Rationally design and create an activatable probe to monitor peroxynitrite in the mice model of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) stands as a formidable global public health challenge, necessitating advanced diagnostic modalities. Herein, we report the development and multifaceted application of HD-ONOO, an innovative hemicyanine-based fluorescent scaffold engineered for the highly selective, real-time monitoring of peroxynitrite (ONOO-)-a pivotal reactive oxygen species (ROS) linked to PCOS pathology. Upon site-specific interaction with ONOO-, the probe undergoes a structured activation process, yielding pronounced enhancements in both its ratiometric-like absorbance and fluorescence emission profiles. This "turn-on" response demonstrates a robust linear dependency on ONOO- concentration, achieving a superior limit of detection (LOD) of 0.03 μM. In vitro assays confirmed that HD-ONOO can faithfully track endogenous ONOO- fluctuations, highlighting its utility for early-stage diagnostics and longitudinal disease surveillance. Crucially, clinical validation using PCOS murine models and corresponding serum samples revealed significantly elevated fluorescence intensity compared to healthy cohorts, reinforcing its prognostic value in assessing PCOS risk. Characterized by exceptional chemo-specificity and physiological stability, HD-ONOO represents a versatile analytical platform for non-invasive monitoring and the optimization of early therapeutic interventions in clinical and biomedical research settings.