title: A novel layer-by-layer assembled multi-enzyme/CNT biosensor for discriminative detection between organophosphorus and non-organophosphrus pesticides.
abstract: Organophosphate compounds are heavily used in agriculture and military activities, while non-organophosphate pesticides are mostly used in agriculture and home defense. Discriminative detection of such toxic compounds is very challenging and requires sophisticated and bulky instrumentation. Meanwhile, multi-enzyme biosensors may offer an effective solution to the problem and may become a versatile analytical tool for discriminative detection of different neurotoxins. In this study, we report for the first time a novel bi-enzyme biosensing system incorporating electrostatically interacted enzyme-armored MWCNT-OPH and MWCNT-AChE along with a set of cushioning bilayers consisting of MWCNT-polyethyleneimine and MWCNT-DNA on glassy carbon electrode for discriminative detection of organophosphorus (OP) and non-organophosphorus (non-OP) pesticides. LbL interfaces were characterized by surface plasmon resonance and electrochemical impedance spectroscopy, demonstrating stepwise assembly and electron conductivity studies. The detection limit was found to be ~0.5 for OP pesticide paraoxon and 1 μM for non-OP pesticide carbaryl, in a wide linear range. The biosensor performance was also validated using apple samples. Remarkable discriminative and straightforward detection between OP and non-OP neurotoxins was successfully achieved with cyclic voltammetry (CV) and UV-vis methods on the MWCNT-(PEI/DNA)2/OPH/AChE biosensor, showing great potential in large screening of OP and non-OP pesticides in practical applications.
authors.affiliation: Department of Materials Engineering, Auburn University, Auburn, AL 36832, USA.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Materials Engineering, Auburn University, Auburn, AL 36832, USA.
authors.forename: Mary A
authors.initials: MA
authors.lastname: Arugula
authors.affiliation: Department of Biochemistry & Biophysics, Texas A&M, College Station, TX, USA.
authors.forename: Melinda
authors.initials: M
authors.lastname: Wales
authors.affiliation: Department of Biochemistry & Biophysics, Texas A&M, College Station, TX, USA.
authors.forename: James
authors.initials: J
authors.lastname: Wild
authors.affiliation: Department of Materials Engineering, Auburn University, Auburn, AL 36832, USA. Electronic address: als@auburn.edu.
authors.forename: Aleksandr L
authors.initials: AL
authors.lastname: Simonian
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D043303:Aryldialkylphosphatase / Q000737:chemistry; D015374:Biosensing Techniques; D058266:Dielectric Spectroscopy; D004800:Enzymes, Immobilized / Q000737:chemistry; D006801:Humans; D037742:Nanotubes, Carbon / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000009:adverse effects / Q000302:isolation & purification*; D010261:Paraoxon / Q000737:chemistry; D010575:Pesticides / Q000009:adverse effects / Q000302:isolation & purification*
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D009943:Organophosphorus Compounds; D010575:Pesticides; D000110:Acetylcholinesterase; D043303:Aryldialkylphosphatase; D010261:Paraoxon
keywords: Carbaryl; Discriminative detection; Layer-by-layer self-assembly; Multi-enzyme; Multi-walled carbon nanotube (MWCNT); Paraoxon