Highly Sensitive and Reproducible SERS Sensor for Biological pH Detection Based on a Uniform Gold Nanorod Array Platform

Abstract

Conventional research on surface-enhanced Raman scattering (SERS)-based pH sensors often depends on nanoparticle aggregation, whereas the variability in nanoparticle aggregation gives rise to poor repeatability in the SERS signal. Herein, we fabricated a gold nanorod array platform via an efficient evaporative self-assembly method. The platform exhibits great SERS sensitivity with an enhancement factor of 5.6 × 10 and maintains excellent recyclability and reproducibility with relative standard deviation (RSD) values of less than 8%. On the basis of the platform, we developed a highly sensitive bovine serum albumin (BSA)-coated 4-mercaptopyridine (4-MPy)-linked (BMP) SERS-based pH sensor to report pH ranging from pH 3.0 to pH 8.0. The intensity ratio variation of 1004 and 1096 cm in 4-MPy showed excellent pH sensitivity, which decreased as the surrounding pH increased. Furthermore, this BMP SERS-based pH sensor was employed to measure the pH value in C57BL/6 mouse blood. We have demonstrated that the pH sensor has great advantages such as good stability, reliability, and accuracy, which could be extended for the design of point-of-care devices.

SERS using two-photon polymerized nanostructures for mycotoxin detection

“…[16][17][18][19][20][21][22] However, the repeatability and reproducibility of SERS measurements with nanoparticles can hardly be guaranteed because of the inhomogeneity of the particles' distributions and shapes. Therefore, nano-pillar arrays, hemisphere arrays, triangle arrays, and other periodical nanostructures have been developed as SERS substrates by means of electrodeposition 9 and nanoimprinting lithography [23][24][25] to improve the repeatability and reproducibility. However, these methods are time consuming and less exible.…”

Detection of Chloroalkanes by Surface-Enhanced Raman Spectroscopy in Microfluidic Chips

“…Influence of pH on the SERS spectrum was observed previously with ionic species such as 4-mercaptobenzoic acid and exploited for pH sensing [ 37 , 38 ]. In such cases, the change in Raman spectra is linked to deprotonation of the analyte molecule and the intermolecular interactions, which can change how effectively the molecules pack on the substrate.…”

Detection of Chloroalkanes by Surface-Enhanced Raman Spectroscopy in Microfluidic Chip

“…Influence of pH on the SERS spectrum was observed previously with ionic species such as 4-mercaptobenzoic acid and exploited for pH sensing [31,32]. In such cases, the change in Raman spectra is linked to deprotonation of the analyte molecule and the intermolecular interactions, which can change how effectively the molecules pack on the substrate.…”