Anionic/nonionic surfactants for controlled synthesis of highly concentrated sub-50 nm polystyrene spheres

Significant progress in improving Atorvastatin dissolution rate: Physicochemical characterization and stability assessment of self-dispersible Atorvastatin/Tween 80® nanocrystals formulated through wet milling and freeze-drying

Atorvastatin (ATV) is a first-line drug for the treatment of hyperlipidemia. This drug presents biopharmaceutical problems, partly due to its low solubility and dissolution rate. In this work, nanocrystals of ATV stabilized with Tween 80® were designed by wet milling. A full factorial design was applied to optimize the process. Additionally, a cryoprotectant agent (maltodextrin, MTX) was identified, which allowed maintaining the properties of the nanocrystals after lyophilization. The storage stability of the nanocrystals was demonstrated for six months in different conditions. The obtained nanocrystal powder was characterized using SEM, EDXS, TEM, DSC, TGA, FT-IR, and XRD, showing the presence of irregular crystals with semi-amorphous characteristics, likely due to the particle collision process. Based on the reduction in particle size and the decrease in drug crystallinity, a significant increase in water and phosphate buffer (pH 6.8) solubility by 4 and 6 times, respectively, was observed. On the other hand, a noticeable increase in the dissolution rate was observed, with 90 % of the drug dissolved within 60 min of study, compared to 30 % of the drug dissolved within 12 h in the case of the untreated drug or the physical mixture of components. Based on these results, it can be concluded that the nano-milling of Atorvastatin stabilized with Tween 80® is a promising strategy for developing new formulations with improved biopharmaceutical properties of this widely used drug.

Self-supported polypyrrole flexible electrodes for electrochemical reduction of nitrite

The efficiency of an electrochemical oxidation/reduction process strongly depends on the working electrode's surface area to volume ratio. By making electrodes flexible and employing different configurations such as roll-to-roll membrane, the surface area to volume ratio can be enhanced, therefore improving the overall efficiency of electrochemical processes. Conductive polymers emerge as a new framework to enable alternative electrochemical water treatment cell configurations. Self-standing polypyrrole flexible electrodes were synthesized by electropolymerization and evaluated on the treatment of an oxyanion pollutant: nitrite. Mechanical characterization through stress-strain curves and bending tests demonstrated high electrode resilience that sustained over 1000 bending cycles without impacting mechanical integrity or electrocatalytic responses. The electrocatalytic response towards nitrite reduction was assessed under linear scan voltammetry (LSV) and removal performance evaluated under potentiostatic conditions reaching 79% abatement of initial concentrations of nitrite of 15 mg/L [NO2--N]. Self-standing flexible electrodes appear as a novel framework to enable modular compact water treatment unit designs that maximize the electrode area/volume ratio and substitute expensive platinum group metal (PGMs) electrocatalysts.

From Self-Assembly of Colloidal Crystals toward Ordered Porous Layer Interferometry

Interferometry-based, reflectometric, label-free biosensors have made significant progress in the analysis of molecular interactions after years of development. The design of interference substrates is a key research topic for these biosensors, and many studies have focused on porous films prepared by top-down methods such as porous silicon and anodic aluminum oxide. Lately, more research has been conducted on ordered porous layer interferometry (OPLI), which uses ordered porous colloidal crystal films as interference substrates. These films are made using self-assembly techniques, which is the bottom-up approach. They also offer several advantages for biosensing applications, such as budget cost, adjustable porosity, and high structural consistency. This review will briefly explain the fundamental components of self-assembled materials and thoroughly discuss various self-assembly techniques in depth. We will also summarize the latest studies that used the OPLI technique for label-free biosensing applications and divide them into several aspects for further discussion. Then, we will comprehensively evaluate the strengths and weaknesses of self-assembly techniques and discuss possible future research directions. Finally, we will outlook the upcoming challenges and opportunities for label-free biosensing using the OPLI technique.