An Integrated DNA Nanoprobe for Intranuclear Imaging and in Situ Profiling of OGG1 Activity

Accurate quantification of 8-oxoguanine DNA glycosylase-1 (OGG1) activity in the cell nucleus is crucial for evaluating the DNA oxidative damage marker 8-oxoguanine (8-oxoG). However, due to the difficulty in nuclear localization and the predicament of strong signal output, subcellular imaging has not yet been achieved. Herein, we report a nuclear-targeted DNA triangular prism nanoprobe (TP-SA) designed to overcome the aforementioned limitations via a dual-pronged strategy. TP-SA integrated an AS1411 aptamer for active nucleus delivery and a Förster resonance energy transfer (FRET) array for signal readout. In living cells, TP-SA enabled monitoring of nuclear OGG1 activity, revealing distinct variations in basal enzymatic levels across various cell lines. Additionally, preliminary evaluations in bronchoalveolar lavage fluid from pneumonia patients suggested its applicability in clinical settings. Furthermore, it served as a platform for pharmacological validation, effectively assessing the effects of small-molecule activators on OGG1. This study established a powerful framework for designing spatially specific nanoprobes, successfully enabling intranuclear imaging and in situ profiling of OGG1 activity. This advancement has transcended the boundaries of traditional biosensors, providing powerful and multi-dimensional tools for basic biological sensing, clinical analysis in complex biological fluids, and precision medicine fields.