Thin, sensitive skin electronics: The properties of the human sense of touch, including high sensitivity to differences in temperature, pressure, or surface roughness, are challenging to replicate in robotics because skin materials must be highly conductive, stretchable, and thin. Jung et al . developed a process to assemble nanomaterials as a monolayer that is partially embedded in an ultrathin elastomer. The process works by depositing a mixed solvent containing nanostructured silver and/or gold, along with elastomer, onto deionized water. This results in a layer of nanoparticles residing at the interface coating with elastomer, which is further densified by the addition of surfactant. The process is scalable, and the resulting elastomer membranes can be transferred to other substrates. —MSL

Implantation of biodegradable wafers near the brain surgery site to deliver anti-cancer agents which target residual tumor cells by bypassing the blood-brain barrier has been a promising method for brain tumor treatment. However, further improvement in the prognosis is still necessary. We herein present novel materials and device technologies for drug delivery to brain tumors, i.e., a flexible, sticky, and biodegradable drug-loaded patch integrated with wireless electronics for controlled intracranial drug delivery through mild-thermic actuation. The flexible and bifacially-designed sticky/hydrophobic device allows conformal adhesion on the brain surgery site and provides spatially-controlled and temporarily-extended drug delivery to brain tumors while minimizing unintended drug leakage to the cerebrospinal fluid. Biodegradation of the entire device minimizes potential neurological side-effects. Application of the device to the mouse model confirms tumor volume suppression and improved survival rate. Demonstration in a large animal model (canine model) exhibited its potential for human application.

Hydrogels are widely implemented as key materials in various biomedical applications owing to their soft, flexible, hydrophilic, and quasi-solid nature. Recently, however, new material properties over those of bare hydrogels have been sought for novel applications. Accordingly, hydrogel nanocomposites, i.e., hydrogels converged with nanomaterials, have been proposed for the functional transformation of conventional hydrogels. The incorporation of suitable nanomaterials into the hydrogel matrix allows the hydrogel nanocomposite to exhibit multi-functionality in addition to the biocompatible feature of the original hydrogel. Therefore, various hydrogel composites with nanomaterials, including nanoparticles, nanowires, and nanosheets, have been developed for diverse purposes, such as catalysis, environmental purification, bio-imaging, sensing, and controlled drug delivery. Furthermore, novel technologies for the patterning of such hydrogel nanocomposites into desired shapes have been developed. The combination of such material engineering and processing technologies has enabled the hydrogel nanocomposite to become a key soft component of electronic, electrochemical, and biomedical devices. We herein review the recent research trend in the field of hydrogel nanocomposites, particularly focusing on materials engineering, processing, and device applications. Furthermore, the conclusions are presented with the scope of future research outlook, which also includes the current technical limitations.