Double-enzyme active MnO₂@BSA mediated lab-on-paper dual-modality aptasensor for di(2-ethylhexyl)phthalate

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Di(2-ethylhexyl)phthalate (DEHP) is an environmental endocrine disruptor with detrimental effects on ecosystems and human health.
• Highly sensitive and on-site detection methods for DEHP are crucial for environmental monitoring and health risk assessment.

Purpose of the Study:

• To engineer a dual-modality photoelectrochemical (PEC)/colorimetric aptasensing platform for rapid and ultrasensitive DEHP detection.
• To develop an all-in-one lab-on-paper analytical device for convenient field-based DEHP analysis.

Main Methods:

• Fabrication of a polypyrrole paper electrode integrated with cascaded ZnIn2S4/TiO2 photosensitive structures for enhanced PEC signals.
• Utilized double-enzyme active MnO2@BSA nanoparticles (NPs) with peroxidase-mimic and oxidase-mimic activities for signal generation and modulation.
• Employed a target recycling mechanism to amplify the PEC signal and a fluidic channel system for dual-mode detection.

Main Results:

• The cascaded sensitization effect significantly enhanced the photocurrent signal.
• MnO2@BSA NPs induced signal quenching via electron transfer obstruction and steric hindrance, with a target recycling mechanism amplifying the PEC signal.
• Achieved an ultrasensitive DEHP detection limit of 27 fM via PEC and rapid visual detection through colorimetric analysis.

Conclusions:

• The developed dual-modality aptasensing platform provides a sensitive and rapid method for DEHP detection.
• The lab-on-paper device offers a promising approach for on-site, field-based monitoring of DEHP in aqueous environments.
• This work presents a novel paradigm for developing portable analytical tools for environmental contaminants.