# Synergistic InSe quantum dots–mesoporous Ta2O5 nanostructure for ultrasensitive electrochemical detection of antibiotics in environmental samples

## TL;DR

A new sensor using InSe quantum dots and mesoporous Ta2O5 detects antibiotics in water with high sensitivity and accuracy.

## Contribution

A synergistic InSe QD–mesoporous Ta2O5 nanostructure is developed for ultrasensitive antibiotic detection in environmental samples.

## Key findings

- The sensor achieves a detection limit of ∼2.5 × 10−11 M for antibiotics like tetracycline and ciprofloxacin.
- The sensor shows excellent stability over 30 days and recovery rates above 92% in various water samples.
- The combination of InSe QDs and Ta2O5 provides high electrocatalytic activity and selectivity.

## Abstract

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.

InSe QD/Ta2O5-modified GCE enables ultrasensitive detection of antibiotics with an LOD of ∼2.6 × 10−11 M. Its mesoporous structure and high electrocatalytic activity ensure rapid response and excellent selectivity.