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An 125I-labeled octavalent peptide fluorescent nanoprobe for tumor-homing imaging in vivo

Paper ID Volume ID Publish Year Pages File Format Full-Text
7275 543 2012 8 PDF Available
Title
An 125I-labeled octavalent peptide fluorescent nanoprobe for tumor-homing imaging in vivo
Abstract

Targeting radiopeptides are promising agents for radio-theranostics. However, in vivo evaluation of their targeting specificity is often obscured by their short biologic half-lives and low binding affinities. Here, we report an approach to efficiently examine targeting radiopeptides with a new class of octavalent peptide fluorescent nanoprobe (Octa-FNP) platform, which is composed of candidate targeting peptides and a tetrameric far-red fluorescent protein (tfRFP) scaffold. To shed light on this process, 125I-Octa-FNP, 125I-tfRFP and 125I-peptide were synthesized, and their targeting functionalities were compared. Both fluorescence imaging and radioactive quantification results confirmed that 125I-Octa-FNP had a significantly higher cellular binding capability than 125I-tfRFP. In vivo biodistribution studies show that at 6 h post-injection, 125I-Octa-FNP had 2-fold and 30-fold higher tumor uptake than that of 125I-tfRFP and 125I-peptide, respectively. Moreover, γ-imaging at 24 h post-injection revealed a remarkable accumulation of 125I-Octa-FNP in the tumor while maintaining an extremely low background contrast, which was further confirmed by immunofluorescence analysis. These data suggested that, as an engineered and multivalent platform, Octa-FNP could enhance the tumor targeting of a designed peptide and provide excellent contrast radioimaging, making it a valuable tool for the evaluation of the targeting ability of specifically designed radiopeptides for cancer theranostics.

Keywords
Far-red fluorescent protein; Targeting peptide; Tetrameric; Protein scaffold; γ-Imaging
First Page Preview
An 125I-labeled octavalent peptide fluorescent nanoprobe for tumor-homing imaging in vivo
Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 33, Issue 19, June 2012, Pages 4843–4850
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering