Abstract
Early detection and monitoring of plant stress are essential for understanding plant biology and enhancing agricultural productivity. However, previous methods for detecting plant stress typically required labor-intensive and time-consuming sample preparations, limiting their applications for in vivo real-time analyses. Here, we report a microneedle-shaped field-effect transistor (FET) biosensor for the in vivo real-time monitoring of stressinduced response in plants. DNA structures were immobilized on Au@Pt nanoparticles and then hybridized with a microneedle-shaped MXene-FET to construct a sensor platform for the direct in vivo monitoring of plant re sponses to drought stress. This strategy allowed us to detect abscisic acid (ABA), a key phytohormone involved in drought stress response, down to attomolar concentrations and selectively discriminate it from other phyto hormones. As a proof of concept, our microneedle sensor enabled us to rapidly monitor changes in ABA levels in tomato stems and leaves under osmotic stress, demonstrating its capability to detect stress responses prior to significant changes in enzyme gene expression. In this regard, our method promises versatile applications such as studies of plant hormone signaling and agricultural applications.


http://dx.doi.org/10.1016/j.snb.2025.139412