Synthesis and characterization of water-soluble ultrasound sensitive nanoparticles

Due to their high quantum yields of singlet oxygen and excellent light-induction attributes, hypocrellins have recently received much research attention.[1][2][3] Hypocrellins, including hypocrellin A (HA) and hypocrellin B (HB), have relatively low absorption in the phototherapeutic window (600–900nm) due to their longest wavelength absorbance band at 584nm. To solve this problem, amino groups are introduced into hypocrellin molecules in order to enhance their absorbance in the visible red band. SL052 is a proprietary HB discovered by Quest PharmaTech Inc. in Edmonton, Canada. SL052 demonstraates an absorbance maximum at 635nm[4] due to optimized intra-molecular charge transfers between the amino- and carbonyl groups.[5] We report the use of nanoparticles to make SL052 water soluble while maintaining the intra-molecular charge transfer chemistry.