A lateral flow immunoassay for visual detection of prostate-specific antigen (PSA) in food using gold and silver nanocomposite

Diagnostics is of great importance in the medical practice, as only timely diagnosis allows choosing an adequate method of treatment. The use of methods of early diagnostics of diseases is one of the main directions of development of preventive medicine. The prostate carcinoma occupies the first rank for prevalence and the second rank for death rate among oncological diseases of men. The disease is characterized by a slow development and asymptomatic course up to the late stages, which complicates its clinical diagnostics [1, 2]. Now the determination of PSA, an oncomarker, in the samples of blood serum is used for an early diagnostics of this disease. The determination of PSA is the obligatory clinical analysis for men after 50 years in the EU countries and the Unites States. The PSA content in blood serum of healthy men does not exceed 4 ng/ml. Nonmalignant prostate hyperplasia is accompanied by an increase in the PSA level up to 10 ng/ml; at the PSA level above 30 ng/ml, the diagnosis of the prostate carcinoma is confirmed for almost all patients examined. The determination of PSA level is carried out to reveal prostatitis, to monitor the course of the disease, and to control the treatment efficiency. In this study, lateral flow immunoassay (LFA) strip was developed for fast screening of blood samples for prostate-specific antigen (PSA) using the respective monoclonal antibody immobilized on nanoparticles with a silver core and a gold shell (AgAu) as detection reagent. Assay is in sandwich format and uses two specific monoclonal antibodies against PSA, one of which is labeled with AgAu nanoparticles and other is immobilized at test line. The developed biosensor is specific and has a lower detection limit of 0.3 ng/ml. The method may be suitable for testing PSA in blood samples as it is quick, easy to perform and reproducible.