Surface plasmon resonance immunosensor for cortisol and cortisone determination.
In this paper, we present a surface-plasmon-resonance-based immunosensor for the real-time detection of cortisol and cortisone levels in urine and saliva samples. The method proposed here is simple, rapid, economic, sensitive, robust, and reproducible thanks also to the special features of the polycarboxylate-hydrogel-based coatings used for the antibody immobilization. The sensor surface displays a high level of stability during repeated regeneration and affinity reaction cycles. The immunosensor shows high specificity for cortisol and cortisone; furthermore, no significant interferences from other steroids with a similar chemical structure have been observed. The suitability of the hydrogel coating for the prevention of nonspecific binding is also investigated. A good correlation is noticed between the results obtained by the proposed method and the reference liquid chromatography/tandem mass spectrometry method for the analysis of cortisol and cortisone in urine and saliva samples. Standard curves for the detection of cortisol and cortisone in saliva and urine are characterized by a detection limit less than 10 microg l(-1), sufficiently sensitive for both clinical and forensic use.
Frasconi
Marco
M
Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Rome, Italy.
Mazzarino
Monica
M
Botrè
Francesco
F
Mazzei
Franco
F
D055910:Antibodies, Immobilized / Q000737:chemistry; D003348:Cortisone / Q000032:analysis* / Q000276:immunology / Q000652:urine; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000276:immunology / Q000652:urine; D020100:Hydrogels / Q000737:chemistry; D007118:Immunoassay / Q000191:economics / Q000379:methods*; D011108:Polymers / Q000737:chemistry; D012463:Saliva / Q000737:chemistry; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000191:economics / Q000379:methods*
D055910:Antibodies, Immobilized; D020100:Hydrogels; D011108:Polymers; D003348:Cortisone; D006854:Hydrocortisone