Construction of HPQ-based activatable fluorescent probe for peroxynitrite and its application in ferroptosis and mice model of LPS-induced inflammation

As one of the important members of reactive oxygen species, ONOO− plays a crucial role in signal transduction, immune response, and other physiological activities. Aberrant changes in ONOO− levels in the living organism are usually associated with many diseases. Therefore, it is important to establish a highly selective and sensitive method for the determination of ONOO− in vivo. Herein, we designed a novel ratio near-infrared fluorescent probe for ONOO− by directly conjugating dicyanoisophorone (DCI) to hydroxyphenyl-quinazolinone (HPQ). Surprisingly, HPQD was unaffected by environmental viscosity and responded rapidly to ONOO− within 40 s. The linear range of ONOO− detection was from 0 μM to 35 μM. Impressively, HPQD did not react with reactive oxygen species and was sensitive to exogenous/endogenous ONOO− in live cells. We also investigated the relationship between ONOO− and ferroptosis and achieved in vivo diagnosis and efficacy evaluation of mice model of LPS-induced inflammation, which showed promising prospects of HPQD in ONOO−-related studies.