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<p>Growing needs for monitoring kanamycin (KAN) residues in food require ultrasensitive, field-deployable determination platforms. Herein, we present a universal photoelectrochemical (PEC) aptasensing strategy that synergizes ZIF-8/Bi<sub>2</sub>S<sub>3</sub> heterostructure-engineered photoelectrodes with strand displacement–triggered biocatalytic signal amplification. The urchin-like ZIF-8/Bi<sub>2</sub>S<sub>3</sub> heterojunction, synthesized through in situ MOF growth on semiconductor nanoarchitectures, demonstrates exceptional photocurrent generation via facilitated carrier separation achieved by directional electron transfer from Bi<sub>2</sub>S<sub>3</sub> to ZIF-8 and hole scavenging by ascorbic acid. Capitalizing on aptamer-target recognition in homogeneous phase, KAN concentration is transduced into messenger DNA (S2) through displacement dynamics, overcoming steric limitations of conventional solid-phase biosensing. The liberated S2 hybridizes with electrode-immobilized S1 to assemble MnPP-loaded dsDNA, where the mimic enzyme catalyzes H<sub>2</sub>O<sub>2</sub>-driven precipitation of benzo-4-chlorohexadienone (4-CD). This biocatalytic insulation layer induces quantifiable photocurrent attenuation proportional to KAN levels (10–1.0 × 10<sup>6</sup>&#xa0;nmol/L), achieving a 0.1&#xa0;nM detection limit superior to ELISA and HPLC. The platform demonstrates 95.7–105.4% recovery in milk matrices and cross-reactivity below 5.8% against structural analogs, validating its specificity. By integrating MOF-semiconductor interfacial engineering with homogeneous-to-heterogeneous signal translation, this work establishes a paradigm for antibiotic monitoring that bridges laboratory innovation with on-site applicability.</p> Graphical abstract <p></p>

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Strand displacement–triggered biocatalytic precipitation on ZIF-8/Bi2S3 photoelectrode: an aptasensing platform for sub-nanomolar kanamycin determination

  • 期刊论文

  • 发表日期：

    2026年3月3日

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  • Zhoujian Xie,
  • Jiawen Wu,
  • Kejing Huang,
  • Xuecai Tan

摘要

Growing needs for monitoring kanamycin (KAN) residues in food require ultrasensitive, field-deployable determination platforms. Herein, we present a universal photoelectrochemical (PEC) aptasensing strategy that synergizes ZIF-8/Bi2S3 heterostructure-engineered photoelectrodes with strand displacement–triggered biocatalytic signal amplification. The urchin-like ZIF-8/Bi2S3 heterojunction, synthesized through in situ MOF growth on semiconductor nanoarchitectures, demonstrates exceptional photocurrent generation via facilitated carrier separation achieved by directional electron transfer from Bi2S3 to ZIF-8 and hole scavenging by ascorbic acid. Capitalizing on aptamer-target recognition in homogeneous phase, KAN concentration is transduced into messenger DNA (S2) through displacement dynamics, overcoming steric limitations of conventional solid-phase biosensing. The liberated S2 hybridizes with electrode-immobilized S1 to assemble MnPP-loaded dsDNA, where the mimic enzyme catalyzes H2O2-driven precipitation of benzo-4-chlorohexadienone (4-CD). This biocatalytic insulation layer induces quantifiable photocurrent attenuation proportional to KAN levels (10–1.0 × 106 nmol/L), achieving a 0.1 nM detection limit superior to ELISA and HPLC. The platform demonstrates 95.7–105.4% recovery in milk matrices and cross-reactivity below 5.8% against structural analogs, validating its specificity. By integrating MOF-semiconductor interfacial engineering with homogeneous-to-heterogeneous signal translation, this work establishes a paradigm for antibiotic monitoring that bridges laboratory innovation with on-site applicability.

Graphical abstract