Department of Chemistry, Savitribai Phule Pune University, Ganeshkhind Road, Pune, 411007, India.
Department of Chemistry, Savitribai Phule Pune University, Ganeshkhind Road, Pune, 411007, India.
Int J Biol Macromol. 2018 Mar;108:32-40. doi: 10.1016/j.ijbiomac.2017.11.136. Epub 2017 Nov 22.
A potentiometric biosensor based on agarose-guar gum (A-G) entrapped bio-nanoconjugate of urease with gold nanoparticles (AUNps), has been reported for the first time for glyphosate detection. The biosensor is based on inhibition of urease activity by glyphosate, which was measured by direct potentiometry using ammonium ion selective electrode covered with A-G-urease nanoconjugate membrane. TEM and FTIR analysis revealed nanoconjugate formation and its immobilization in A-G matrix respectively. The composite biopolymer employed for immobilization yields thin, transparent, flexible membrane having superior mechanical strength and stability. It retains the maximum activity (92%) of urease with negligible leaching. The conjugation of urease with AUNps allows improvement in response characteristics for potentiometric measurement. The biosensor shows a linear response in the glyphosate concentration range from 0.5ppm-50ppm, with limit of detection at 0.5ppm, which covers maximum residual limit set by WHO for drinking water. The inhibition of catalytic activity of urease nanoconjugate by gyphosate was confirmed by FTIR analysis. The response of fabricated biosensor is selective towards glyphosate as against various other pesticides. The biosensor exhibits good performance in terms of reproducibility and prolonged storage stability of 180days. Thus, the present biosensor provides an alternative method for simple, selective and cost effective detection of glyphosate based on urease inhibition.
一种基于琼脂糖-瓜尔胶（A-G）包埋的脲酶与金纳米粒子（AUNps）生物纳米复合物的电位生物传感器，首次被报道用于检测草甘膦。该生物传感器基于草甘膦对脲酶活性的抑制作用，通过用铵离子选择性电极直接测定，电极表面覆盖有 A-G-脲酶纳米复合物膜。TEM 和 FTIR 分析分别显示了纳米复合物的形成及其在 A-G 基质中的固定化。用于固定化的复合生物聚合物可形成具有优异机械强度和稳定性的薄、透明、柔韧的膜。它保留了脲酶的最大活性（92%），几乎没有浸出。脲酶与 AUNps 的结合允许对电位测量的响应特性进行改进。该生物传感器在草甘膦浓度范围从 0.5ppm-50ppm 内显示出线性响应，检测限为 0.5ppm，这涵盖了世界卫生组织对饮用水规定的最大残留限量。FTIR 分析证实了草甘膦对脲酶纳米复合物催化活性的抑制作用。与各种其他农药相比，所制备的生物传感器对草甘膦的响应具有选择性。该生物传感器在重现性和长达 180 天的延长储存稳定性方面表现出良好的性能。因此，本生物传感器为基于脲酶抑制的简单、选择性和经济高效的草甘膦检测提供了一种替代方法。
