Anthracyclines rank among the most efficacious anticancer medications. However, their clinical utility and oncologic efficacy are severely compromised by the cardiotoxicity risk facing the early-diagnosis difficulty and their unclear molecular mechanism. Herein, a two-photon-excitable and near-infrared-emissive fluorescent probe, TPNIR-FP, was fabricated and endowed with extraordinary specificity and sensitivity and a rapid response toward peroxynitrite (ONOO), as well as mitochondria-targeting ability. With the aid of TPNIR-FP, we demonstrate that mitochondrial ONOO is upregulated in the early stage and contributes to the onset and progression of anthracycline cardiotoxicity in cardiomyocyte and mouse models; therefore, it represents an early biomarker to predict subclinical cardiotoxicity induced by drug challenge. Furthermore, TPNIR-FP is proved to be a robust imaging tool to provide critical insights into drug-induced cardiotoxicity and other ONOO-related pathophysiological processes.

Lyso-TPFP presents lysosomal targetability and an acidic pH-activatable response toward formaldehyde. Thus, it exclusively visualizes lysosomal formaldehyde and is immune against it in neutral cytosol and other organelles. In addition, two-photon fluorescence imaging endows Lyso-TPFP with the capability of in situ tracking formaldehyde in live cells and animals.

We present a feasible paradigm of developing original fluorescent probes for target biomolecules via combinatorial chemistry. In this developmental program, pyrimidine moieties were investigated and optimized as unique recognition units for thiols for the first time through a parallel synthesis in combination with a rapid screening process. This time-efficient and cost-saving process effectively facilitated the developmental progress and provided detailed structure-reactivity relationships. As a result, Res-Biot and Flu-Pht were identified as optimal fluorescent probes for biothiol and thiophenol, respectively. Their favorable characteristics and superior applicability have been well demonstrated in both chemical and biological contexts. In particular, Res-Biot enables the direct visualization of biothiol fluctuations during oxidative stress and cell apoptosis, indicating its suitability in elucidation of a specific pathophysiological process in both living cells and living animals. Meanwhile, Flu-Pht is competent to visualize thiophenols without the interference from endogenous biothiols in living cells.

Endoplasmic reticulum (ER) is the indispensable organelle in eukaryotic cells involving in proteins synthesizing, processing, as well as calcium storage and release. The maintaining of ER quality is of great...