Aggregation of nanoparticles in endosomes and lysosomes produces surface-enhanced Raman spectroscopy (original) (raw)
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Surface Enhanced Raman Spectroscopy and Intracellular Components
Proceedings
In the last decade, surface-enhanced Raman spectroscopy (SERS) met increasing interest in the detection of chemical and biological agents due to its rapid performance and ultra-sensitive features. SERS is a combination of Raman spectroscopy and nanotechnology; it includes the advantages of Raman spectroscopy, providing rapid spectra collection, small sample sizes, and characteristic spectral fingerprints for specific analytes. In this paper, we detected label-free SERS signals for arbitrarily configurations of dimers, trimers, etc., composed of gold nanoshells (AuNSs) and applied to the mapping of osteosarcoma intracellular components.
Langmuir, 2019
Surface-enhanced Raman scattering (SERS) based-single cell analysis is an emerging approach to obtain molecular level information from molecular dynamics in a living cell. In this study, endosomal biochemical dynamics was investigated based on size and surface chemistry dependent uptake of gold nanoparticles (AuNPs) by on single cells over time using SERS. MDA-MB-231 breast cancer cells were exposed to 13 nm and 50 nm AuNPs and their poly-Adenine oligonucleotide modified forms by controlling the order and combination of AuNPs. The average spectra obtained from 20single cells were analyzed to study the nature of the biochemical species or processes taking place on the AuNPs surfaces. The spectral changes, especially from proteins and lipids of endosomal vesicles, were observed depending on the size, surface chemistry, and combination of AuNPs as well as the duration of the AuNP-treatment. The results demonstrate that the SERS spectra are sensitive to trace biochemical changes not only the size, surface chemistry and aggregation status of AuNPs but also their endosomal routematuration steps over time, which can be simple and fast way for understanding the AuNPs behavior in single cell and useful for the assisting and controlling understanding of AuNPs-based gene or drug delivery applications.
Analytical and bioanalytical chemistry, 2014
The cellular response to nanoparticle exposure is essential in various contexts, especially in nanotoxicity and nanomedicine. Here, 14-nm gold nanoparticles in 3T3 fibroblast cells are investigated in a series of pulse-chase experiments with a 30-min incubation pulse and chase times ranging from 15 min to 48 h. The gold nanoparticles and their aggregates are quantified inside the cellular ultrastructure by laser ablation inductively coupled plasma mass spectrometry micromapping and evaluated regarding the surface-enhanced Raman scattering (SERS) signals. In this way, both information about their localization at the micrometre scale and their molecular nanoenvironment, respectively, is obtained and can be related. Thus, the nanoparticle pathway from endocytotic uptake, intracellular processing, to cell division can be followed. It is shown that the ability of the intracellular nanoparticles and their accumulations and aggregates to support high SERS signals is neither directly relate...
In vivo tumor targeting and spectroscopic detection with surface-enhanced Raman nanoparticle tags
Nature Biotechnology, 2008
We describe biocompatible and nontoxic nanoparticles for in vivo tumor targeting and detection based on pegylated gold nanoparticles and surface-enhanced Raman scattering (SERS). Colloidal gold has been safely used to treat rheumatoid arthritis for 50 years, and has recently been found to amplify the efficiency of Raman scattering by 14-15 orders of magnitude. Here we show that large optical enhancements can be achieved under in vivo conditions for tumor detection in live animals. An important finding is that small-molecule Raman reporters such as organic dyes were not displaced but were stabilized by thiolmodified polyethylene glycols. These pegylated SERS nanoparticles were considerably brighter than semiconductor quantum dots with light emission in the near-infrared window. When conjugated to tumor-targeting ligands such as single-chain variable fragment (ScFv) antibodies, the conjugated nanoparticles were able to target tumor biomarkers such as epidermal growth factor receptors on human cancer cells and in xenograft tumor models.
Combining Immunolabeling and Surface-Enhanced Raman Spectroscopy on Cell Membranes
ACS Nano, 2011
We applied surface-enhanced Raman spectroscopy (SERS) to immunolabeled endothelial cells to derive enhanced spectra of the biomolecular makeup of the cellular surface. A two-step immunolabeling protocol with gold-conjugated antibodies coupled with silver enhancement to attach silver nanoparticles to the cell surface was employed. This approach generated ∼50fold SERS enhancement of spectral signals. The SERS spectra exhibited several SERS-enhanced peaks associated with cell membrane components. The SERS detection of silver nanoparticles proved more far more sensitive than conventional light microscopy techniques. The SERS enhancement allowed us to carry out spectral mapping using wavenumbers associated with membrane components that correlated directly with the distribution of silver nanoparticles. SERS has the potential to detect immunolabeling at lower levels than is possible using conventional immunolabeling methods while simultaneously providing unique, spatially defined, biochemical information.
Nanoscale, 2018
In this work, we demonstrate the targeted diagnosis of immunomarker programmed death ligand 1 (PD-L1) and simultaneous detection of epidermal growth factor receptor (EGFR) in breast cancer tumors in vivo using gold nanostars (AuNS) with multiplexed surface enhanced Raman spectroscopy (SERS). Real-time longitudinal tracking with SERS demonstrated maximum accumulation of AuNS occurred 6 h post intravenous (IV) delivery, enabling detection of both biomarkers simultaneously. Raman signal correlating to both PD-L1 and EGFR decreased by ∼30% in control tumors where receptors were pre-blocked prior to AuNS delivery, indicating both the sensitivity and specificity of SERS in distinguishing tumors with different levels of PD-L1 and EGFR expression. Our in vivo study was combined with the first demonstration of ex vivo SERS spatial maps of whole tumor lesions that provided both a qualitative and quantitative assessment of biomarker status with near cellular-level resolution. High resolution S...
Intracellularly grown gold nanoparticles as potential surface-enhanced Raman scattering probes
Journal of Biomedical Optics, 2007
Gold nanoparticles grown within the intracellular confines of living cells are introduced as potential surface-enhanced Raman scattering ͑SERS͒ substrates for confocal Raman spectrometry. Electron microscopy and a silver-enhanced reflectance laser scanning confocal microscopic approach were used to visualize the size, shape, and distribution of intracellularly grown gold nanoparticles ͑IGAuN͒ as small as 1 nm. Passive uptake as the conventional approach for delivering nanoparticles inside cells faces the insurmountable challenge of escaping the endosomal/lysosomal pathway. In contrast, IGAuN provides an unprecedented advantage of providing access to cytoplasm and nucleus.
Gold nanoparticles as a substrate in bio-analytical near-infrared surface-enhanced Raman scattering
The Analyst, 2015
As biospectroscopy techniques continue to be developed for screening or diagnosis within a point-of-care setting, an important development for this field will be high-throughput optimization. For many of these techniques, it is therefore necessary to adapt and develop parameters to generate a robust yet simple approach delivering high-quality spectra from biological samples. Specifically, this is important for surface-enhanced Raman spectroscopy (SERS) wherein there are multiple variables that can be optimised to achieve an enhancement of the Raman signal from a sample. One hypothesis is that "large" diameter (>100 nm) gold nanoparticles provide a greater enhancement at near-infrared (NIR) and infrared (IR) wavelengths than those <100 nm in diameter. Herein, we examine this notion using examples in which SERS spectra were acquired from MCF-7 breast cancer cells incubated with 150 nm gold nanoparticles. It was found that 150 nm gold nanoparticles are an excellent material for NIR/IR SERS. Larger gold nanoparticles may better satisfy the theoretical restraints for SERS enhancement at NIR/IR wavelengths compared to smaller nanoparticles. Also, larger nanoparticles or their aggregates are more readily observed via optical microscopy (and especially electron microscopy) compared to smaller ones. This allows rapid and straightforward identification of target areas containing a high concentration of nanoparticles and facilitating SERS spectral acquisition. To some extent, these observations appear to extend to biofluids such as blood plasma or (especially) serum; SERS spectra of such biological samples often exhibit a low signal-to-noise ratio in the absence of nanoparticles. With protein-rich biofluids such as serum, a dramatic SERS effect can be observed; although this might facilitate improved spectral biomarker identification in the future, it may not always improve classification between control vs. cancer. Thus, use of "large" gold nanoparticles are a good starting point in order to derive informative NIR/IR SERS analysis of biological samples.
Applied Spectroscopy, 2012
The optical properties of PEGylated gold nanorods (PEG-GNR) in interaction with cells have been investigated with Raman and fluorescence microspectroscopic imaging. The emission spectra were compared with those from suspensions of GNR, which can be characterized by a broad emission bandwidth of approximately 60 nm with a band maximum around 675 nm. These properties are in good agreement with observations from various other gold substrates and (nano)particles. The emission spectra from cells incubated with PEG-GNR were dominated by Raman scattering from locations where no GNR were present. Intense fluorescence spectra, in peak-amplitude comparable with the Raman scattering from cells, were observed from locations with GNR. The frequency range of the fluorescence emission spectra coincided mainly with the Raman fingerprint region from 500 cm-1 to 1800 cm-1, excited by the laser emission line at 647.1 nm. No surface enhanced Raman spectra were observed. It was furthermore observed from cluster analysis of the Raman and fluorescence hyperspectral datasets that the GNRrelated integrated fluorescence emission band from an individual cell could be subdivided in multiple bands with slightly varying band maxima. Raman difference spectra of cells with GNR minus control cells showed that the amplitude of lipid signal in PEG-GNR-incubated cells was increased. An excellent correlation occurred between the increased lipid signals and locations of the nanorods. This positive correlation between Raman signals from lipids and fluorescence signals from gold nanorods supports that gold nanorods are locally accumulating in lipid vesicles within the cells.
Nanoprobes for intracellular and single cell surface-enhanced Raman spectroscopy (SERS)
Journal of Raman Spectroscopy, 2012
Surface-enhanced Raman spectroscopy (SERS) is a promising and powerful label free technique for high resolution analysis of single cells. For intracellular analysis, there is a need for SERS-active nanoprobes that are minimally invasive to cells, do not affect cell viability, and provide reproducible signals. This work reviews the state-of-the-art tools currently available for intracellular SERS. Various types of SERS probes are considered, including colloidal gold and silver nanoparticles, metallized optical fibers, and tip-enhanced Raman probes. We also discuss recently developed SERS-active nanopipettes implemented on the basis of pulled glass microcapillaries. Finally, the critical aspects of selecting an optimal SERS nanoprobe for single-cell analysis depending on a particular application are summarized.