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A "schizophotonic" all-in-one nanoparticle coating for multiplexed SE(R)RS biomedical imaging.

Iacono P, Karabeber H, Kircher MF - Angew. Chem. Int. Ed. Engl. (2014)

Bottom Line: Traditional synthetic routes require high metal-dye affinities and are challenged by unfavorable electrostatic interactions and limited scalability.The integration of various SERS reporters into a biocompatible polymeric surface coating allows for controlled dye incorporation, high colloidal stability, and optimized in vivo circulation times.We demonstrate the capability of this all-in-one gold surface coating and SERS reporter for multiplexed lymph-node imaging.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Center for Molecular Imaging and Nanotechnology (CMINT), Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, NY 10065 (USA).

No MeSH data available.


a) Raman spectra (1 nm aqueous colloid, 1 mW laser power [785 nm], 1 s acquisition time), and b) corresponding multiplexed SERS images of Au@IR-pHPMA and its analogues, including its 19 nm gold-core variant.
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fig02: a) Raman spectra (1 nm aqueous colloid, 1 mW laser power [785 nm], 1 s acquisition time), and b) corresponding multiplexed SERS images of Au@IR-pHPMA and its analogues, including its 19 nm gold-core variant.

Mentions: Figure 2 shows the differences in SERS spectra of the three different nanoprobes as well as their corresponding SERS images, attesting to their in vitro multiplexing capabilities. Because IR-pHPMA-a absorbs closer to the wavelength of the 785 nm laser (ca. 720 nm) than the other two analogues by approximately 60 nm, we observed a much stronger Raman signal as a result of resonance Raman scattering (SERRS). Figure 3 a shows how a slight variance in dye content influences the Raman spectra using a 785 nm laser at 5 mW laser power. As smaller gold nanoparticles are surface coated with IR-pHPMA, the intrinsic fluorescence becomes more prominent (Figure 3 b,c) while shrouding SERS signatures owing to distal polymer-appended dye molecules that are not affected by the gold’s quenching electric field.[23] Because dye molecules are randomly conjugated throughout the polymer, electromagnetic SERS enhancement is optimal within 2–3 nm of the gold surface and decreases as an inverse function of the radius of the gold sphere and dye–surface distance.[24] Some lower-frequency background fluorescence can be imaged with Au@IR-pHPMA even with the larger gold nanospheres, but the bulk of the polymers’ inherent fluorescence, which overlaps with the Raman spectral window, is expectedly quenched by the gold nanoparticle. Figure 3 e shows that the free polymer exhibits a notable near-infrared fluorescence (NIRF) and no SERS signal, whereas its gold-bound analogue exhibits a weakly visible NIRF signal and a highly amplified SERS signal. We have coined the term “schizophotonic” to describe the polymers’ ability to split emission types while anchored to the gold surface. Furthermore, to our knowledge, the ability to produce SERS-active nanoparticles as small as 19 nm has not been previously reported.


A "schizophotonic" all-in-one nanoparticle coating for multiplexed SE(R)RS biomedical imaging.

Iacono P, Karabeber H, Kircher MF - Angew. Chem. Int. Ed. Engl. (2014)

a) Raman spectra (1 nm aqueous colloid, 1 mW laser power [785 nm], 1 s acquisition time), and b) corresponding multiplexed SERS images of Au@IR-pHPMA and its analogues, including its 19 nm gold-core variant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4389888&req=5

fig02: a) Raman spectra (1 nm aqueous colloid, 1 mW laser power [785 nm], 1 s acquisition time), and b) corresponding multiplexed SERS images of Au@IR-pHPMA and its analogues, including its 19 nm gold-core variant.
Mentions: Figure 2 shows the differences in SERS spectra of the three different nanoprobes as well as their corresponding SERS images, attesting to their in vitro multiplexing capabilities. Because IR-pHPMA-a absorbs closer to the wavelength of the 785 nm laser (ca. 720 nm) than the other two analogues by approximately 60 nm, we observed a much stronger Raman signal as a result of resonance Raman scattering (SERRS). Figure 3 a shows how a slight variance in dye content influences the Raman spectra using a 785 nm laser at 5 mW laser power. As smaller gold nanoparticles are surface coated with IR-pHPMA, the intrinsic fluorescence becomes more prominent (Figure 3 b,c) while shrouding SERS signatures owing to distal polymer-appended dye molecules that are not affected by the gold’s quenching electric field.[23] Because dye molecules are randomly conjugated throughout the polymer, electromagnetic SERS enhancement is optimal within 2–3 nm of the gold surface and decreases as an inverse function of the radius of the gold sphere and dye–surface distance.[24] Some lower-frequency background fluorescence can be imaged with Au@IR-pHPMA even with the larger gold nanospheres, but the bulk of the polymers’ inherent fluorescence, which overlaps with the Raman spectral window, is expectedly quenched by the gold nanoparticle. Figure 3 e shows that the free polymer exhibits a notable near-infrared fluorescence (NIRF) and no SERS signal, whereas its gold-bound analogue exhibits a weakly visible NIRF signal and a highly amplified SERS signal. We have coined the term “schizophotonic” to describe the polymers’ ability to split emission types while anchored to the gold surface. Furthermore, to our knowledge, the ability to produce SERS-active nanoparticles as small as 19 nm has not been previously reported.

Bottom Line: Traditional synthetic routes require high metal-dye affinities and are challenged by unfavorable electrostatic interactions and limited scalability.The integration of various SERS reporters into a biocompatible polymeric surface coating allows for controlled dye incorporation, high colloidal stability, and optimized in vivo circulation times.We demonstrate the capability of this all-in-one gold surface coating and SERS reporter for multiplexed lymph-node imaging.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Center for Molecular Imaging and Nanotechnology (CMINT), Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, NY 10065 (USA).

No MeSH data available.