Search

The mechano‐responsiverelease of small molecules has received extensive attention in ultrasound (US)‐controlled drug release in recent years because it can achieve non‐invasive, spatiotemporally controlled precise drug release. However, the vast majority of small molecules mechano‐release reported so far are based on polymer systems, which suffer from complex preparations and single mechano‐response. Here, an isoguanosine (isoG) visualized mechano‐responsive supramolecular self‐assembly (isoG‐VMRSS) system was successfully constructed by a one‐pot reaction. It is completely composed of small molecules, which allows for multiple mechano‐responsive releases of isoG (at least 9 times) and ultimately has potential for application in US drug release. A combined experimental‐computational approach reveals the supramolecular network structure (formed by the joint action of related metal coordination bonds, boronate ester bonds and hydrogen bonds mediated by isoG) gradually formed inside the system is the underlying internal mechanism. Therefore, it provides a new and effective idea of small molecule release in the field of mechanochemistry. [ABSTRACT FROM AUTHOR]

Elastin‐like polypeptides (ELPs) have been proposed as a simple model of intrinsically disordered proteins (IDPs) which can form membraneless organelles by liquid–liquid phase separation (LLPS) in cells. Herein, the behavior of fluorescently labeled ELP is studied in cytomimetic aqueous two‐phase system (ATPS) encapsulated protocells that are formed using microfluidics, which enabled confinement, changes in temperature, and statistical analysis. The spatial organization of ELP could be observed in the ATPS. Furthermore, changes in temperature triggered the dynamic formation and distribution of ELP‐rich droplets within the ATPS, resulting from changes in conformation. Proteins were encapsulated along with ELP in the synthetic protocells and distinct partitioning properties of these proteins and ELP in the ATPS were observed. Therefore, the ability of ELP to coacervate with temperature can be maintained inside a cell‐mimicking system. [ABSTRACT FROM AUTHOR]

Supramolecular assembly: Spherical and stable hybrid assemblies based on a cationic polymer with spermine side chains and an anionic Gd3+‐containing polyoxometalate cluster (GdW) are prepared by electrostatic interaction (see figure). The T1‐weighted MRI performance of GdW is enhanced about three times in the assemblies; meanwhile, the assemblies show good biocompatibility, which enables them to be promising candidates for MRI contrast agents. [ABSTRACT FROM AUTHOR]

Rheological behaviors of ultrahigh‐molecular‐weight polyethylene (PE)/high‐density PE/SiO2 blends are investigated using parallel‐plate rheometer and capillary rheometer. The molecular chain conformational change mechanism is used to explain flow instabilities during extrusion. The viewpoints are proposed: (1) critical shear rate depends on the relative strength of irreversible viscous loss and reversible elastic orientation for molecular chains in transverse velocity gradient field inside the die and (2) critical shear stress depends on the extent of molecular chain conformational change inside the die, and the ease of conformational recovery after leaving the die. Modified nano‐SiO2 particles are detected a certain interfacial adhesion in PE matrix. The interfacial interaction limits viscous flow inside the die and conformational recovery after leaving the die, thus causing not only the flow instabilities to occur prematurely on shear rate and delaying sharkskin on shear stress, but also an alternate "sharkskin‐melt fracture" appearance after global extrusion fracture. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47713. Schematic diagram of the ternary rheological model of UHMWPE/HDPE/SiO2 [ABSTRACT FROM AUTHOR]