Bifunctional Cu(II)-containing PDA-PEI copolymer dots: Demonstration of a dual-mode platform for colorimetric-fluorescent detection of glyphosate in the environment

• Published in: Talanta (Oxford) 2023-12, Vol.265, p.124865-124865, Article 124865
• Main Authors: Li, Qing, Guo, Yu-Meng, He, Xiang-Yi, Li, Guang-Li
• Format: Article
• Language: English
• Subjects: Colorimetric analysis; Colorimetry; composite polymers; detection limit; Dual-mode; electron transfer; fluorescence; Fluorescence senor; Fluorescent Dyes - chemistry; Glyphosate; marriage; nanomaterials; Peroxidase; Peroxidases; Polydopamine-polyethyleneimine copolymer dots; Polyethyleneimine - chemistry
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2023.124865

The reliable and accurate detection of glyphosate is urgently demanded because it is related to food and environmental safety. In this contribution, a PDA-PEI/Cu2+ complex that possesses peroxidase-mimetic activity and stimulus-responsive fluorescence was fabricated by coordinating Cu2+ with polydopamine-polyethyleneimine copolymer dots (PDA-PEI CPDs). With the introduction of Cu2+, the fluorescence intensity of PDA-PEI CPDs dropped sharply owing to the electron transfer effect. As a peroxidase-mimicking nanozyme, the PDA-PEI/Cu2+ complex owns catalytic capacity to oxidize the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue oxTMB, leading a further fluorescence quenching by internal filtering effect by oxTMB. Once the glyphosate participated, the fluorescence signal of PDA-PEI CPDs is recovered significantly because of the formation of more stable Glyp-Cu2+ complexes, meanwhile the peroxidase-mimicking activity of PDA-PEI/Cu2+ complex could be strongly hindered. According to this principle, a novel and extremely convenient ‘turn off’ colorimetric and ‘turn on’ fluorescence sensing platform can be established for dual-mode detection of glyphosate. The favorable sensitivity and selectivity and were verified in the analysis of glyphosate in the environment through the marriage of dual-signal sensing platform. The detection limit of the dual-mode glyphosate sensing platform was 103.82 ng/mL for colorimetric assay and 16.87 ng/mL for fluorescent assay, respectively. Satisfactory recoveries in the range of 96.40%–104.66% were obtained, indicating the potential of this method for application in complicated real sample. Thereby, this strategy broadens the applications of polydopamine nanomaterials and holds a promising application in determination of pesticide residues. A dual-mode colorimetric-fluorescent sensing platform based on bifunctional Cu(II)-containing polydopamine-polyethyleneimine copolymer dots (PDA-PEI CPDs) for detection of glyphosate in the environment has been reported. This dual-mode strategy enables high sensitivity and selectivity for quantitative analysis of glyphosate. The reliable and accuracy detection of glyphosate in the real samples has also been proved. Taking the advantages of the specific bifunction feature of bifunctional Cu(II)-containing polydopamine-polyethyleneimine copolymer dots, it is anticipated that such a novel strategy based on dual-mode sensing platform with stimulus-responsive fluorescence and peroxidase-mimetic