Imaging of surface-enhanced Raman scattering (SERS) nanoparticles (NPs) has been intensively studied for cancer detection due to its high sensitivity, unconstrained low signal-to-noise ratios, and multiplexing detection capability. Furthermore, conjugating SERS NPs with various biomarkers is straightforward, resulting in numerous successful studies on cancer detection and diagnosis. However, Raman spectroscopy only provides spectral data from an imaging area without co-registered anatomic context. This is not practical and suitable for clinical applications. Here, we propose a custom-made Raman spectrometer with computer-vision-based positional tracking and monocular depth estimation using deep learning (DL) for the visualization of 2D and 3D SERS NPs imaging, respectively. In addition, the SERS NPs used in this study (hyaluronic acid-conjugated SERS NPs) showed clear tumor targeting capabilities (target CD44 typically overexpressed in tumors) by anex vivoexperiment and immunohistochemistry. The combination of Raman spectroscopy, image processing, and SERS molecular imaging, therefore, offers a robust and feasible potential for clinical applications.
more »
« less
Quantitative Surface-Enhanced Spectroscopy
Surface-enhanced Raman scattering (SERS), a powerful technique for trace molecular detection, depends on chemical and electromagnetic enhancements. While recent advances in instrumentation and substrate design have expanded the utility, reproducibility, and quantitative capabilities of SERS, some challenges persist. In this review, advances in quantitative SERS detection are discussed as they relate to intermolecular interactions, surface selection rules, and target molecule solubility and accessibility. After a brief introduction to Raman scattering and SERS, impacts of surface selection rules and enhancement mechanisms are discussed as they relate to the observation of activation and deactivation of normal Raman modes in SERS. Next, experimental conditions that can be used to tune molecular affinity to and density near SERS substrates are summarized and considered while tuning these parameters is conveyed. Finally, successful examples of quantitative SERS detection are discussed, and future opportunities are outlined.
more »
« less
- Award ID(s):
- 1707859
- PAR ID:
- 10337129
- Date Published:
- Journal Name:
- Annual Review of Physical Chemistry
- Volume:
- 73
- Issue:
- 1
- ISSN:
- 0066-426X
- Page Range / eLocation ID:
- 141 to 162
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Verma, Prabhat; Suh, Yung Doug (Ed.)Advances in nanotechnology enable the detection of trace molecules from the enhanced Raman signal generated at the surface of plasmonic nanoparticles. We have developed technology to enable super-resolution imaging of plasmonic nanoparticles, where the fluctuations in the surface enhanced Raman scattering (SERS) signal can be analyzed with localization microscopy techniques to provide nanometer spatial resolution of the emitting molecule’s location. Additional work now enables the super-resolved SERS image and the corresponding spectrum to be acquired simultaneously. Here we will discuss how this approach can be applied to provide new insights into biological cells.more » « less
-
Surface-enhanced Raman scattering (SERS) provides orders of magnitude of enhancements to weak Raman scattering. The improved sensitivity and chemical information conveyed in the spectral signatures make SERS a valuable analysis technique. Most of SERS enhancements come from the electromagnetic enhancement mechanism, and changes in spectral signatures are usually attributed to the chemical enhancement mechanism. As the electromagnetic mechanism has been well studied, we will give an overview of models related to the chemical mechanism, which explain the Raman response in terms of electronic transitions or induced electron densities. In the first class of models based on electronic transitions, chemical enhancements are attributed to changes in transitions of the molecule and new charge transfer transitions. The second class of models relate chemical enhancements to charge flows near the molecule–metal interface by partitioning the induced electron density of the SERS system in real space. Selected examples will be given to illustrate the two classes of models, and connections between the models are demonstrated for prototypical SERS systems.more » « less
-
Highly sensitive and specific molecular detection is essential for advancing early cancer diagnosis. In this paper, we present an imaging system that combines swept source Raman spectroscopy with surface-enhanced Raman scattering (SERS) nanoparticles to enhance cancer detection capability. By incorporating a high-efficiency superconducting nanowire single-photon detector (SNSPD), the system achieves remarkable detection sensitivity to the femtomolar concentrations. This performance was demonstrated under practical conditions using only 30 mW excitation power and 40 ms wavelength point exposure time, enabling ultra-sensitive acquisition. Imaging experiments on both cell and tissue samples confirm the system’s compatibility with various biological applications. Combining high sensitivity, speed, and specificity, this platform offers a promising approach for molecular imaging and early stage cancer detection using SERS-based probes.more » « less
-
Recently, surface-enhanced Raman scattering (SERS) joined other optical methods in making novel anticounterfeiting materials due to the fact that abundant molecular fingerprints in Raman spectra can be less susceptible to fraud. Using these molecular features, it is critical to make novel nanostructures with increased SERS enhancement and stability. Herein, we synthesized star-shaped gold nanoparticles as SERS substrates and applied various Raman probes with these gold nanostars to make SERS tags. The encoded molecular information was successfully decoded using principal component analysis (PCA). These colloidal tags can be further stabilized when embedded in a polymer matrix. We made a prototype ballpoint pen that can do simple writing with these secret SERS inks.more » « less
An official website of the United States government

