Zhang Wanqing, Zhang Xianzhe, Dutta Ankan, Lorestani Farnaz, Sayeed Biswas Md Abu, Li Bowen, Abdullah Abu Musa, Cheng Huanyu
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, State College, PA, 16802, USA.
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, State College, PA, 16802, USA; Center for Neural Engineering, The Pennsylvania State University, University Park, State College, PA, 16802, USA.
Biosens Bioelectron. 2025 Nov 15;288:117805. doi: 10.1016/j.bios.2025.117805. Epub 2025 Jul 24.
Monitoring chloride ions (Cl) in sweat is critical for assessing hydration, diagnosing cystic fibrosis (CF), and evaluating other health conditions. Existing wearable sweat chloride sensors either exhibit low sensitivity based on potentiometric sensing or irreversible readings based on colorimetric sensing. To address these challenges, we report the design of a hydrogel-based wearable sweat sensor that allows for monitoring of Cl based on an electrolyte concentration gradient. This reported sensor features a coplanar design with a cation-selective hydrogel (CH), a high-salinity hydrogel (HH), and a sweat chamber. The gradient between the HH and the sweat chamber drives ion diffusion through the CH, generating an open-circuit voltage (VOC) that corresponds to the Cl concentration in the sweat chamber. A stable device performance is achieved by further integrating a superhydrophilic poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) thin film that prevents ion exchange and hydrogel swelling. The resulting sensor exhibits an ultrahigh sensitivity of 1.7 mV/mM and a fast response time of 7.1 s, with excellent linearity and reversibility in the range from 10 to 100 mM. Integrating the sensor with a microfluidic module along with temperature calibration provides continuous and calibrated, accurate measurements during physical activities. The design concepts for real-time sweat Cl detection can also be applied to monitor the other biomarkers for personalized diagnostics and health monitoring.
监测汗液中的氯离子（Cl）对于评估水合作用、诊断囊性纤维化（CF）以及评估其他健康状况至关重要。现有的可穿戴汗液氯离子传感器要么基于电位传感表现出低灵敏度，要么基于比色传感呈现不可逆读数。为应对这些挑战，我们报告了一种基于水凝胶的可穿戴汗液传感器的设计，该传感器能够基于电解质浓度梯度监测Cl。所报道的传感器具有共面设计，包括阳离子选择性水凝胶（CH）、高盐度水凝胶（HH）和汗液腔室。HH与汗液腔室之间的梯度驱动离子通过CH扩散，产生与汗液腔室中Cl浓度相对应的开路电压（VOC）。通过进一步集成防止离子交换和水凝胶膨胀的超亲水聚偏氟乙烯 - 六氟丙烯（PVDF - HFP）薄膜，实现了稳定的器件性能。所得传感器表现出1.7 mV/mM的超高灵敏度和7.1 s的快速响应时间，在10至100 mM范围内具有出色的线性和可逆性。将该传感器与微流体模块集成并进行温度校准，可在体育活动期间提供连续、校准且准确的测量。实时汗液Cl检测的设计概念也可应用于监测其他生物标志物，用于个性化诊断和健康监测。
