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scVEGF Microbubble Ultrasound Contrast Agents
| Content Provider | Scilit |
|---|---|
| Author | Anderson, Christopher R. Rychak, Joshua J. Backer, Marina Backer, Joseph Ley, Klaus Klibanov, Alexander L. |
| Copyright Year | 2010 |
| Description | Journal: Investigative radiology Objective: To develop a novel microbubble (MB) ultrasound contrast agent covalently coupled to a recombinant single-chain vascular endothelial growth factor construct (scVEGF) through uniform site-specific conjugation for ultrasound imaging of tumor angiogenesis. Methods: Ligand conjugation to maleimide-bearing MB by thioether bonding was first validated with a fluorophore (BODIPY-cystine), and covalently bound dye was detected by fluorometry and flow cytometry. MBs were subsequently site-specifically conjugated to cysteine-containing Cys-tag in scVEGF, and bound scVEGF was quantified by enzyme-linked immunosorbent assay. Targeted adhesion of scVEGF-MB was investigated with in vitro parallel plate flow chamber assays with recombinant murine VEGFR-2 substrates and human VEGFR-2-expressing porcine endothelial cells (PAE/KDR). A wall-less ultrasound flow phantom, with flow channels coated with immobilized VEGFR-2, was used to detect adhesion of scVEGF-MB with contrast ultrasound imaging. A murine model of colon adenocarcinoma was used to assess retention of scVEGF-MB with contrast ultrasound imaging during tumor angiogenesis in vivo. Results: Proof-of-principle of ligand conjugation to maleimide-bearing MB was demonstrated with a BODIPY-cysteine fluorophore. Conjugation of BODIPY to MB saturated at 10-fold molar excess BODIPY relative to maleimide groups on MB surfaces. MB reacted with scVEGF and led to the conjugation of 1.2 × 105 molecules scVEGF per MB. Functional adhesion of sc-VEGF-MB was shown in parallel plate flow chamber assays. At a shear stress of 1.0 dynes/cm2, scVEGF-MB exhibited 5-fold higher adhesion to both recombinant VEGFR-2 substrates and VEGFR-2-expressing endothelial cells compared with nontargeted control MB. Additionally, scVEGF-MB targeted to immobilized VEGFR-2 in an ultrasound flow phantom showed an 8-fold increase in mean acoustic signal relative to casein-coated control channels. In an in vivo model of tumor angiogenesis, scVEGF MB showed significantly higher ultrasound contrast signal enhancement in tumors (8.46 ± 1.61 dB) compared with nontargeted control MB (1.58 ± 0.83 dB). Conclusions: These results demonstrate the functionality of a novel scVEGF-bearing MB contrast agent, which could be useful for molecular imaging of VEGFR-2 in basic science and drug discovery research. |
| Related Links | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3426362/pdf |
| Ending Page | 585 |
| Page Count | 7 |
| Starting Page | 579 |
| ISSN | 00209996 |
| e-ISSN | 15360210 |
| DOI | 10.1097/rli.0b013e3181efd581 |
| Journal | Investigative radiology |
| Issue Number | 10 |
| Volume Number | 45 |
| Language | English |
| Publisher | Ovid Technologies (Wolters Kluwer Health) |
| Publisher Date | 2010-10-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: Investigative radiology Ultrasound Molecular Imaging Targeted Microbubbles Tumor Angiogenesis Imaging Vegf Receptors Single-chain Vegf |
| Content Type | Text |
| Resource Type | Article |
| Subject | Radiology, Nuclear Medicine and Imaging |
