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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.


Synthesis and absorbance properties of NIR-active pHPMAs.
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fig05: Synthesis and absorbance properties of NIR-active pHPMAs.

Mentions: Our synthetic strategy for preparing this unique NIR-active hydrophilic polymer stems from the modularity of its polymeric precursor, poly(pentafluorophenyl methacrylate) (pPFMA), which can be synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization to produce well-defined, telechelic, and unimodal polymeric activated esters by bio-friendly metal-free methods.[10] Although the convenient dithioester terminus can be used as the chelating moiety that binds to the gold surface,[11] it can be reduced to a thiol with sodium borohydride to form thiol-terminated pPFMA (see Supporting Information) so a stronger covalent Au=S bond can be formed.[12] The labile ester bond of the air- and moisture-stable pPFMA can be easily cleaved in the presence of an amine and a base at ambient temperatures to give a multitude of microstructures (Scheme 1).[13] The pPFMA is also an alternative precursor to pHPMA, an established hydrophilic polymer with exceptional circulation properties and drug delivery capabilities.[14] We embarked on employing aniline-modified heptamethine cyanine dyes as our NIR-active conjugates, which were facilely synthesized by the treatment of commercially available IR-780, IR-806, or IR-820 with 4-aminothiophenol.[15] The dyes were then installed onto the polymer by aminolysis of the activated ester linkage on pPFMA in the presence of triethylamine. These reactions were monitored by taking aliquots and observing pentafluorophenol liberation by 19F NMR spectroscopy. Subsequently, addition of excess 2-hydroxypropylamine ensured complete conversion into the dye-modified pHPMAs (IR-pHPMA). Previously, methods used to create analogous polymers have included conjugating dyes to pHPMA polymers by hydrazide linkages, but these routes require extra synthetic steps, such as protection/deprotection chemistry, call for the use of expensive dyes, and do not include terminal sulfurous linkages suitable for gold bonding.[16]


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)

Synthesis and absorbance properties of NIR-active pHPMAs.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig05: Synthesis and absorbance properties of NIR-active pHPMAs.
Mentions: Our synthetic strategy for preparing this unique NIR-active hydrophilic polymer stems from the modularity of its polymeric precursor, poly(pentafluorophenyl methacrylate) (pPFMA), which can be synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization to produce well-defined, telechelic, and unimodal polymeric activated esters by bio-friendly metal-free methods.[10] Although the convenient dithioester terminus can be used as the chelating moiety that binds to the gold surface,[11] it can be reduced to a thiol with sodium borohydride to form thiol-terminated pPFMA (see Supporting Information) so a stronger covalent Au=S bond can be formed.[12] The labile ester bond of the air- and moisture-stable pPFMA can be easily cleaved in the presence of an amine and a base at ambient temperatures to give a multitude of microstructures (Scheme 1).[13] The pPFMA is also an alternative precursor to pHPMA, an established hydrophilic polymer with exceptional circulation properties and drug delivery capabilities.[14] We embarked on employing aniline-modified heptamethine cyanine dyes as our NIR-active conjugates, which were facilely synthesized by the treatment of commercially available IR-780, IR-806, or IR-820 with 4-aminothiophenol.[15] The dyes were then installed onto the polymer by aminolysis of the activated ester linkage on pPFMA in the presence of triethylamine. These reactions were monitored by taking aliquots and observing pentafluorophenol liberation by 19F NMR spectroscopy. Subsequently, addition of excess 2-hydroxypropylamine ensured complete conversion into the dye-modified pHPMAs (IR-pHPMA). Previously, methods used to create analogous polymers have included conjugating dyes to pHPMA polymers by hydrazide linkages, but these routes require extra synthetic steps, such as protection/deprotection chemistry, call for the use of expensive dyes, and do not include terminal sulfurous linkages suitable for gold bonding.[16]

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.