Selectivity

Detection limit

Monomer

Nanotechnology

Organic chemistry

Methacrylic acid

Ethylene glycol dimethacrylate

Colloidal gold

Plasmon

Methacrylate

Catalysis

Nanoparticle

Composite material

Chemistry

Materials science

Methyl methacrylate

Molecular imprinting

Polymerization

Chromatography

Optoelectronics

Polymer

Biosensors

Herein, gold nanoparticles (AuNP)-modified cortisol-imprinted (AuNP-MIP) plasmonic sensor was developed for signal amplification and real-time cortisol determination in both aqueous and complex solutions. Firstly, the sensor surfaces were modified with 3-(trimethoxylyl)propyl methacrylate and then pre-complex was prepared using the functional monomer N-methacryloyl-L-histidine methyl ester. The monomer solution was made ready for polymerization by adding 2-hydroxyethyl methacrylate to ethylene glycol dimethacrylate. In order to confirm the signal enhancing effect of AuNP, only cortisol-imprinted (MIP) plasmonic sensor was prepared without AuNP. To determine the selectivity efficiency of the imprinting process, the non-imprinted (AuNP-NIP) plasmonic sensor was also prepared without cortisol. The characterization studies of the sensors were performed with atomic force microscopy and contact angle measurements. The kinetic analysis of the AuNP-MIP plasmonic sensor exhibited a high correlation coefficient (R2 = 0.97) for a wide range (0.01-100 ppb) with a low detection limit (0.0087 ppb) for cortisol detection. Moreover, the high imprinting efficiency (k' = 9.67) of the AuNP-MIP plasmonic sensor was determined by comparison with the AuNP-NIP plasmonic sensor. All kinetic results were validated and confirmed by HPLC.

Selective Amplification of Plasmonic Sensor Signal for Cortisol Detection Using Gold Nanoparticles