Agradecimentos: The authors would like to thank Mr. L. Bonugli for his significant contributions to the AFM measurements, Mr. J. R. Castro for technical assistance and the Institute of Physics Gleb Wataghin for the experimental assays support. Also, the authors acknowledge FAPESP (Proc. 2007/05089-9; Proc. 2013/09746-5; Proc. 2009/09120-3), CAPES, CNPq, FAPEMIG (CEX - APQ-02176-11) and nBioNet for their financial support Ver menos

Abstract: Highly sensitive and selective functional nanobio-breaksensors are being developed because they have significant applications in the sustenance and conservation of natural resources and can be used in projects to identify degraded and contaminated areas (of both soil and water) and as environmental quality indicators. In the present study, a nanobiosensor was developed based on using theoretical models (molecular docking and molecular dynamics simulations) based on biomimicry of the action mechanism of herbicides in plants coupled with atomic force microscopy (AFM) tools. The herbicide molecules were detected at very low concentrations using a unique sensor construction: the AFM probes and the substrate were chemically functionalized to favor covalent bonding and promote molecular flexibility, as well as to achieve reproducible and accurate results. Computational methods were used to determine the binding energies associated with the enzyme-herbicide interactions, which were compared with experimental results for adhesion forces. The theoretical results showed that the diclofop herbicide could be assembled and attached onto the mica substrate surface and the ACCase enzyme on the AFM probe without damaging the diclofop molecule. The experimental results showed that using a specific agrochemical target molecule was more efficient than using other nonspecific agrochemicals. On average, there was a 90% difference between the values of specific recognition (diclofop) and nonspecific recognition (imazaquin, metsulfuron, and glyphosate). This result validated the selectivity and specificity of the nanobiosensor. The first evidence of diclofop detection by the AFM probe sensors has been presented in this paper Ver menos