Towards selective tetracycline recognition in wastewater based on gold nanovoids@aptamer sensing

In recent years, tetracycline antibiotic residues in food and water have been of great concern to regulators and consumers, with adverse effects on both ecosystems and human health. In this work, we developed a novel 3D honeycombed goldnanovoids@aptamer nanostructured platform with biorecognition and signal enhancement properties for the detection of tetracycline. Direct electrochemical detection was enabled by differential pulse voltammetry through the Ferrocene redox label at the aptamer strands which was effectively influenced by the tetracycline-aptamer specific interaction. The aptasensor can detect tetracycline at a concentration from 1.25∙10−8 M to 1.00∙10−6 M, and the limit of detection and limit of quantification were calculated as 1.20∙10−9 M (0.53 ng/mL) and 4.23∙10−9 M (1.87 ng/mL), respectively. Furthermore, the aptasensor presented excellent selectivity in detecting tetracycline in the presence of various interference analytes. In addition, the proposed sensor proved its practical feasibility to quickly and accurately quantify tetracycline residues in wastewater samples with satisfactory recoveries (from 93.18 to 112.64 %, RSD 1.12 % – 6.13 %). We have designed and synthesized a 3D honeycombed gold nanostructured platform for the highly tailored aptamer functionalization for the specific detection of tetracycline, expanding the range of electrochemical detection aptasensors and offering great promise for in-situ water monitoring.