Multiplexed imaging of surface enhanced Raman scattering nanotags in living mice using noninvasive Raman spectroscopy

Abstract

Raman spectroscopy is a newly developed, noninvasive preclinical imaging technique that offers picomolar sensitivity and multiplexing capabilities to the field of molecular imaging. In this study, we demonstrate the ability of Raman spectroscopy to separate the spectral fingerprints of up to 10 different types of surface enhanced Raman scattering (SERS) nanoparticles in a living mouse after s.c. injection. Based on these spectral results, we simultaneously injected the five most intense and spectrally unique SERS nanoparticles i.v. to image their natural accumulation in the liver. All five types of SERS nanoparticles were successfully identified and spectrally separated using our optimized noninvasive Raman imaging system. In addition, we were able to linearly correlate Raman signal with SERS concentration after injecting four spectrally unique SERS nanoparticles either s.c. (R 2 ‫؍‬ 0.998) or i.v. (R 2 ‫؍‬ 0.992). These results show great potential for multiplexed imaging in living subjects in cases in which several targeted SERS probes could offer better detection of multiple biomarkers associated with a specific disease.imaging in vivo ͉ multiplex ͉ SERS ͉ nanoparticles I n recent years, the biomedical research community has come to realize that no single targeting agent is likely to provide sufficient information needed to characterize or detect a specific disease process. As a result, several efforts have been made toward the discovery of multiple biomarkers and targeting ligands in the hope of improving earlier detection and management of specific diseases. The ability to simultaneously detect multiple targets, sensitively and in vivo, is an attractive feat; but it is a task often difficult to accomplish. Thus far, nanoparticles have played an important role in this endeavor; however most nanostructure-based platforms for multiplex detection methods have been tailored for in vitro applications (1-6), leading to little progress in the field of in vivo multiplex imaging.Recently, there has been an overwhelming interest in sensitive imaging of nanoparticles for both diagnostic and therapeutic applications (7-11). As a result, new preclinical imaging modalities optimized for nanoparticle imaging have been developed, further expanding the field of molecular imaging. Thus far, fluorescence and Raman spectroscopy, in conjunction with quantum dots and surface enhanced Raman scattering (SERS) nanoparticles, respectively, have been the predominant imaging modalities to evaluate in vivo multiplex imaging (12)(13)(14). Raman imaging, in particular, has generated quite a bit of interest recently; we have demonstrated its ability to detect picomolar concentrations in vivo along with its unique ability to multiplex using SERS nanoparticles and others have developed novel Raman nanoparticles with the potential to be used in vivo as well (14-17).Both quantum dots and SERS nanoparticles have shown great potential as multiplexed imaging probes ex vivo, whether for cellular imaging or for biosensor applications; however, seve...

Towardsin vivointradermal surface enhanced Raman scattering (SERS) measurements: silver coated microneedle based SERS probe

“…Moreover, the detection sensitivity is limited by the small Raman scattering cross section (10 -29 -10 -32 cm 2 ) of endogenous biomolecules [5]. In contrast, surface-enhanced Raman scattering (SERS) technique can amplify Raman signals up to 10 14 folds using metallic surfaces [e.g., silver (Ag) and gold] [6]. The SERS strategy has also demonstrated in vivo Raman measurements with penetration deeper than 700 mm, but the subcutaneous injection of metal nanoparticles can be toxic [7].…”

Spectral pre and post processing for infrared and Raman spectroscopy of biological tissues and cells

“…The second method uses a factor analysis algorithm to generate the component spectra, the weighted sum of which is compared to the Raman spectral data set. Using the latter of the two methods, Zavaleta et al demonstrated the power of the technique to quantify quantum dot accumulation in an in-vivo mouse model and to separate out the different spectral contributions from complex SERS signals in the same data set [91].…”

Optical Imaging for Stem Cell Differentiation to Neuronal Lineage

“…To detect diverse markers of neuronal lineage commitment simultaneously, nanomaterials emitting different optical signals might be combined with multiplex imaging techniques. Remarkable progress in the development of nanoparticles for in vitro multiplex analysis has made in vivo multiplex imaging more plausible [48][49][50].…”

“…A recent study involving in vivo Raman spectroscopy [48] showed that ten different Raman signals could be separated from the signals acquired in vivo using [52] different types of SERS nanoprobes (120-nm particles) injected into subcutaneous sites. Simultaneous visualization of multiple nanoprobes with single imaging acquisition is therefore possible.…”