In vivo cancer imaging by poly(ethylene glycol)-b-poly(ɛ-caprolactone) micelles containing a near-infrared probe

Noninvasive near-infrared (NIR) fluorescence imaging is a promising technique for the intraoperative assessment of solid tumor removal. We incorporated a lipophilic NIR probe, 1,1′-dioctadecyltetramethyl indotricarbocyanine iodide (DiR), in poly(ethylene glycol)-b-poly(ɛ-caprolactone) (PEG-b-PCL) micelles, resulting in DiR solubilization in water, occupying nanoscopic PEG-b-PCL micelles. DiR in a self-quenched or nonquenched state showed different kinetics of release from PEG-b-PCL micelles in vitro; however, both obtained high tumor delineation (tumor-to-muscle ratio of 30–43 from collected organs). These results suggest that PEG-b-PCL micelles with DiR are a promising nanosized imaging agent that will provide a basis for enhanced surgical guidance via NIR visualization of tumors.From the Clinical EditorIn this paper, noninvasive near-infrared fluorescence imaging coupled with specific lipophilic probes is discussed as a promising technique for intraoperative assessment of solid tumor removal, leading to optimized outcomes for in toto removal of tumors.

Graphical AbstractPEG-b-PCL micelles migrated into solid tumors with incorporated DiR in either a non-quenched state (left) or a self-quenched state (right) by the EPR effect, delineating solid tumors. Non-quenched DiR displayed a rapid onset of strong fluorescence intensity at solid tumors. On the other hand, self-quenched DiR displayed relatively lower fluorescence intensity, but a gradual increase over time at solid tumors.Figure optionsDownload high-quality image (214 K)Download as PowerPoint slide