Synergistic InSe quantum dots–mesoporous Ta ₂ O ₅ nanostructure for ultrasensitive electrochemical detection of antibiotics in environmental samples

Antibiotic contamination in water resources threatens ecosystems and public health, demanding sensitive and practical monitoring methods. We present an electrochemical sensor based on indium selenide (InSe) quantum dots integrated with mesoporous tantalum pentoxide (Ta₂O₅), forming a synergistic nanostructure with high electrocatalytic activity. The platform enables ultrasensitive detection of antibiotics such as tetracycline, ciprofloxacin, and amoxicillin, achieving a detection limit of ∼2.5 × 10^-11 M. The large surface area of Ta₂O₅ facilitates analyte diffusion, while InSe QDs enhance charge transfer, together ensuring excellent sensitivity, selectivity, and reproducibility (RSD <2%). The sensor retains stability over 30 days and demonstrates recovery rates above 92% in tap, river, and wastewater samples. Offering simplicity and low cost compared to conventional analytical methods, this nanocomposite electrode provides a robust and scalable solution for real-time environmental monitoring of antibiotic pollutants.