title: Construction of iron-polymer-graphene nanocomposites with low nonspecific adsorption and strong quenching ability for competitive immunofluorescent detection of biomarkers in GM crops.
abstract: We developed a new immunofluorescent biosensor by utilizing a novel nanobody (Nb) and iron-polymer-graphene nanocomposites for sensitive detection of 5-enolpyruvylshikimate-3-phosphate synthase from Agrobacdterium tumefaciens strain CP4 (CP4-EPSPS), which considered as biomarkers of genetically modified (GM) crops. Specifically, we prepared iron doped polyacrylic hydrazide modified reduced graphene nanocomposites (Fe@RGO/PAH) by in-situ polymerization approach and subsequent a one-pot reaction with hydrazine. The resulting Fe@RGO/PAH nanocomposites displayed low nonspecific adsorption to analytes (11% quenching caused by nonspecific adsorption) due to electrostatic, energetic and steric effect of the nanocomposites. After Nb immobilizing, the as-prepared Fe@RGO/PAH/Nbs showed good selectivity and high quenching ability (92% quenching) in the presence of antigen (Ag) and polyethylene glycol (PEG) modified CdTe QDs (Ag/QDs@PEG), which is a nearly 4 fold than that of the unmodified GO in same condition. The high quenching ability of Fe@RGO/PAH/Nbs can be used for detection of CP4-EPSPS based on competitive immunoassay with a linearly proportional concentration range of 5-100ng/mL and a detection limit of 0.34ng/mL. The good stability, reproducibility and specificity of the resulting immunofluorescent biosensor are demonstrated and might open a new window for investigation of fluorescent sensing with numerous multifunctional graphene based materials.
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Kaifei
authors.initials: K
authors.lastname: Yin
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China. Electronic address: liuar@seu.edu.cn.
authors.forename: Anran
authors.initials: A
authors.lastname: Liu
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Shangguan
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Mi
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Yuanjian
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Yuewu
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Yuanjian
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device (CMD), Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Songqin
authors.initials: S
authors.lastname: Liu
mesh_terms: D015415:Biomarkers / Q000737:chemistry*; D015374:Biosensing Techniques; D006108:Graphite / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry; D030821:Plants, Genetically Modified; D011108:Polymers / Q000737:chemistry
chemical_list: D015415:Biomarkers; D011108:Polymers; D006108:Graphite; D007501:Iron
keywords: Biosensors; Fluorescence; Graphene; Immunoassay; Protein