Innovative Surface Plasmon Resonance Aptasensor for Detecting Cocaine in Human Urine

• Published in: Analytica 2024-11, Vol.5 (4), p.587-598
• Main Authors: Keklik Şah, Gül, Isbir Turan, Aybüke A.
• Format: Article
• Language: English
• Subjects: aptamer; Biomarkers; Biosensors; Chromatography; Cocaine; Contact angle; Cost analysis; Environmental monitoring; Enzymes; Gold; gold nanoparticle; Homogeneity; Immunoassay; Isotherms; Laboratories; Methods; Nanoparticles; Sensors; surface characterization; Surface plasmon resonance; Surface roughness; synthetic urine; Urine
• ISSN: 2673-4532; 2673-4532
• DOI: 10.3390/analytica5040039

This study describes the development of an optical-based surface plasmon resonance (SPR) aptasensor for the detection of cocaine. The aptasensor was prepared by first attaching gold nanoparticles to a clean SPR chip surface, followed by the addition of an aptamer to create a modified surface. This surface was characterized using contact angle and atomic force microscopy, revealing surface roughness values of 0.28 nm and 28.12 nm for the blank and modified surfaces, respectively. The detection of cocaine was carried out in the concentration range of 1 ng/mL to 1000 ng/mL, with a detection time of approximately 8 min and a cocaine limit of detection (LOD) of 0.43 ng/mL. Repeatability studies were conducted, and the stability of the signal response was examined at a concentration of 200 ng/mL. Adsorption isotherm models, including Scatchard, Langmuir, and Freundlich models, were calculated to assess the surface homogeneity of the SPR aptasensor chip, with the results indicating compatibility with the Langmuir isotherm model.