Advanced nanocellulose-based electrochemical sensor for tetracycline monitoring

Antibiotics play a pivotal role in healthcare and agriculture, but their overuse and environmental presence pose critical challenges. Developing sustainable and effective detection methodologies is crucial to mitigating antibiotic resistance and environmental contamination. This study presents a cellulosic polymer-based electrochemical sensor by integrating TEMPO-oxidized cellulose nanofibers-polyethyleneimine hybrids (TOCNFs-PEI) with single-walled carbon nanotube networks (SWCNTs). Our research focuses on (i) conducting physicochemical and electrochemical studies of multifunctional SWCNT/TOCNFs-PEI architectures, (ii) elucidating the relationships between the material's properties and their electrochemical performance, and (iii) assessing its performance in detecting tetracycline concentrations in both controlled and more complex matrices (treated wastewater effluents). The limits of detection were evaluated to be 0.180 µmol L⁻¹ (at the potential of 0.85 V) and 0.112 µmol L⁻¹ (at the potential of 0.65 V) in phosphate-buffered saline solution, and 2.46 µmol L⁻¹ (at the potential of 0.82 V) and 1.5 µmol L⁻¹ (at the potential of 0.65 V) in the undiluted membrane bioreactor effluent sample, respectively. Further, the designed cellulosic polymer-based sensing architecture is compatible with large-scale production, paving the way for a new era of green, versatile sensing devices. These developments will significantly contribute to global efforts to alleviate antibiotic resistance and environmental contamination.