Activatable Semiconducting Oligomer Amphiphile for Near-Infrared Luminescence Imaging of Biothiols

Abnormal levels of biothiols such as cysteine (Cys) and homocysteine (Hcy) are associated with many pathological diseases. However, most fluorescence probes for biothiols sensing rely on visible fluorescence, which are not optimized for in vivo imaging because of the shallow tissue penetration. We herein synthesize a hydrophobic oligo(phenylenevinylene) (OPV) based semiconducting oligomer amphiphile that can emit both fluorescence and afterglow luminescence and evaluate its ability for detection of biothiols. Such an amphiphile is used to encapsulate a hydrophobic near-infrared (NIR) dye through π-πstacking and hydrophobic interaction to develop a near-infrared (NIR) fluorescence nanoprobe (OPVN0.2). Because the OPV backbone has the benzaldehyde end groups that can specifically react with biothiols, the fluorescence of OPVN0.2 is enhanced in the presence of biothiols; however, its afterglow luminescence of OPVN0.2 remained nearly the same due to the different luminescence mechanism. Such a nanoprobe permits sensitive detection of biothiols both in vitro and in vivo.