Surface-Enhanced Raman Scattering Biosensor Based on Self-Assembled Gold Nanorod Arrays for Rapid and Sensitive Detection of Tyrosinase

Tyrosinase (TYR) is a key rate-limiting enzyme of melanin and a biomarker for melanoma diagnosis. Therefore, detection of TYR in biological samples is essential for the clinical diagnosis of melanoma. A novel portable surface-enhanced Raman scattering (SERS) sensor is proposed to detect TYR activity. It is based on dopamine (DA)-functionalized Au nanorod (Au NR) arrays as the capture substrate and 4-mercaptophenylboronic acid (4-MPBA)-modified silver nanoparticles (Ag NPs) as the SERS probe. In this case, the Au NR arrays are modified with 3,3'- dithiodipropionic acid di(N-succinimide ester) (DSP) to capture DA. In the presence of TYR, DA is oxidized to dopaquinone (DQ), which resulted in a decrease in the concentration of SERS probes further adsorbed onto the arrays. The activity of TYR is detected by changes in the intensity of the phenylboronic acid signal. Furthermore, this detection system has a wide linear detection range and high sensitivity that can effortlessly evaluate a linear range of 0.0001-100 U/mL of TYR activity. More significantly, the presented SERS sensor can perform well on both the determination of TYR activity in serum and the assessment of TYR inhibitors, which offers new opportunities for diagnosis of melanoma and other TYR-related diseases under complex biological conditions.