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. 2010 Jan;10(1):250-4.
doi: 10.1021/nl903411s.

Photo-targeted Nanoparticles

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Free PMC article

Photo-targeted Nanoparticles

Tal Dvir et al. Nano Lett. .
Free PMC article

Abstract

We report a novel and simple proof-of-concept of a nanoparticulate system that targets any tissue selectively upon illumination. Nanoparticles were covalently functionalized with the amino acid sequence YIGSR, which adheres to the beta1 integrins present on most cell surfaces. This peptide was masked with a caging group, rendering it biologically inert. Illumination with UV light released the caging group from the YIGSR, allowing binding to cells.

Figures

Figure 1
Figure 1
The photo-targeted nanoparticle concept. A non-specific ligand on the surface of the nanoparticles is caged, rendering it non-functional. Upon illumination, the caging group is released, the ligand is activated and the nanoparticle can bind to the illuminated tissue. The lower portion of the figure shows the chemistry of the targeting moiety as it relates to the events schematized above. The GGGGYIGSR-NH2 peptide is caged on tyrosine with a 4,5-dimethoxy-2-nitrobenzyl group (DMNB, Blue). After illumination the caging group is released and the targeter becomes active.
Figure 2
Figure 2
Expression of integrin β1 (green) on endothelial (A) and mesenchymal stem (B) cells. Cell nuclei are stained in blue. Bar = 10 μm.
Figure 3
Figure 3
HPLC chromatogram of (A) non-caged peptide, (B) non-illuminated caged peptide, and (C) caged peptide after 1 minute illumination.
Figure 4
Figure 4
Release of the caging group from the nanoparticles. (A) The disappearance of the ether bond on the targeter as assessed by FTIR. (B) Release of free DMNB caging group from nanoparticles modified with Y(DMNB)IGSR.
Figure 5
Figure 5
Nanoparticle targeting. (A) Attachment of nanoparticles with caged YIGSR peptide to HUVECs in illuminated and non-illuminated cultures. The particles appear white. (B) Percentage of HUVECs and MSCs targeted by nanoparticles. The nanoparticles were labeled according the type of surface ligand: “Non-caged”: YIGSR, “Caged”: Y(DMNB)IGSR, “Non-ad” the non-adhering peptide (FHPDYRVI).
Figure 6
Figure 6
Targeting of HUVECs. (A) Macroscopic view under UV illumination of fluorescent nanoparticles adhering specifically to cells in a small area that had been illuminated at 340 nm for 1 minute (arrow). (B) and (C) Microscopic views of the cells in the illuminated area (B) or located 1 cm away (C). Cell cytoplasm was stained with β actin antibody (green), nuclei stained by Hoechst (blue) and the nanoparticles appear red. Bar = 100 μm.

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