Fumonisin B1 (FB1), a highly carcinogenic mycotoxin prevalent in agricultural products, necessitates rapid and selective detection methods to address the limitations of conventional analytical methods. Here, we present a molecularly imprinted photoelectrochemical (MIP-PEC) sensor that combines oxygen vacancy (OV)-engineered Bi2S3/Bi4O5Br2 heterojunction and molecular imprinting technology for ultrasensitive detection of FB1. Bi4O5Br2 nanoparticles incorporating OVs are synthesized via an alcoholysis method, where alkaline hydrolysis weakens Bi-O bonds to create OVs, enhancing visible-light utilization efficiency and suppressing charge recombination. A self-sacrificial strategy enables in-situ growth of Bi2S3 nanosheets on Bi4O5Br2, forming a tightly coupled heterojunction. This Bi2S3/Bi4O5Br2 composite exhibits a 10.3-fold higher photocurrent than pristine Bi4O5Br2. The electron lifetimes of Bi4O5Br2 and Bi2S3/Bi4O5Br2 are measured to be 0.32 ms and 0.40 ms, respectively. Furthermore, the Bi2S3/Bi4O5Br2 heterojunction significantly increases incident photon conversion efficiency (IPCE) from 9.0% (for Bi4O5Br2) to 93.1%, attributed to the synergistic effects of OVs-induced defect levels and heterojunction-driven carrier separation. Subsequently, a molecularly imprinted polymer (MIP) is grafted onto the composite via UV polymerization. Following the elution of the template molecule (FB1), the MIP provides specific recognition cavities that enable the selective rebinding of FB1, generating concentration-dependent photocurrent suppression. The MIP-PEC sensor achieves a remarkably low detection limit of 0.028 ng/mL and an extensive linear range spanning from 1.0 ng/mL to 1.0 × 105 ng/mL, outperforming existing FB1 detection methods. Practical validation of corn and milk samples demonstrates recovery rates between 95.4% and 108.0%, highlighting the method’s reliability in complex matrices. This work pioneers the integration of defect engineering, heterojunction design, and molecular imprinting, offering a universal platform for monitoring trace levels of contaminants in food safety evaluations and environmental assessments.

Oxygen Vacancy-Engineered Bi₂S₃/Bi₄O₅Br₂ Heterojunction Coupled with Molecular Imprinting for Ultrasensitive Photoelectrochemical Detection of Fumonisin B1 in Food

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发表日期：

2025年11月6日

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Zhoujian Xie,
Chunting Wei,
Jiawen Wu,
Kejing Huang,
Xuecai Tan

摘要

Fumonisin B1 (FB1), a highly carcinogenic mycotoxin prevalent in agricultural products, necessitates rapid and selective detection methods to address the limitations of conventional analytical methods. Here, we present a molecularly imprinted photoelectrochemical (MIP-PEC) sensor that combines oxygen vacancy (OV)-engineered Bi₂S₃/Bi₄O₅Br₂ heterojunction and molecular imprinting technology for ultrasensitive detection of FB1. Bi₄O₅Br₂ nanoparticles incorporating OVs are synthesized via an alcoholysis method, where alkaline hydrolysis weakens Bi-O bonds to create OVs, enhancing visible-light utilization efficiency and suppressing charge recombination. A self-sacrificial strategy enables in-situ growth of Bi₂S₃ nanosheets on Bi₄O₅Br₂, forming a tightly coupled heterojunction. This Bi₂S₃/Bi₄O₅Br₂ composite exhibits a 10.3-fold higher photocurrent than pristine Bi₄O₅Br₂. The electron lifetimes of Bi₄O₅Br₂ and Bi₂S₃/Bi₄O₅Br₂ are measured to be 0.32 ms and 0.40 ms, respectively. Furthermore, the Bi₂S₃/Bi₄O₅Br₂ heterojunction significantly increases incident photon conversion efficiency (IPCE) from 9.0% (for Bi₄O₅Br₂) to 93.1%, attributed to the synergistic effects of OVs-induced defect levels and heterojunction-driven carrier separation. Subsequently, a molecularly imprinted polymer (MIP) is grafted onto the composite via UV polymerization. Following the elution of the template molecule (FB1), the MIP provides specific recognition cavities that enable the selective rebinding of FB1, generating concentration-dependent photocurrent suppression. The MIP-PEC sensor achieves a remarkably low detection limit of 0.028 ng/mL and an extensive linear range spanning from 1.0 ng/mL to 1.0 × 10⁵ ng/mL, outperforming existing FB1 detection methods. Practical validation of corn and milk samples demonstrates recovery rates between 95.4% and 108.0%, highlighting the method’s reliability in complex matrices. This work pioneers the integration of defect engineering, heterojunction design, and molecular imprinting, offering a universal platform for monitoring trace levels of contaminants in food safety evaluations and environmental assessments.

Oxygen Vacancy-Engineered Bi2S3/Bi4O5Br2 Heterojunction Coupled with Molecular Imprinting for Ultrasensitive Photoelectrochemical Detection of Fumonisin B1 in Food

摘要

Oxygen Vacancy-Engineered Bi₂S₃/Bi₄O₅Br₂ Heterojunction Coupled with Molecular Imprinting for Ultrasensitive Photoelectrochemical Detection of Fumonisin B1 in Food