For developing electrochemical plant sensors, in-situ detection of hormone levels in living plants is worth attempting. A microneedle array sensor based on Au@SnO₂-vertical graphene (VG)/Ta microelectrodes was constructed for analyzing abscisic acid (ABA) in plants. Graphene was vertically grown on Ta wires with a diameter of 0.6 mm by direct current arc plasma jet chemical vapor deposition with SnO₂ as the Au catalyst carrier. These VG nanosheets were embedded with core-shell Au@SnO₂ nanoparticles, and the formation mechanism of the sensing layer was investigated. Three Au@SnO₂-VG microelectrodes, one Ti wire, and one Pt wire were packed into a microneedle array sensor with a three-electrode system. ABA was then quantitatively detected by direct electrocatalytic oxidation, which involves the synergistic catalytic effects of the abundant catalytic active sites of the Au@SnO₂ nanoparticles and the excellent conductivity of the VG nanosheets. The microneedle array sensor responds to ABA in the pH range 4–7, the response concentration range was 0.012 (or 0.024)–495.2 μM, and the detection limit varied between 0.002 and 0.005 μM. The small size, wide pH range, low detection limit, and wide linear concentration range allow the microneedle array sensor to be inserted into plants for in-situ detection of ABA.

为了开发电化学植物传感器，活植物中激素水平的原位检测值得尝试。构建了基于Au@SnO _{2 -}垂直石墨烯（VG）/Ta微电极的微针阵列传感器，用于分析植物中的脱落酸（ABA）。以SnO ₂作为Au催化剂载体，通过直流电弧等离子体喷射化学气相沉积在直径为0.6 mm的Ta线上垂直生长石墨烯。这些VG纳米片嵌入核壳Au@SnO ₂纳米颗粒，并研究了传感层的形成机制。三金@SnO ₂-VG 微电极、一根 Ti 线和一根 Pt 线被装入具有三电极系统的微针阵列传感器中。然后通过直接电催化氧化定量检测 ABA，这涉及 Au@SnO ₂纳米颗粒丰富的催化活性位点和 VG 纳米片优异导电性的协同催化作用。微针阵列传感器在 pH 4-7 范围内响应 ABA，响应浓度范围为 0.012（或 0.024）-495.2 μM，检测限在 0.002 和 0.005 μM 之间变化。小尺寸、宽pH范围、低检测限和宽线性浓度范围允许将微针阵列传感器插入植物中进行ABA的原位检测。