title: A simple and compact smartphone accessory for quantitative chemiluminescence-based lateral flow immunoassay for salivary cortisol detection.
abstract: We have developed a simple and accurate biosensor based on a chemiluminescent (CL)-lateral flow immunoassay (LFIA) method integrated in a smartphone to quantitatively detect salivary cortisol. The biosensor is based on a direct competitive immunoassay using peroxidase-cortisol conjugate, detected by adding the chemiluminescent substrate luminol/enhancer/hydrogen peroxide. The smartphone camera is used as light detector, for image acquisition and data handling via a specific application. We 3D-printed simple accessories to adapt the smartphone. The system comprises a cartridge, which houses the LFIA strip, and a smartphone adaptor with a plano-convex lens and a cartridge-insertion slot. This provides a mini-darkbox and aligned optical interface between the camera and the LFIA membrane for acquiring CL signals. The method is simple and fast, with a detection limit of 0.3 ng/mL. It provides quantitative analysis in the range of 0.3-60 ng/mL, which is adequate for detecting salivary cortisol in the clinically accepted range. It could thus find application in the growing area of home-self-diagnostic device technology for clinical biomarker monitoring, overcoming the current difficulties in achieving sensitive and quantitative information with conventional systems taking the advantage of smartphone connectivity and the enhanced performance of the included camera.
authors.affiliation: Department of Chemistry, Alma Mater Studiorum - University of Bologna, Via Selmi 2, 40126 Bologna, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Zangheri
authors.affiliation: Department of Chemistry, Alma Mater Studiorum - University of Bologna, Via Selmi 2, 40126 Bologna, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Cevenini
authors.affiliation: Department of Chemistry, University of Turin, Via P. Giuria 5, 10125 Turin, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Anfossi
authors.affiliation: Department of Chemistry, University of Turin, Via P. Giuria 5, 10125 Turin, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Baggiani
authors.affiliation: Department of Medical and Surgical Sciences, Alma Mater Studiorum - University of Bologna, Via Massarenti 9, 40138 Bologna, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Simoni
authors.affiliation: Department of Chemistry, University of Turin, Via P. Giuria 5, 10125 Turin, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Di Nardo
authors.affiliation: Department of Chemistry, Alma Mater Studiorum - University of Bologna, Via Selmi 2, 40126 Bologna, Italy. Electronic address: aldo.roda@unibo.it.
authors.forename: Aldo
authors.initials: A
authors.lastname: Roda
mesh_terms: D015374:Biosensing Techniques / Q000191:economics / Q000295:instrumentation; D040421:Cell Phone / Q000191:economics / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D007118:Immunoassay / Q000191:economics / Q000295:instrumentation*; D057230:Limit of Detection; D008163:Luminescent Measurements / Q000191:economics / Q000295:instrumentation*; D019095:Point-of-Care Systems / Q000191:economics; D012463:Saliva / Q000737:chemistry*
chemical_list: D006854:Hydrocortisone
keywords: Biosensor; Chemiluminescence; Cortisol; Lateral flow immunoassay; Point-of-care; Smartphone