Fabrication and imaging study of ultrasound/fluorescence bi-modal contrast agent based on polymeric microbubbles
10.3760/cma.j.issn.2095-2848.2013.01.004
- VernacularTitle:基于聚合物微泡的超声/荧光双模态造影剂的制备及成像研究
- Author:
Zhanwen XING
;
Hengte KE
;
Jinrui WANG
;
Bo ZHAO
;
Enze QU
;
Xiuli YUE
;
Zhifei DAI
- Publication Type:Journal Article
- Keywords:
Ultrasonography;
Fluorescence imaging;
Microbubbles;
Contrast media;
Microscopy
- From:
Chinese Journal of Nuclear Medicine and Molecular Imaging
2013;(1):14-18
- CountryChina
- Language:Chinese
-
Abstract:
Objective To fabricate an ultrasound/fluorescence bi-modal contrast agent by encapsulating fluorescent quantum dots into polymeric ultrasound contrast agent microbubbles.Methods Polylactic acid (PLA,500 mg),(1R)-(+)-camphor (50 mg) and CdSe/ZnS quantum dots (0.5 ml,2.3 μmol/L)were dissolved or dispersed in dichloromethane (10 ml) to form in an organic phase.Ammonium carbonate solution and poly (vinyl alcohol) solution were employed as the internal and external water phase,respectively.The fluorescent microbubbles were generated using double emulsion solvent evaporation and lyophilization methods.The morphology and illumination were characterized by scanning electron microscopy (SEM) and fluorescence spectrophotometry.Synchronized contrast-enhanced ultrasound and fluorescence imaging was acquired by injecting fluorescent microbubbles into the silicone tube coupled to a self-made ultrasound/fluorescence imaging device.Ultrasound/fluorescence bi-modal in vivo imaging was acquired on the kidney of New Zealand rabbits and suckling mice.Results The fluorescent microbubbles were hollow spheres with an averaged diameter of (1.62 ± 1.47) μm.More than 99％ of these microbubbles were less than 8 μm in diameter,which meeted the size criteria for ultrasound contrast agents.The fluorescence emission peak of the microbubbles appeared at 632 nm,indicating that good luminescence properties of quantum dots were maintained.In vitro ultrasound/fluorescence imaging showed no echoic signal when the silicone tube was filled with saline,but there was a strong echo when filled with fluorescent microbubbles.The liquid column with fluorescent microbubbles emitted red luminescence under ultraviolet irradiation.The kidney of the rabbit was remarkably enhanced after the administration of fluorescent microbubbles.Bright fluorescence could be observed at the injection site of the suckling mice via subcutaneous injection.Conclusions A bi-modal but single contrast agent based on polymeric microbubbles has been successfully fabricated for the use of ultrasound and fluorescence imaging.It retains the good characteristics of both echogenicity and fluorescence,which complement each other in case of limitations imposed by uni-modal,single agents.
