Ultrasound-modulated fluorescence based on fluorescent microbubbles.
J Biomed Opt
; 19(8): 085005, 2014 Aug.
Article
em En
| MEDLINE
| ID: mdl-25104407
ABSTRACT
Ultrasound-modulated fluorescence (UMF) imaging has been proposed to provide fluorescent contrast while maintaining ultrasound resolution in an optical-scattering medium (such as biological tissue). The major challenge is to extract the weakly modulated fluorescent signal from a bright and unmodulated background. UMF was experimentally demonstrated based on fluorophore-labeled microbubble contrast agents. These contrast agents were produced by conjugating N-hydroxysuccinimide (NHS)-ester-attached fluorophores on the surface of amine-functionalized microbubbles. The fluorophore surface concentration was controlled so that a significant self-quenching effect occurred when no ultrasound was applied. The intensity of the fluorescent emission was modulated when microbubbles were oscillated by ultrasound pulses, presented as UMF signal. Our results demonstrated that the UMF signals were highly dependent on the microbubbles' oscillation amplitude and the initial surface fluorophore-quenching status. A maximum of â¼42% UMF modulation depth was achieved with a single microbubble under an ultrasound peak-to-peak pressure of 675 kPa. Further, UMF was detected from a 500-µm tube filled with contrast agents in water and scattering media with ultrasound resolution. These results indicate that ultrasound-modulated fluorescent microbubble contrast agents can potentially be used for fluorescence-based molecular imaging with ultrasound resolution in the future.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Sonicação
/
Microbolhas
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Imagem Molecular
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Técnicas Fotoacústicas
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Corantes Fluorescentes
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Microscopia de Fluorescência
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article