Department of Mechanical Engineering, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA.
Department of Electrical Engineering, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA.
Biosens Bioelectron. 2024 Nov 15;264:116649. doi: 10.1016/j.bios.2024.116649. Epub 2024 Aug 8.
The advent of wearable sensing platforms capable of continuously monitoring physiological parameters indicative of health status have resulted in a paradigm shift for clinical medicine. The accessibility and adaptability of such portable, unobtrusive devices enables proactive, personalized care based on real-time physiological insights. While wearable sensing platforms exhibit powerful capabilities for continuously monitoring physiological parameters, device fabrication often requires specialized facilities and technical expertise, restricting deployment opportunities and innovation potential. The recent emergence of rapid prototyping approaches to sensor fabrication, such as laser-induced graphene (LIG), provides a pathway for circumventing these barriers through low-cost, scalable fabrication. However, inherent limitations in laser processing restrict the spatial resolution of LIG-based flexible electronic devices to the minimum laser spot size. For a CO laser-a commonly reported laser for device production-this corresponds to a feature size of ∼120 μm. Here, we demonstrate a facile, low-cost stencil-masking technique to reduce the minimum resolvable feature size of a LIG-based device from 120 ± 20 μm to 45 ± 3 μm when fabricated by CO laser. Characterization of device performance reveals this stencil-masked LIG (s-LIG) method yields a concomitant improvement in electrical properties, which we hypothesize is the result of changes in macrostructure of the patterned LIG. We showcase the performance of this fabrication method via production of common sensors including temperature and multi-electrode electrochemical sensors. We fabricate fine-line microarray electrodes not typically achievable via native CO laser processing, demonstrating the potential of the expanded design capabilities. Comparing microarray sensors made with and without the stencil to traditional macro LIG electrodes reveals the s-LIG sensors have significantly reduced capacitance for similar electroactive surface areas. Beyond improving sensor performance, the increased resolution enabled by this metal stencil technique expands capabilities for scalable fabrication of high-performance wearable sensors in low-resource settings without reliance on traditional fabrication pathways.
可穿戴感测平台的出现能够持续监测生理参数，这些参数可以指示健康状况，这为临床医学带来了范式转变。这种便携式、不引人注目的设备的可及性和适应性使基于实时生理洞察的主动、个性化护理成为可能。虽然可穿戴感测平台在持续监测生理参数方面具有强大的功能，但设备制造通常需要专门的设施和技术专业知识，限制了部署机会和创新潜力。最近出现的传感器制造快速原型制作方法，如激光诱导石墨烯（LIG），通过低成本、可扩展的制造提供了规避这些障碍的途径。然而，激光处理固有的限制将基于 LIG 的柔性电子设备的空间分辨率限制在最小激光光斑尺寸。对于 CO 激光——一种常用于设备生产的报告激光——这对应于 45 ± 3 μm 的特征尺寸。在这里，我们展示了一种简单、低成本的掩模技术，可将基于 CO 激光制造的 LIG 器件的最小可分辨特征尺寸从 120 ± 20 μm 降低到 45 ± 3 μm。对器件性能的表征表明，这种掩模 LIG（s-LIG）方法可改善电性能，我们假设这是图案化 LIG 的宏观结构变化的结果。我们通过生产包括温度和多电极电化学传感器在内的常见传感器展示了这种制造方法的性能。我们制造了通常无法通过本地 CO 激光处理实现的细线微阵列电极，展示了扩展设计能力的潜力。将使用和不使用掩模制造的微阵列传感器与传统宏观 LIG 电极进行比较，结果表明 s-LIG 传感器的电容明显降低，对于相似的电活性表面积。除了改善传感器性能外，这种金属掩模技术提高的分辨率扩展了在低资源环境中制造高性能可穿戴传感器的能力，而无需依赖传统的制造途径。
