Fluorogens with Aggregation Induced Emission: Ideal Photoacoustic Contrast Reagents Due to Intramolecular Rotation.
Exogenous contrast agents with high sensitivity are highly desirable for photoacoustic (PA) imaging. In this work, we show that fluorogens with aggregation induced emission (AIE) characteristics are born with strong PA signals. In addition, we find that the PA signal of conventional fluorophores could be significantly enhanced through conjugation with tetraphenylethene (TPE), an iconic AIE fluorogen. Taking 2,3-bis[4-(diphenylamino)phenyl]fumaronitrile (TPAFN) as an example, conjugation between TPAFN and TPE affords 2,3-bis(4-(phenyl(4-(1,2,2-triphenylvinyl)phenyl)amino)phenyl) fumaroni-trile (TPETPAFN), a molecule with significant AIE characteristics, which shows 170% higher PA signals as compared to that of TPAFN. The higher PA signal of TPETPAFN is mainly ascribed to the enhanced molecular rotation, which is beneficial to its thermal expansion upon light absorption. Moreover, the significantly reduced PA signals for TPETPAFN in solvents with high viscosity or as nanoparticles further highlight the contribution of molecular rotation on PA signals.
Junlong
J
Geng
Lun-De
LD
Liao
Wei
W
Qin
Ben Zhong
BZ
Tang
Nitish
N
Thakor
Bin
B
Liu
D003287:Contrast Media / Q000138:chemical synthesis*; D005456:Fluorescent Dyes / Q000737:chemistry*; D007089:Image Enhancement / Q000379:methods*; D008422:Materials Testing; D033401:Microscopy, Acoustic / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D061088:Photoacoustic Techniques / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D005456:Fluorescent Dyes