Open AccessTargeting Fluorescent Nanodiamonds to Vascular Endothelial Growth Factor Receptors in Tumor
Author(s) -
Marco D. Torelli,
Ashlyn G. Rickard,
Marina V. Backer,
Daria Filonov,
Nicholas Nunn,
Alexander Kinev,
Joseph M. Backer,
Gregory M. Palmer,
Olga Shenderova
Publication year - 2019
Publication title -
bioconjugate chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.279
H-Index - 172
eISSN - 1520-4812
pISSN - 1043-1802
DOI - 10.1021/acs.bioconjchem.8b00803
Subject(s) - chemistry , receptor , fluorescence lifetime imaging microscopy , angiogenesis , vascular endothelial growth factor , conjugate , in vivo , biocompatibility , cancer research , kinase insert domain receptor , fluorescence , biophysics , microbiology and biotechnology , pathology , biochemistry , vascular endothelial growth factor a , vegf receptors , medicine , biology , mathematical analysis , physics , mathematics , organic chemistry , quantum mechanics
The increased expression of vascular endothelial growth factor (VEGF) and its receptors is associated with angiogenesis in a growing tumor, presenting potential targets for tumor-selective imaging by way of targeted tracers. Though fluorescent tracers are used for targeted in vivo imaging, the lack of photostability and biocompatibility of many current fluorophores hinder their use in several applications involving long-term, continuous imaging. To address these problems, fluorescent nanodiamonds (FNDs), which exhibit infinite photostability and excellent biocompatibility, were explored as fluorophores in tracers for targeting VEGF receptors in growing tumors. To explore FND utility for imaging tumor VEGF receptors, we used click-chemistry to conjugate multiple copies of an engineered single-chain version of VEGF site-specifically derivatized with trans-cyclooctene (scVEGF-TCO) to 140 nm FND. The resulting targeting conjugates, FND-scVEGF, were then tested for functional activity of the scVEGF moieties through biochemical and tissue culture experiments and for selective tumor uptake in Balb/c mice with induced 4T1 carcinoma. We found that FND-scVEGF conjugates retain high affinity to VEGF receptors in cell culture experiments and observed preferential accumulation of FND-scVEGF in tumors relative to untargeted FND. Microspectroscopy provided unambiguous determination of FND within tissue by way of the unique spectral shape of nitrogen-vacancy induced fluorescence. These results validate and invite the use of targeted FND for diagnostic imaging and encourage further optimization of FND for fluorescence brightness.