During the last couple of decades considerable research efforts have been directed towards the synthesis and coating iron oxide nanoparticles (IONPs) for biomedical applications. To address the current limitations, recent studies have focused on the design of new generation nanoparticle systems whose internalization and targeting capabilities have been improved through surface modifications. This review covers the most recent challenges and advances in the development of IONPs with enhanced quality, and biocompatibility for various applications in biotechnology and medicine.
Indigo and its derivatives are industrially-important dyes known for centuries. The low solubility of these compounds limits their applications and hinders potential synthetic chemistry using indigo as a building-block. Herein we report attachment of the tert-butoxy carbonyl (tBOC) thermolabile protecting group to indigos, allowing their processing into neat thin films as well as mixed films with a semiconducting polymer. Photoinduced charge transfer is observed to and from these pigments and the polymer.
Volatile substances are in high demand, especially in cosmetic and pharmaceutical applications. To prolong their shelf-life and prevent their degradation if exposed to air, these volatile substances are often encapsulated. Most frequently, matrix materials are composed of high-molecular-weight polymers because some of them can efficiently retain volatiles and meet the safety requirements these applications impose. However, these substances must be processed at high concentrations, resulting in viscous solutions that are difficult to spray or emulsify. To address this shortcoming, we employed a lowmolecular-weight substance, succinic acid, as a matrix material to encapsulate a model volatile, vanillin. To facilitate the encapsulation of low-molecular-weight substances, such as volatiles, we produce these particles through surface acoustic wave (SAW)-based microfluidic spray-drying. This technique forms drops with diameters as small as 1−10 μm that dry within a few hundred ms. Thereby, we can kinetically arrest or even suppress phase separations. We demonstrate that vanillin is most efficiently encapsulated and retained over a prolonged time if succinic acid is formulated from solutions initially containing succinic acid concentrations exceeding 10% of its saturation concentration. If appropriately formulated, these succinic acid based particles retain volatiles longer than the much more commonly employed high-molecular-weight dextrin. These results open up a new avenue to encapsulate volatiles in low-molecular-weight compounds that pack more densely than high-molecular-weight counterparts and therefore can retain volatiles for a prolonged time.
A surface acoustic wave based microfluidic spray-drier is used to spray dry succinic acid, a model low molecular weight matrix substance. We demonstrate that the structure of succinic acid can be tuned with its formation time within drying drops.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.