Electrical and fluorescent sensing-based dual-functional detection strategy for ultrasensitive antibiotics analysis

Abstract

Kanamycin (KAN), a typical aminoglycoside antibiotic, has been frequently found in the environment, which causes threats to human health and ecosystems. Ultrasensitive and reliable antibiotic detection strategies are urgently needed. In this study, we propose a dual-functional MXene-based sensing strategy for antibiotic analysis. The sensing platform is fabricated by extended-gate field-effect transistor (EG-FET) with a commercial MOSFET and an extended gate as the sensing electrode. Through electrostatic interaction, Ti₃C₂T_x MXene nanosheets are assembled on ITO glass gate and double-stranded DNA (dsDNA) is modified on MXene surface. The dsDNA is composed of ssDNA and its complementary strand (cs-DNA). In particular, the ssDNA is the specific recognition element for KAN. KAN can compete with csDNA and disrupt the base pairing of dsDNA, causing the release of csDNA. Relying on the EG-FET sensing structure, a fluorescence detection strategy is also developed based on the quenching process of fluorophore (6-Carboxyfluorescein, 6-FAM) labeled cs-DNA (6-FAM-csDNA) on Ti₃C₂T_x MXene, in which the fluorescence intensity of 6-FAM is used as the signal for detecting KAN. This dual-functional MXene-based sensor offers both current response and fluorescence response signals in KAN detection. The reported sensor achieves an ultrasensitive detection performance for KAN with a detection limit of 6.44 fM. The sensor's ability to detect KAN in real water samples further demonstrates its practical application potential in complex environment. This work provides a novel dual-functional strategy for sensitive and highly specific detection of antibiotics, addressing some of the key obstacles in antibiotics detection in various applications.