Molecular Diagnosis of Plasma Phenylalanine in Neonates with Phenylketonuria Disease Using Biological Sensors Based on Surface-Enhanced Raman Spectroscopy (SERS)

In this study, silver nanoparticles were chemically synthesized and deposited on glass substrates using a reducing agent of sucrose, at 50°C. Different characterizations including atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and Raman spectroscopy were obtained to study silvery substrates. Then, the silvery substrates were used as the SERS substrates to detect vibrational modes of phenylalanine amino acid up to the concentration of 10-7 M. The importance of phenylalanine amino acid detection is due to the early diagnosis of phenylketonuria in neonates. Therefore, the blood plasma of a healthy neonate and a neonate with phenylketonuria disease were adsorbed on the SERS substrates. They enhance the intensity of molecular vibration peaks of phenylalanine amino acid of two kinds of blood plasmas. The intensities of molecular vibrations of unhealthy plasma are stronger than healthy plasma due to the higher concentrations of phenylalanine amino acid, which is the sign of Phenylketonuria disease.