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Gold Nanorod Etching for Sensitive Aptamer-Mediated Colorimetric Detection of Escherichia Coli in Water Publisher



Namjoo F1 ; Shalileh F1 ; Golbashy M2 ; Sabahi H3 ; Hosseini M1, 4
Authors
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Authors Affiliations
  1. 1. Nanobiosensors Lab, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Iraq
  2. 2. Department of Plant Production and Genetics Engineering, College of Agriculture, Agricultural Sciences and Natural Resources, University of Khuzestan, Mollasani, Iraq
  3. 3. Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran, Iran
  4. 4. Medical Biomaterials Research Center, Tehran University of Medical Sciences, Tehran, Iran

Source: Microchemical Journal Published:2025


Abstract

Herein, we have introduced a novel aptamer-based biosensor for E.coli detection in water, using the intriguing optical properties of gold nanorods (AuNRs). Aptamer-functionalized AuNRs are partially protected from etching by varying E. coli concentrations. However, in the presence of E. coli, the aptamer detaches, exposing the nanorod's surface to the etchant mixture containing optimized amounts and concentrations of CTAB, H2O2, CuSO4, KBr, and H2SO4. This exposure leads to rapid etching of the AuNRs in both longitudinal and transverse axes, proportional to the E. coli concentration in the samples. The etching process causes an obvious blue shift in the AuNRs spectra which is also accompanied by the gradual color change of the sample. This method demonstrated high sensitivity for E. coli, with a limit of detection (LOD) of 7 CFU/mL and a response time of 10 min. It exhibited a linear response in the range of 10–106 CFU/mL and promising selectivity for E. coli detection with the capability of detection in real water samples. © 2024 Elsevier B.V.
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