Abstract:
Solid-state surface-enhanced Raman spectroscopic
(SERS) substrates surmount the limitations of colloidal nanoparticles for many practical chemical and biomolecular sensors.
The main bottom-up approaches adopted for SERS substrate
fabrication include preparing plasmonic nanoparticles and their
deposition to selected surfaces via chemical self-assembly, inkjet
printing, spray coating, dip-coating, etc. In contrast, the top-down
strategy is to create nanostructures on surfaces via different
lithographic techniques (nanoimprint lithography, electron beam
lithography), laser ablation, or chemical etching and then
depositing a nanolayer of coinage metals. The ease and
reproducibility of production, high enhancement, and uniformity
of performance are the requirements for a reliable SERS substrate. This work describes an easy process for preparing SERS substrates
from a less expensive and readily available material, brass. The treatment of brass with hydrochloric acid caused preferential etching
of Zn from the surface, leaving a uniform Cu nanoporous substrate (CuNPS). The subsequent galvanic displacement of CuNPS with
AgNO3 resulted in silver nanocrystal overgrowth, as evidenced by microscopic, spectroscopic, and elemental studies. The
corresponding SERS studies with 4-mercaptophenylboronic acid (4-MPBA) as the probe molecule revealed ∼30 and ∼300 times
improved performance compared to CuNPS and the parent brass substrates, respectively. Further, we explored the possibility of
sensing creatinine, the biomarker for kidney functioning. Creati
