Boston Ivy Disk-Inspired Pressure-Mediated Adhesive Film Patches.

Boston ivy (Parthenocissus tricuspidata) climbs brick walls using its tendril disks, which excrete a sticky substance to perform binding and attachment. While the cellular structures and adhesive substances involved have been identified for decades, their practical applicability as an adhesive has not yet been demonstrated. A Boston ivy disk-inspired adhesive film patch system is reported in which structural and compositional features of the Boston ivy disk are mimicked with a form of thin adhesive film patches. In analogy to the sticky disk of a mature ivy in which porous microchannels are occupied by catechol-containing microgranules on the bound site, 3,4-dihydroxylphenylalanine bolaamphiphile nanoparticle (DOPA-C7 NP)-coated alginate microgels are two-dimensionally positioned into the cylindrical holes that are periodically micropatterned on the flexible stencil film. Finally, it is demonstrated that the pressurization of the patch breaks the microgels filled in the holes, releasing the polysaccharides and leading to crosslinking with DOPA-C7 NPs via ligandation with combined Ca2+ and Fe3+ ions, thus enabling development of a pressure-mediated adhesion technology.

Monodisperse Microshell Structured Gelatin Microparticles for Temporary Chemoembolization.

Embolization is a nonsurgical, minimally invasive procedure that deliberately blocks a blood vessel. Although several embolic particles have been commercialized, their much wider applications have been hampered owing mainly to particle size variation and uncontrollable degradation kinetics. Herein we introduce a microfluidic approach to fabricate highly monodisperse gelatin microparticles (GMPs) with a microshell structure. For this purpose, we fabricate uniform gelatin emulsion precursors using a microfluidic technique and consecutively cross-link them by inbound diffusion of glutaraldehyde from the oil continuous phase to the suspending gelatin precursor droplets. A model micromechanic study, carried out in an artificial blood vessel, demonstrates that the extraordinary degradation kinetics of the GMPs, which stems from the microshell structure, enables controlled rupturing while exhibiting drug release under temporary chemoembolic conditions.

Cellulose nanofiber-multilayered fruit peel-mimetic gelatin hydrogel microcapsules for micropackaging of bioactive ingredients.

We report a facile but robust approach to fabricate fruit peel-mimetic microcapsules (FPMCs) of which shell was structured by layering cellulose nanofibers (CNFs) with an antioxidant and a waxy compound on monodisperse gelatin microparticles using the layer-by-layer deposition. The thickness and moduli of the shell increased commonly depending on the number of CNF layers, indicating that the incorporation of CNFs made the shell layer rigid. We determined that the coating of the outermost FPMC layer with dodecane nanoemulsions softened the shell surface, thus preventing the generation of microcracks, which is essential for minimizing dehydration in the drying process. Furthermore, we also confirmed that the co-deposition of a phenolic compound, gallic acid, which is encapsulated in the polymeric micelles, with the shell layers allowed the FPMCs to exert antioxidant effects against the influx of oxygen from the atmosphere. These results highlight that our FPMC system could pave the way for the development of a micropackaging technology that enables encapsulation and stabilization of bioactive ingredients.

Conductive magnetic-patchy colloidal microparticles for a high performance pressure sensor.

A robust and straightforward approach for fabrication of a new type of colloidal pressure sensor was proposed. For this purpose, we synthesized uniform conductive magnetic-patchy microparticles using a microfluidic technique and then coated them with poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) layers using the layer-by-layer deposition. Finally we showed that the magnetic-patchy conductive microparticles could be positioned on the target sites while precisely detecting pressure changes with excellent sensitivity.