Advanced 3D and 4D microstructure study of single granule formation for pharmaceutical powders using synchrotron x-ray imaging

Monitoring the microstructure of the granule in the wet granulation process could play a decisive role in obtaining high-quality granules. Due to the complex, fast and opaque nature of wet granulation, it cannot be captured by conventional methods. In this study, synchrotron x-ray imaging was employed for the first time to investigate the internal real-time pore evolution during the granule formation process, based on the single droplet impact method. It was found that granules from coarser and more homogenous powders experienced a higher rate of pore evolution during nucleation with a more uniform pore distribution. Dynamic wetting studies showed the granule formation mechanisms, the crater mechanism was found for most binary mixtures with 50 wt. % excipients. According to the physical tests, the granules with lower porosity and finer pores exhibited higher hardness and a slower dissolution rate.     

Engineering Route for Stretchable, 3D Microarchitectures of Wide Bandgap Semiconductors for Biomedical Applications

Wide bandgap (WBG) semiconductors have attracted significant research interest for the development of a broad range of flexible electronic applications, including wearable sensors, soft logical circuits, and long-term implanted neuromodulators. Conventionally, these materials are grown on standard silicon substrates, and then transferred onto soft polymers using mechanical stamping processes. This technique can retain the excellent electrical properties of wide bandgap materials after transfer and enables flexibility; however, most devices are constrained by 2D configurations that exhibit limited mechanical stretchability and morphologies compared with 3D biological systems. Herein, a stamping-free micromachining process is presented to realize, for the first time, 3D flexible and stretchable wide bandgap electronics. The approach applies photolithography on both sides of free-standing nanomembranes, which enables the formation of flexible architectures directly on standard silicon wafers to tailor the optical transparency and mechanical properties of the material. Subsequent detachment of the flexible devices from the support substrate and controlled mechanical buckling transforms the 2D precursors of wide band gap semiconductors into complex 3D mesoscale structures. The ability to fabricate wide band gap materials with 3D architectures that offer device-level stretchability combined with their multi-modal sensing capability will greatly facilitate the establishment of advanced 3D bio-electronics interfaces.     

Aggregation and adsorption behavior of cobalt-based metallosurfactant in water–ethylene glycol media forming worm-like micelles

The cobalt based metallosurfactant cis-chlorobis(ethylenediamine)hexadecylaminecobalt(III) chloride (CHCC) has been prepared and well characterized by utilizing elemental analysis, NMR (¹H, ¹³C), FT-IR and UV–Vis spectroscopy. The CHCC metallosurfactant shows thermal stability up to 168°C. The micellization behavior of the synthesized CHCC metallosurfactant has been investigated systematically by the tensiometric, conductometric, and fluorescence techniques. The critical micelle concentration (cmc) values of CHCC have been determined in various water–ethylene glycol mixtures ranging from 0 to 100 weight % of ethylene glycol at 293.15, 298.15, 303.15, and 308.15 K. The physicochemical parameters namely counterion binding constant, surface pressure, surface excess, surface area covered per CHCC metallosurfactant molecule, free energy minimum, standard free energies of micellization and adsorption, standard enthalpy and entropy of micellization, and Gibb's free energy of transfer have been calculated. The hydrodynamic diameters and zeta potentials of the CHCC metallomicelles have been measured by dynamic light scattering method. Transmission electron microscopy was employed to confirm the presence of worm-like micelles.