A nanoaggregate-on-mirror platform for molecular and biomolecular detection by surface-enhanced Raman spectroscopy
- 685 Downloads
A nanoaggregate-on-mirror (NAOM) structure has been developed for molecular and biomolecular detection using surface-enhanced Raman spectroscopy (SERS). The smooth surface of the gold mirror allows for simple and homogeneous functionalization, while the introduction of the nanoaggregates enhances the Raman signal of the molecule(s) in the vicinity of the aggregate-mirror junction. This is evidenced by functionalizing the gold mirror with 4-nitrothiophenol, and the further addition of gold nanoaggregates promotes local SERS activity only in the areas with the nanoaggregates. The application of the NAOM platform for biomolecular detection is highlighted using glucose and H2O2 as molecules of interest. In both cases, the gold mirror is functionalized with 4-mercaptophenylboronic acid (4-MPBA). Upon exposure to glucose, the boronic acid moiety of 4-MPBA forms a cyclic boronate ester. Once the nanoaggregates are added to the surface, detection of glucose is possible without the use of an enzyme. This method of indirect detection provides a limit of detection of 0.05 mM, along with a linear range of detection from 0.1 to 15 mM for glucose, encompassing the physiological range of blood glucose concentration. The detection of H2O2 is achieved with optical inspection and SERS. The H2O2 interferes with the coating of the gold mirror, enabling qualitative detection by visual inspection. Simultaneously, the H2O2 reacts with the boronic acid to form a phenol, a change that is detected by SERS.
KeywordsSurface-enhanced Raman spectroscopy Nanoaggregate-on-mirror 4-Mercaptophenylboronic acid Glucose Hydrogen peroxide
The authors gratefully acknowledge the Nanofabrication Facility at Western University. This research was funded by the Canada Research Chairs program in “Photonics and Nanosciences” (F.L.-L.). The authors also acknowledge the Natural Sciences and Engineering Research Council of Canada.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
- 8.De Angelis F, Gentile F, Mecarini F, Das G, Moretti M, Candeloro P, Coluccio ML, Cojoc G, Accardo A, Liberale C, Zaccaria RP, Perozziello G, Tirinato L, Toma A, Cuda G, Cingolani R, Di Fabrizio E (2011) Breaking the diffusion limit with super-hydrophobic delivery of molecules to plasmonic nanofocusing SERS structures. Nat Photonics 5(11):682–687CrossRefGoogle Scholar
- 22.Danaei G, Finucane MM, Lu Y, Singh GM, Cowan MJ, Paciorek CJ, Lin JK, Farzadfar F, Khang Y-H, Stevens GA, Rao M, Ali MK, Riley LM, Robinson CA, Ezzati M (2011) National, regional, and global trends in fasting plasma glucose and diabetes prevalence since 1980: systematic analysis of health examination surveys and epidemiological studies with 370 country-years and 2.7 million participants. Lancet 378(9785):31–40CrossRefGoogle Scholar
- 34.McCreery RL (2005) Magnitude of Raman scattering. In: Raman spectroscopy for chemical analysis. Wiley, pp. 15–33Google Scholar
- 60.Ceja-Fdez A, Lopez-Luke T, Torres-Castro A, Wheeler DA, Zhang JZ, De la Rosa E (2014) Glucose detection using SERS with multi-branched gold nanostructures in aqueous medium. RSC Adv 4(103):59233–59241Google Scholar