Immunoassay of Tumor Markers Based on Graphene Surface-Enhanced Raman Spectroscopy

Abstract

With a unique chemical enhancement capability, graphene oxide is exceptionally suitable to serve as an alternative surface-enhanced Raman scattering (SERS) substrate, which is usually defined as GERS. However, such a GERS matrix with both promising uniformity and molecule enrichment ability has not been applied in the quantitative detection of tumor markers. Herein, an ultrasensitive and specific immunoassay of carcinoembryonic antigens mediated by the GERS matrix was demonstrated. With the assistance of Au NRs as immunoprobes, a reliable limit of detection as low as 3.01 pg/mL was finally achieved because of the collective effect of chemical and electromagnetic enhancements. Meanwhile, a calibration curve with a high R 2 value of 0.996 was obtained in the range from 1 μg/mL to 10 pg/mL. These results exhibit that the GERS matrix has a great promise for participating in immunoassay, which may pave a potential avenue for the real utilization of the SERS technique in clinical biomedicine.

Plasma-Treated Graphene Surfaces for Trace Dye Detection Using Surface-Enhanced Raman Spectroscopy

“…RhB on GO and RGO exhibits a higher enhancement of Raman signals as compared to other dye molecules. The Raman scattering cross-section of RhB is larger as compared to the other dyes; it is another result of RhB exhibiting a higher SERS effect than other dyes . The sensitivity of both GO and RGO to detect RhB molecules is very high, which can be traced down to 10 –8 M. Therefore, the RhB dye is studied using the gas plasma-treated GO and RGO samples to improve its SERS sensitivity.…”

“…Ling et al first observed the effect of graphene on Raman signals in which many unknown peaks emerged when the graphene substrate was treated with an organic solvent as compared to that of the SiO 2 /Si substrate. Several other studies have reported the sensing efficiency of the graphene-based sheet through enhancement of the Raman signal. − Jin-Ha Choi et al demonstrated the reliability of graphene-hybrid (gold array) as the SERS sensing substrate developed by laser interference lithography and the electrochemical deposition method for detecting 10 –4 to 10 –9 M concentration of dopamine. A single molecule (10 –15 M) of rhodamine 6G was detected by using a three-dimensional GO quantum sensor with an enhancement factor (EF) of 10 14 times .…”

Surface modification for improving immunoassay sensitivity

“…146 Recently, Jiang and co-workers developed a GO-based ultrasensitive SERS substrate for CEA detection. 147 By utilizing gold nanorods as immunoprobes, this GO enhanced SERS platform provided a dynamic linear range from 10 pg mL −1 to 1 μg mL −1 with an LOD of 3.01 pg mL −1 for CEA detection. 147…”

Light-Induced Dynamic Assembly of Gold Nanoparticles in a Lab-on-Fiber Platform for Surface-Enhanced Raman Scattering Detection

“…7 Traditional SERS substrates commonly have gold or silver nanostructures on rigid flat-based materials such as silicon wafer and glass slides. 8,9 But, this kind of SERS substrate is difficult to integrate with other devices and lacks flexibility, which severely limits its further applications. With the rapid development of nanotechnology, more functional materials, such as capillary, 10 filter paper, 11 and microfiber, 12,13 have received enormous attention from researchers and have been used in the fabrication of SERS substrates.…”

“…Surface-enhanced Raman spectroscopy (SERS) is one of the sensitive techniques with the possibility of single-molecule detection arising from fingerprint vibration spectrum. ,, It is well known that the enhancement of Raman scattering is driven by chemical and/or electromagnetic interactions, which are mainly manipulated by the metal nanostructures of the SERS substrates . Traditional SERS substrates commonly have gold or silver nanostructures on rigid flat-based materials such as silicon wafer and glass slides. , But, this kind of SERS substrate is difficult to integrate with other devices and lacks flexibility, which severely limits its further applications. With the rapid development of nanotechnology, more functional materials, such as capillary, filter paper, and microfiber, , have received enormous attention from researchers and have been used in the fabrication of SERS substrates.…”