Conventional melanoma therapies suffer from the toxicity and side effects of repeated treatments due to the aggressive and recurrent nature of melanoma cells. Less-invasive topical chemotherapies by utilizing polymeric microneedles have emerged as an alternative, but the sustained, long-lasting release of drug cargos remains challenging. In addition, the size of the microneedles is relatively bulky for the small, curvilinear, and exceptionally sensitive cornea for the treatment of ocular melanoma. Here, we report a design of bioresorbable, miniaturized porous-silicon (p-Si) needles with covalently linked drug cargos at doses comparable to those of conventional polymeric microneedles. The p-Si needles are built on a water-soluble film as a temporary flexible holder that can be intimately interfaced with the irregular surface of living tissues, followed by complete dissolution with saline solution within 1 min. Consequently, the p-Si needles remain embedded inside tissues and then undergo gradual degradation, allowing for sustained release of the drug cargos. Its utility in unobtrusive topical delivery of chemotherapy with minimal side effects is demonstrated in a murine melanoma model.

The study of transparent daytime radiative cooling with no additional energy consumption is a promising area of research. Its applications include solar cells and building and automobile windows that are prone to heating issues. Ubiquitous applications necessitate the development of metamaterials with high mechanical flexibility in a scalable manner while overcoming translucence. In this study, visibly clear and flexible radiative cooling metamaterials have been developed using a newly designed optical modulator filled into randomly distributed silica aerogel microparticles in a silicone elastomer. The optical modulator effectively suppresses visible light scattering, thus enabling higher loading of silica aerogel microparticles while securing visible clarity. The significant suppression of the rise in temperature by the metamaterial is verified using both indoor and outdoor experiments. The visibly clear metamaterials deployed in solar cells and windows can effectively suppress the rise in temperature under solar irradiation, thereby mitigating the performance degradation of solar cells by heating issues and suppressing the rise in temperature of indoor air.

A thin transparent wearable patch with silicon nanoneedles is developed for efficient interface with biological cells and tissues.

We report a facile method for fabricating polymer hierarchical structures, which are the engineered, ratchet-like microscale structures with nanoscale dimples, for the directional movement of droplets. The fabricated polymer hierarchical structures with no surface modifier show hydrophobic, superhydrophobic, or omniphobic characteristics depending on their intrinsic polymer properties. Further treatment with a surface modifier endows the polymer surfaces with superomniphobicity. The fabricated polymer substrates with no surface modifier enable the movement of the water droplet along the designed track at almost no inclination of the substrate.

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