Cu@Au self-assembled nanoparticles as SERS-active substrates for (bio)molecular sensing

Abstract

Cu 0 (core)-Au 0 (shell) (Cu@Au) bimetallic nanoparticles (NPs) synthesized under microwaveassisted heating were interrogated for surface enhanced Raman scattering (SERS)-active substrates. NPs characterization, by XRD, XPS and UV/vis spectroscopy, showed the formation of self-assembled particles with the occurrence of electron transfer from Cu to Au and the absence of CuxO. TEM and AF4 demonstrated NPs with a mean diameter of 4.7 nm. Despite the low LSPR shown by small nanoparticles (< 10 nm diameter), our Cu@Au NPs showed enhanced SERS effect, demonstrated by the calculated scattering signal enhancement factor (3 x 10 5 ), which may be related to electromagnetic coupling. Selected examples of analytes of interest, including some biomolecules, were studied to demonstrate the versatility of our Cu@Au NPs as SERS-active substrates.

Hollow AuxCu1–x Alloy Nanoshells for Surface-Enhanced Raman-Based Tracking of Bladder Cancer Cells Followed by Triggerable Secretion Removal

“…33 Upon formation of a Au-rich AuCu alloy layer, the free-standing AuCu (i.e., Au 0.86 Cu 0.14 ) alloy nanoshells in the solution could increase the chemical mechanism (CE)-and electromagnetic mechanism (EM)-assisted SERS, improving it to 671 and 785 nm, respectively, which is better than that of Ag-, Au-, and AuAg-based NPs. This SERS enhancement is different from the previous SERS results with Au x Cu 1−x solid-state SERS substrates [8][9][10][11]23,27,34,35 relying on gap-and surface roughness-based hot spots at 514 and 632.8 nm, respectively. A SERS nanoprobe combined with nearinfrared (IR) light excitation is a growing analytical method for bio-detection without thermal effects to destroy molecules and favorable molecule detection to avoid fluorescence interference.…”

Gold nanoparticle-based optical nanosensors for food and health safety monitoring: recent advances and future perspectives

“… 296 In addition, Cu@Au NPs exhibited a great potential to be appropriate SERS substrates for various biomolecules, including acetaminophen, dopamine, cholesterol, etc. 290 Furthermore, the complex core–shell alloy structure of Au@Ag–Au NPs showed the best performance compared with core–shell (Au@Ag NPs), alloy (Ag–Au NPs) and mono-metallic structures (AuNPs) in SERS sensing system for cardiac troponin I, a biomarker for cardiac injury. 292 …”

A V(iii)-induced metallogel with solvent stimuli-responsive properties: structural proof-of-concept with MD simulations

“…To relieve these restrictions, different compounds ranging from nanomaterials to supramolecular polymers with this perspective, have been demonstrated [22][23][24][25][26] though the use of gels and metal-organic framework-based materials is very limited. [27][28][29][30] Self-assembly of low molecular weight gelators (LMWGs) has led to a sweet of so materials in the area of drug delivery systems, tissue engineering scaffolds, cosmetics, indicators, and sensors.…”