Development and Performance Evaluation of a Hydrogel Microneedle Sensor for In Situ Monitoring of Potassium Ions in Rice Plants

Abstract

Abstract The dynamic balance of potassium ions (K + ) in rice plants is critical to their growth, development, and stress resistance. To achieve in-situ, real-time monitoring of K + levels in rice plants and overcome the limitations of traditional destructive sampling methods, this study developed a biosensor based on ion-selective hydrogel microneedles. Key performance parameters of the sensor, including its calibration curve and sensitivity, were systematically evaluated via in vitro electrochemical tests. Meanwhile, the mechanical strength and microstructure of the microneedles were characterized using micro-force testing. The practical applicability of the sensor was validated through agarose gel recovery experiments and in vivo K + monitoring in rice plants under salt stress, with results cross-validated against ion chromatography as a reference method. The sensor exhibited a sensitivity close to the Nernstian response (59.0 ± 0.11 mV/decade), a linear detection range of 10 − 4 to 10 − 1 M, and a detection limit of 3.0×10 − 5 M. It also demonstrated a fast response time (T 95 + loss in rice leaves under salt stress, showing a strong correlation with the standard method (R 2 = 0.985). In conclusion, the developed hydrogel microneedle sensor is a stable, reliable, and effective tool for in-situ K + analysis in rice plants, providing valuable insights into plant ion physiology and the mechanisms underlying responses to environmental stress.

Plant phenotyping relevance

イネ体内のK⁺を非破壊・リアルタイム測定するセンサーの開発と性能検証が研究の中心であり、植物の生理状態を定量化するフェノタイピング手法に該当する。

Code and data availability

The paper reports a hydrogel microneedle K+ sensor for rice plants, but no public phenotype dataset, image/sensor data deposit, or author analysis code is identified. The only availability statement is 'The data available within the article or its supplementary materials,' with no public URL or repository identifier; a

No evidence-backed public reproduction asset is currently recorded.