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Actively targeted in vivo multiplex detection of intrinsic cancer biomarkers using biocompatible SERS nanotags.

Dinish US, Balasundaram G, Chang YT, Olivo M - Sci Rep (2014)

Bottom Line: However, nanotags without antibodies showed no detectable signal after 6 hours.This difference could be due to the specific binding of the bioconjugated nanotags to the receptors on the cell surface.Thus, this study establishes SERS nanotags as an ultrasensitive nanoprobe for the multiplex detection of biomarkers and opens up its potential application in monitoring tumor progression and therapy and development into a theranostic probe.

View Article: PubMed Central - PubMed

Affiliation: 1] Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), 11 Biopolis Way, Singapore 138667 [2].

ABSTRACT
Surface-enhanced Raman scattering (SERS) technique is becoming highly popular for multiplex biosensing due to the 'fingerprint' Raman spectra from every molecule. As a proof-of-concept, we demonstrated the actively targeted multiplex in vitro and in vivo detection of three intrinsic cancer biomarkers - EGFR, CD44 and TGFβRII in a breast cancer model using three multiplexing capable, biocompatible SERS nanoparticles/nanotags. Intra-tumorally injected antibody conjugated nanotags specifically targeting the three biomarkers exhibited maximum signal at 6 hours and no detectable signal at 72 hours. However, nanotags without antibodies showed no detectable signal after 6 hours. This difference could be due to the specific binding of the bioconjugated nanotags to the receptors on the cell surface. Thus, this study establishes SERS nanotags as an ultrasensitive nanoprobe for the multiplex detection of biomarkers and opens up its potential application in monitoring tumor progression and therapy and development into a theranostic probe.

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Related in: MedlinePlus

In vitro SERS mapping results with three SERS nanotags.(A)- SERS spectra from the cell depicting the multiplexing peak from each nanotag bound to corresponding biomarker on the cell surface and (B)-bright field image of the cell. (C–E) shows the SERS intensity map image demonstrating the expression and relative distribution of the biomarkers- TGFβRII, CD44 and EGFR on the cell surface bound to the antibody conjugated SERS nanotags, Cy5, MGITC and Rh6G respectively. SERS mapping was carried out at 1120 cm−1 peak of Cy5, 1175 cm−1 of MGITC and 1650 cm−1 of Rh6G. (F) SERS intensity map images of the z-series scan at different depth for the Cy5 nanotag (bound to TGFβRII biomarker). Mapping was carried out at a depth interval of 2.5 μm.
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f3: In vitro SERS mapping results with three SERS nanotags.(A)- SERS spectra from the cell depicting the multiplexing peak from each nanotag bound to corresponding biomarker on the cell surface and (B)-bright field image of the cell. (C–E) shows the SERS intensity map image demonstrating the expression and relative distribution of the biomarkers- TGFβRII, CD44 and EGFR on the cell surface bound to the antibody conjugated SERS nanotags, Cy5, MGITC and Rh6G respectively. SERS mapping was carried out at 1120 cm−1 peak of Cy5, 1175 cm−1 of MGITC and 1650 cm−1 of Rh6G. (F) SERS intensity map images of the z-series scan at different depth for the Cy5 nanotag (bound to TGFβRII biomarker). Mapping was carried out at a depth interval of 2.5 μm.

Mentions: After confirming the presence of the three biomarkers - EGFR, CD44 and TGFβRII in the MDA-MB-231 cell line using western blot, the cells were exposed to a mixture of three antibody conjugated SERS nanotags (Rh6G-EGFR, MGITC-Cd44 and Cy5-TGFβRII) to map the biomarkers using SERS. Multiplexed SERS spectra measured from the cell surface is provided in Fig. 3A, while the bright field image of the cells are shown in Fig. 3B. It is obvious that the point spectral measurement from the cell surface clearly indicates the ‘fingerprint’ spectral peak from each of the three nanotags that allows for the multiplex detection of biomarkers. Relative distribution of the intrinsic cancer biomarkers on the cell surafce was obtained by mapping at respective Raman peaks of the SERS nanotag that the antibody to the biomarker is attached to. Fig. 3(C–E) confirm the specific interaction and binding of the bioconjugated nanotags to the three biomarkers on the cell surface. Intensity mapping at 1120 cm−1 (Cy5) demonstrated the localization of the antibody conjugated Cy5 and thus the distribution of TGFβRII. Similarly, the intensity mapping at 1175 cm−1 and at 1650 cm−1 demonstrated the localization of antibody conjugated MGITC and Rh6G nanotags and hence the distribution of CD44 and EGFR respectively. To test the specificity of the antibody conjugated SERS tags, SERS mapping was done on Jurkat cells (that do not express EGFR, CD44 and TGFβRII) exposed to the same mixture of SERS nanotags. SERS images obtained from these cells were dark with few bright (Fig. S5, SI) spots unlike the MDA-MB-231 cells indicating that the tags did not bind to the cell surface because of the absence of the receptors.


Actively targeted in vivo multiplex detection of intrinsic cancer biomarkers using biocompatible SERS nanotags.

Dinish US, Balasundaram G, Chang YT, Olivo M - Sci Rep (2014)

In vitro SERS mapping results with three SERS nanotags.(A)- SERS spectra from the cell depicting the multiplexing peak from each nanotag bound to corresponding biomarker on the cell surface and (B)-bright field image of the cell. (C–E) shows the SERS intensity map image demonstrating the expression and relative distribution of the biomarkers- TGFβRII, CD44 and EGFR on the cell surface bound to the antibody conjugated SERS nanotags, Cy5, MGITC and Rh6G respectively. SERS mapping was carried out at 1120 cm−1 peak of Cy5, 1175 cm−1 of MGITC and 1650 cm−1 of Rh6G. (F) SERS intensity map images of the z-series scan at different depth for the Cy5 nanotag (bound to TGFβRII biomarker). Mapping was carried out at a depth interval of 2.5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921631&req=5

f3: In vitro SERS mapping results with three SERS nanotags.(A)- SERS spectra from the cell depicting the multiplexing peak from each nanotag bound to corresponding biomarker on the cell surface and (B)-bright field image of the cell. (C–E) shows the SERS intensity map image demonstrating the expression and relative distribution of the biomarkers- TGFβRII, CD44 and EGFR on the cell surface bound to the antibody conjugated SERS nanotags, Cy5, MGITC and Rh6G respectively. SERS mapping was carried out at 1120 cm−1 peak of Cy5, 1175 cm−1 of MGITC and 1650 cm−1 of Rh6G. (F) SERS intensity map images of the z-series scan at different depth for the Cy5 nanotag (bound to TGFβRII biomarker). Mapping was carried out at a depth interval of 2.5 μm.
Mentions: After confirming the presence of the three biomarkers - EGFR, CD44 and TGFβRII in the MDA-MB-231 cell line using western blot, the cells were exposed to a mixture of three antibody conjugated SERS nanotags (Rh6G-EGFR, MGITC-Cd44 and Cy5-TGFβRII) to map the biomarkers using SERS. Multiplexed SERS spectra measured from the cell surface is provided in Fig. 3A, while the bright field image of the cells are shown in Fig. 3B. It is obvious that the point spectral measurement from the cell surface clearly indicates the ‘fingerprint’ spectral peak from each of the three nanotags that allows for the multiplex detection of biomarkers. Relative distribution of the intrinsic cancer biomarkers on the cell surafce was obtained by mapping at respective Raman peaks of the SERS nanotag that the antibody to the biomarker is attached to. Fig. 3(C–E) confirm the specific interaction and binding of the bioconjugated nanotags to the three biomarkers on the cell surface. Intensity mapping at 1120 cm−1 (Cy5) demonstrated the localization of the antibody conjugated Cy5 and thus the distribution of TGFβRII. Similarly, the intensity mapping at 1175 cm−1 and at 1650 cm−1 demonstrated the localization of antibody conjugated MGITC and Rh6G nanotags and hence the distribution of CD44 and EGFR respectively. To test the specificity of the antibody conjugated SERS tags, SERS mapping was done on Jurkat cells (that do not express EGFR, CD44 and TGFβRII) exposed to the same mixture of SERS nanotags. SERS images obtained from these cells were dark with few bright (Fig. S5, SI) spots unlike the MDA-MB-231 cells indicating that the tags did not bind to the cell surface because of the absence of the receptors.

Bottom Line: However, nanotags without antibodies showed no detectable signal after 6 hours.This difference could be due to the specific binding of the bioconjugated nanotags to the receptors on the cell surface.Thus, this study establishes SERS nanotags as an ultrasensitive nanoprobe for the multiplex detection of biomarkers and opens up its potential application in monitoring tumor progression and therapy and development into a theranostic probe.

View Article: PubMed Central - PubMed

Affiliation: 1] Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), 11 Biopolis Way, Singapore 138667 [2].

ABSTRACT
Surface-enhanced Raman scattering (SERS) technique is becoming highly popular for multiplex biosensing due to the 'fingerprint' Raman spectra from every molecule. As a proof-of-concept, we demonstrated the actively targeted multiplex in vitro and in vivo detection of three intrinsic cancer biomarkers - EGFR, CD44 and TGFβRII in a breast cancer model using three multiplexing capable, biocompatible SERS nanoparticles/nanotags. Intra-tumorally injected antibody conjugated nanotags specifically targeting the three biomarkers exhibited maximum signal at 6 hours and no detectable signal at 72 hours. However, nanotags without antibodies showed no detectable signal after 6 hours. This difference could be due to the specific binding of the bioconjugated nanotags to the receptors on the cell surface. Thus, this study establishes SERS nanotags as an ultrasensitive nanoprobe for the multiplex detection of biomarkers and opens up its potential application in monitoring tumor progression and therapy and development into a theranostic probe.

Show MeSH
Related in: MedlinePlus