Anti-quenching NIR-II molecular fluorophores for in vivo high-contrast imaging and pH sensing.

ABSTRACT: The contrast and sensitivity of in vivo fluorescence imaging has been revolutionized by molecular fluorophores operating in the second near-infrared window (NIR-II; 1000-1700?nm), but an ongoing challenge is the solvatochromism-caused quenching in aqueous solution for the long-wavelength absorbing fluorophores. Herein, we develop a series of anti-quenching pentamethine cyanine fluorophores that significantly overcome the severe solvatochromism, thus affording stable absorption/emission beyond 1000?nm with up to?~?44-fold enhanced brightness and superior photostability in aqueous solution. These advantages allow for deep optical penetration (8?mm) as well as high-contrast and highly-stable lymphatic imaging superior to clinical-approved indocyanine green. Additionally, these fluorophores exhibit pH-responsive fluorescence, allowing for noninvasive ratiometric fluorescence imaging and quantification of gastric pH in vivo. The results demonstrate reliable accuracy in tissue as deep as 4?mm, comparable to standard pH electrode method. This work unlocks the potential of anti-quenching pentamethine cyanines for NIR-II biological applications.

SUBMITTER: Wang S 

PROVIDER: S-EPMC6401027 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature