Janus enantiomorphous nanomaterial assembly on substrate surfaces for chirality-dependent cell adhesion

Polymer-mediated self-assembly, dispersion, and phase separation of Janus nanorods

The challenge of stabilizing polymer nanocomposites lies in the fact that nanoparticles tend to phase separate from the polymer melt due to an entropic 'depletion attraction' between nanoparticles. Additionally, composites of polymer and nanorods show a decrease in miscibility with increasing nanorod aspect ratio [U. K. Sankar and M. Tripathy, Macromolecules, 2015, 48, 432-442; U. Erigi, U. Dhumal and M. Tripathy, J. Chem. Phys., 2021, 154, 124903]. In this work, we have studied the structure and phase behaviour of polymer-Janus nanorod mixtures using Polymer Reference Interaction Site Model (PRISM) theory and molecular dynamics simulations. The composite system of polymer and Janus nanorods of two different thicknesses, at various Janus nanorod densities, and for different interaction strengths between polymer and attractive sites of Janus nanorods (ε_pa), is investigated for their miscibility and self-assembly. At low Janus nanorod density, PRISM theory predicts transitions from the entropic depletion-driven contact aggregation of Janus nanorods to a well-dispersed phase to the bridging-driven phase separation of Janus nanorods, with increasing ε_pa. This behaviour is similar to earlier predictions for homogeneous nanorods. However, molecular dynamics simulations do not confirm the bridging-driven phase separation at high ε_pa predicted by PRISM theory. We find that both PRISM theory and molecular dynamics simulations are in agreement in the intermediate and high Janus nanorod density regimes. PRISM theory predicts, and simulations confirm, that at high Janus nanorod densities, the system undergoes a transition from depletion-driven macrophase separation to dispersion to chemical anisotropy-driven self-assembly with increasing ε_pa. The self-assembly at high ε_pa is mediated by the polymer. At intermediate Janus nanorod densities, the usual transition from an entropic depletion-driven macrophase separation to dispersion is predicted at low ε_pa. At high ε_pa, both PRISM theory and molecular dynamics simulations show transition to a state that is simultaneously macrophase separated and microphase separated (self-assembled).

Enantioselective effect of cysteine functionalized mesoporous silica nanoparticles in U87 MG and GM08680 human cells and Staphylococcus aureus bacteria

Chirality is a fundamental phenomenon in biological systems, since most of the biomolecules and biological components and species are chiral and therefore recognize and respond differently depending on the enantiomer present. With increasing research into the use of nanomaterials for biomedical purposes, it is essential to understand the role that chirality of nanoparticles plays at the cellular level. Here, the chiral cysteine functionalization of mesoporous silica nanoparticles has been shown to broadly affect its interaction with U87 MG human glioblastoma cell, healthy human fibroblast (GM08680) and methicillin-resistant S. aureus bacteria. We believe that this research is important to further advancement of nano-biotechnology.

Cell adhesion and proliferation in chiral pores triggered by polyoxometalates

The chirality of polyoxometalate anchoring in the cavity of pitted films was demonstrated to strongly influence the adhesion and proliferation of E. coli cells.

Self-assembled monolayers of chiral periodic mesoporous organosilica as a stimuli responsive local drug delivery system

pH responsive PMOs deliver higher dosages of drugs to malignant cells while delivering less of the drugs to healthy cells.

Biodegradable Anisotropic Microparticles for Stepwise Cell Adhesion and Preparation of Janus Cell Microparticles

The biomimetic anisotropic particles have different physicochemical properties on the opposite two sides, enabling diverse applications in emulsion, photonic display, and diagnosis. However, the traditional anisotropic particles have a very small size, ranging from submicrons to a few microns. The design and fabrication of anisotropic macron-sized particles with new structures and properties is still challenging. In this study, anisotropic polycaprolactone (PCL) microparticles well separated with each other were prepared by crystallization from the dilute PCL solution in a porous 3D gelatin template. They had fuzzy and smooth surfaces on each side, and a size as large as 70 μm. The fuzzy surface of the particle adsorbed significantly larger amount of proteins, and was more cell-attractive regardless of the cell types. The particles showed stronger affinity toward fibroblasts over hepatocytes, which paved a new way for cell isolation merely based on the surface morphology. After a successive seeding process, Janus cell microparticles with fibroblasts and endothelial cells (ECs) on each side were designed and obtained by making use of the anisotropic surface morphology, which showed significant difference in EC functions in terms of prostacyclin (PGl2) secretion, demonstrating the unique and appealing functions of this type of anisotropic microspheres.