Aptamer-based assay for monitoring genetic disorder phenylketonuria (PKU)

Abstract

The genetic disorder phenylketonuria (PKU) is the inability to metabolize phenylalanine because of a lack of the enzyme phenylalanine hydroxylase. Phenylalanine is used to biochemically form proteins, coded for by DNA. The development of an apta-assay for detection of L-Phenylalanine is presented in this work. A highly specific DNA-aptamer, selected to L-Phenylalanine was immobilized onto a gold nanostructure and electrochemical measurements were performed in a solution containing the phosphate buffer solution with physiological pH. We have constructed an aptamer immobilized gold nanostructure mediated, ultrasensitive electrochemical biosensor (Apt/AuNSs/Au electrode) for L-Phenylalanine detection without any additional signal amplification strategy. The aptamer assemble onto the AuNSs makes Apt/AuNSs/Au electrode an excellent platform for the L-Phenylalanine detection in physiological like condition. Differential pulse voltammetry were used for the quantitative L-Phenylalanine detection. The Apt/AuNSs/Au electrode offers an ultrasensitive and selective detection of L-Phenylalanine down to 0.23 mu M level with a wide dynamic range from 0.72 mu M-6 mM. The aptasensor exhibited excellent selectivity and stability. The real sample analysis was performed by spiking the unprocessed human serum samples with various concentration of L-Phenylalanine and obtained recovery within 2% error value. The sensor is found to be more sensitive than most of the literature reports. The simple and easy way of construction of this apta-assay provides an efficient and promising diagnosis of phenylketonuria. (C) 2018 Published by Elsevier B.V.