Seed shape-controlled, facet-selective growth of superspiky gold nanocrystals for biosensing applications

Abstract

Spiky plasmonic Au nanostructures have sparked considerable interest in plasmonic sensing, plasmon-enhanced spectroscopic biosensing and solar energy harvesting, owing to their distinctive complex three-dimensional structures and remarkable optical properties. Seeded...

Near-infrared II plasmonic porous cubic nanoshells for in vivo noninvasive SERS visualization of sub-millimeter microtumors

“…The pc-AuAg NSs with the 945 nm plasmon resonance wavelength (denoted as pc-AuAg NSs-945 nm) have the highest NIR-II SERS EF, while the lowest SERS EF for pc-AuAg NSs with the 1540 nm plasmon resonance wavelength. The maximum NIR-II SERS enhancement takes place at a plasmon resonance wavelength blue-shifting from the laser excitation wavelength (1064 nm) used for the present SERS measurement, which is attributed to the antagonistic interplay between optical extinction and near-field enhancement in SERS enhancement, consistent with our previous reports 40 , 41 . Then, the limit of detection (LOD) of NIR-II SERS detection was estimated using pc-AuAg NSs-945 nm (Supplementary Fig.…”

Additional Important Considerations in Surface-Enhanced Raman Scattering Enhancement Factor Measurements

“…Nevertheless, the experimental measurement of the SERS EF requires accurate determination of the number of probe molecules ( N surf ) adsorbed on the SERS substrate and the number of probe molecules ( N NR ) and normal Raman intensity ( I NR ) in the spontaneous Raman measurement without the SERS substrate. In reality, besides these factors mentioned above, the measurement of the SERS EF is also affected by other factors such as selected vibrational modes, electronic interactions between probe molecules and the substrate, molecular orientation and surface coverage of probe molecules, particulate concentration, incident laser wavelength, and so on. − For the SERS EF calculation, we usually assume a complete surface coverage of probe molecules on the SERS substrate to facilitate the estimation of the number ( N surf ) of probe molecules. However, the surface coverage of probe molecules could greatly vary with the footprint, surface affinity, and initial concentration of probe molecules, posing a big challenge to the accurate estimation of the number of probe molecules.…”

Hybrid Surface-Enhanced Raman Scattering Substrates for the Trace Detection of Ammonium Nitrate, Thiram, and Nile Blue

“…Gold (Au) nanomaterials are the maximum studied nanotechnological tools in diverse fields including surface-enhanced Raman spectroscopy (SERS), catalysis, biosensing, and bioimaging due to easy synthesis methods, chemical stability, biocompatibility, and outstanding optical properties. 1 − 4 Particularly, the localized surface plasmonic resonance (SPR) property of Au nanomaterials can be tuned from the visible to near-infrared region depending on the morphology with respect to the size and shape. 5 − 7 In the recent years, Au nanostars have stimulated enormous attention in the fabrication of SERS substrates because of the induced high electric fields at their sharp tips, unlike their spherical, triangular, and nanorod counterparts.…”

“…Gold (Au) nanomaterials are the maximum studied nanotechnological tools in diverse fields including surface-enhanced Raman spectroscopy (SERS), catalysis, biosensing, and bioimaging due to easy synthesis methods, chemical stability, biocompatibility, and outstanding optical properties. − Particularly, the localized surface plasmonic resonance (SPR) property of Au nanomaterials can be tuned from the visible to near-infrared region depending on the morphology with respect to the size and shape. − In the recent years, Au nanostars have stimulated enormous attention in the fabrication of SERS substrates because of the induced high electric fields at their sharp tips, unlike their spherical, triangular, and nanorod counterparts. − In most of the previous studies, chemically synthesized nanoparticles (NPs) with different shapes were embedded on different substrates, such as glass, silicon, paper(s), fabrics, and so forth, for being used as SERS sensors for the detection of distinct analyte molecules. ,− Recently, a few novel strategies have been demonstrated for patterned SERS substrates coated with NPs of various shapes for the detection of diverse analytes. − The patterned substrates along with NPs with diverse shapes have demonstrated a significant improvement in the detection sensitivity due to the embedded NPs, along with the patterned areas acting as hotspot regions and increasing the SPR strength, resulting in strong electric fields at the confined regions. − Abundant fabrication procedures have been established for fabricating patterned substrates on countless materials, among which short/ultrashort laser ablation is a simple, fast, and efficient fabrication tool for the generation of distinct surface structures on various substrates. − Since the past 2 decades, substantial improvements have been made in achieving diverse nanostructures (NSs) on a wide range of materials such as metals, semiconductors, insulators, and polymers by varying the short/ultrashort laser ablation parameters (pulse duration, wavelength, fluence, number of pulses, and focusing conditions) and surrounding environments (air, gas, and liquid). ,,− The ultrashort laser-induced surface structures have proven to be promising candidates in diverse areas such as sensing, ,− …”