Effect of Relative Humidity on the Thickness of Assembled Silica Colloidal Crystal Films

In order for the colloidal crystal films to be better applied, the influence of relative humidity on the preparation of silica colloidal crystal (SCC) films was systematically studied to solve the problem of different thicknesses of SCC films prepared by different batches under the conditions with the same temperature, concentration of suspension and diameter of the particles. SCC films with 190 nm particles were prepared by static vertical deposition method under different humidity regulated by saturated salt solutions, and the thickness of the films was obtained by an interferometric method. The results showed that the increase in humidity would reduce the thickness of the prepared films, which was believed to be caused by the decrease in evaporation rate after the wetting film absorbs water vapor. A new formula for calculating film thickness was proposed and verified from a series of experiments. With the control of humidity, high-quality SCC films with controlled thickness can be repeatedly prepared.

Boston Ivy-Inspired Disc-Like Adhesive Microparticles for Drug Delivery

Microparticles with strong adherence are expected as efficient drug delivery vehicles. Herein, we presented an ingenious hydrogel microparticle recapitulating the adhesion mechanism of Boston ivy tendrils adhesive discs (AD) for durable drug delivery. The particles were achieved by replicating a silica colloidal crystal aggregates assembled in a droplet template after rapid solvent extraction. Due to their unique shape, the nanostructure, and the sticky hydrogel component, such novel microparticles exhibited prominent adhesive property to the wet tissue environment. It was demonstrated that the bioinspired microcarriers loading with dexamethasone had a good therapeutic effect for ulcerative colitis due to the strong adhesion ability for prolonging the maintenance of drug availability. These virtues make the biomimetic microparticles potentially ideal for many practical clinical applications, such as drug delivery, bioimaging, and biodiagnostics.

Monitoring of Binding Affinity Between Drugs and Human Serum Albumin Using Reflectometric Interference Spectroscopy with Silica Colloidal Crystal Films

When a drug enters an organism, interactions between the drug and proteins in the organism play a vital role in the storage, transport and metabolism of the drug and also affect its nonspecific toxicity, targeting and pharmacodynamic activity. However, monitoring the interaction process is a great challenge in the research of the absorption, transport and metabolic processes of drugs. In this study, we used reflectometric interference spectroscopy (RIfS) and silica colloidal crystal (SCC) film as a sensing platform to detect the binding affinity between human serum albumin (HSA) and indomethacin. SCC films composed of three silica nanospheres with different diameters were fabricated using the vertical evaporation method. HSA was immobilized covalently on SCC film using a very simple approach, and optical thickness was used as a parameter to evaluate the process of drug absorption and desorption. Finally, the optimal SCC film was selected, and three drugs other than indomethacin (i.e., warfarin, salicylic acid and quinine) were used for the validation of this sensing platform. The results verified that SCC film using RIfS is a simple and real-time sensing platform for detecting the affinity between HSA and drugs, which may be widely used in drug development and clinical testing in the future.

Thermally Stable High-Contrast Iridescent Structural Colours from Silica Colloidal Crystal Doped with Monodisperse Spherical Black Carbon Particles as Maverick

Monodisperse black carbon nanoparticles (average diameter: 272 and 511 nm) are prepared by carbonization of monodisperse spherical π-conjugated polymer particles. Meanwhile, silica nanoparticles of different sizes are prepared by conventional...