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Abstract Femtosecond laser‐induced damage threshold (LIDT) testing is carried out at 515 nm on 4‐mm‐sized metalens arrays that are manufactured by direct nanoimprinting of a TiO₂nanoparticle (NP)‐based ink containing either polymeric or inorganic binders. The all‐inorganic TiO₂metalenses exhibit ≈80% absolute focusing efficiency and demonstrate an LIDT of ≈90 mJ cm⁻²based on a single‐shot determination using Liu's method, while the metalenses with the polymeric binder achieve ≈137 mJ cm⁻²and an efficiency of ≈76%. Despite the higher LIDT of the TiO₂‐polymer composite metalenses in the single‐shot experiment, these lenses exhibit significant damage at fluences as low as ≈8 mJ cm⁻²when subjected to ≈6 × 10⁸ pulses at 60 kHz. On the other hand, the all‐inorganic metalenses remain intact under identical conditions at ≈64 mJ cm⁻². That is, the inorganic binder provides superior long‐term stability relative to the polymeric binder and is a more viable solution for high‐energy applications. Structural damages observed in nanostructures result in a reduced deflection efficiency and increase light scattering at the focal plane of the metalens. The LIDT testing is also performed in the nanosecond regime at 532 and 1064 nm with the all‐inorganic metalenses, yielding thresholds of ≈0.5 and ≈5 J cm⁻², respectively. 

Wearable sweat biosensors offer compelling opportunities for improved personal health monitoring and non-invasive measurements of key biomarkers. Inexpensive device fabrication methods are necessary for scalable manufacturing of portable, disposable, and flexible sweat sensors. Furthermore, real-time sweat assessment must be analyzed to validate measurement reliability at various sweating rates. Here, we demonstrate a “smart bandage” microfluidic platform for cortisol detection and continuous glucose monitoring integrated with a synthetic skin. The low-cost, laser-cut microfluidic device is composed of an adhesive-based microchannel and solution-processed electrochemical sensors fabricated from inkjet-printed graphene and silver solutions. An antibody-derived cortisol sensor achieved a limit of detection of 10 pM and included a low-voltage electrowetting valve, validating the microfluidic sensor design under typical physiological conditions. To understand effects of perspiration rate on sensor performance, a synthetic skin was developed using soft lithography to mimic human sweat pores and sweating rates. The enzymatic glucose sensor exhibited a range of 0.2 to 1.0 mM, a limit of detection of 10 μM, and reproducible response curves at flow rates of 2.0 μL min −1 and higher when integrated with the synthetic skin, validating its relevance for human health monitoring. These results demonstrate the potential of using printed microfluidic sweat sensors as a low-cost, real-time, multi-diagnostic device for human health monitoring.