of protein reaction−diffusion systems and biochemical reactions.

Cell-size space effects on phase separation of binary polymer blends

“…Panel ( c ) is drawn with reference to Fig. 1 obtained from Yanagisawa, Watanabe et al ( 2022 ), Copyright 2022, The American Chemical Society …”

Cell-Sized Confinements Alter Molecular Diffusion in Concentrated Polymer Solutions Due to Length-Dependent Wetting of Polymers

“…Recently, we demonstrated that such heterogeneous distributions by polymer length can become particularly prominent for binary polymer solutions confined in cell-sized water-in-oil (W/O) droplets covered with a lipid membrane. , Experiments and simulations have revealed that shorter polymers have a higher membrane wettability, which in turn, enhances the localization of short/long polymers at the surface/center of the droplets. This results in LLPS at concentrations where bulk systems would still be in the fully mixed one-phase regime. , Based on those observations, we hypothesized that even in the one-phase regime, spatial heterogeneity can emerge in single-component solutions of polydisperse polymers confined in small droplets owing to the length-dependent membrane wetting of polymers. , …”

“…Recently, we demonstrated that such heterogeneous distributions by polymer length can become particularly prominent for binary polymer solutions confined in cell-sized water-in-oil (W/O) droplets covered with a lipid membrane. 13 , 14 Experiments and simulations have revealed that shorter polymers have a higher membrane wettability, which in turn, enhances the localization of short/long polymers at the surface/center of the droplets. This results in LLPS at concentrations where bulk systems would still be in the fully mixed one-phase regime.…”

Emerging biomaterials for tumor immunotherapy

“…There are various metal oxide nanomaterials with differing properties, which explains their wide application in various fields [ 132 ]. Their extremely small size contributes to their special physical and chemical properties (quantum effect, small size effect, and interface effect) [ 133 ]. Manganese dioxide (MnO 2 ) nanomaterial: Manganese is an essential trace element of the human body.…”