In the efforts to generate a less toxic X‐Ray bioimaging contrast agent, a fully organic, radioluminescent nanoparticle system that emits in the near‐infrared (NIR) region when excited with an X‐Ray source is synthesized using a two‐step process. First, red‐emitting nanoparticles are fabricated by the emulsion copolymerization of styrene and propargyl acrylate with anthracene, naphthalimide, and rhodamine B methyl methacrylate derivatives. Subsequently, the nanoparticles are modified with silicon phthalocyanine and indocyanine green derivatives via a copper(I)‐catalyzed azide/alkyne cycloaddition “click” reaction. By coupling an organic scintillator with four Förster resonance energy transfer‐pairing dyes, X‐Ray‐induced, multiple, sequential energy transfer is exploited to convert ionizing radiation from an X‐Ray source into NIR light, which is optimal for biomedical imaging. Proof‐of‐concept imaging studies show that the X‐Ray‐induced indocyanine green fluorescence from the particulate system can be visualized through porcine tissue. Additionally, toxicity studies in human embryonic kidney cells indicate that the particles are nontoxic and applicable
Core/shell nanoparticles composed of a silica core over which a propargyl methacrylate (PMA) shell was polymerized around were synthesized. To employ the shell coating, the surface of the silica nanoparticles (SiNPs) was modified with an alkene-terminated organometallic silane linker that allowed for the covalent attachment of a poly(propargyl methacrylate) (pPMA) shell. The alkyne groups resulting from the pPMA shell were utilized in copper(I)-catalyzed azide/alkyne cycloaddition (CuAAC) reactions to attach azide-modified Förster resonance energy transfer (FRET) pairs of naphthalimide (azNap), rhodamine B (azRhod), and silicon phthalocyanine (azSiPc) derivatives to the shell surface. The luminescence of the system was manipulated by the covalent attachment of one, two, or three of the fluorophores resulting in no energy transfer, one energy transfer, or two energy transfers, respectively. When all three fluorophores were attached to the core/shell particles, an excitation of azNap with a wavelength of 400 nm resulted in the sequential energy transfer between two FRET pairs and the sole emission of azSiPc at 670 nm. These particles may have applications as bioimaging probes as their luminescence is easily detected using fluorescence microscopy.
more » « less- Award ID(s):
- 1632881
- PAR ID:
- 10229087
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optical Materials Express
- Volume:
- 11
- Issue:
- 6
- ISSN:
- 2159-3930
- Format(s):
- Medium: X Size: Article No. 1742
- Size(s):
- Article No. 1742
- Sponsoring Org:
- National Science Foundation
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