Rapid and sensitive detecting of growth hormone in saliva by hydrogel-based RF sensor

Continuous monitoring of growth hormones is crucial for the healthy development of children and adolescents. Such tracking is fundamental to understanding their dynamic growth processes and assessing the impact of environmental factors, such as nutrition and exercise. However, conventional blood-based methods present significant limitations for frequent monitoring. Herein, we present a non-invasive hydrogel-based radio frequency (RF) sensor for detecting of growth hormones in saliva. The sensing mechanism relies on antigen-antibody binding within the hydrogel matrix, which induces changes in dielectric properties that are converted into measurable resonant frequency shifts. This approach enables rapid detection within approximately 5 min with high sensitivity, achieving low detection limits (0.34 pg/mL for GH and 0.36 pg/mL for IGF-1). Evaluation using saliva samples demonstrated a strong correlation with standard enzyme-linked immunosorbent assay (ELISA). The sensors were further employed for continuous, multi-point monitoring, capturing salivary GH and IGF-1 dynamics under different conditions, such as high-protein diets, exercise, and drug stimulations. Thus, through the data obtained from dynamic physiological monitoring, this work presents a reliable approach for salivary hormone detection and supports the potential application of non-invasive monitoring strategies in pediatric healthcare, particularly for growth disorder screening and management.