Cellulose-Nanocrystal-Templated Metal–Organic Framework Nanoprobe for Phosphate-Enhanced Cellular Fluorescence Imaging

Abstract

Intracellular fluorescence imaging relies on probes that maintain stable emission in physiological environments; however, many nanoprobes are susceptible to quenching or aggregation, resulting in unreliable signals. To address this issue, we developed a rod-like nanocellulose-crystal-templated fluorescent metal–organic frameworks (MOFs) probe. Dicarboxylated cellulose nanocrystals (DCC) were employed as one-dimensional rigid support to facilitate the in situ growth of fluorescent surface-grown MOF nanodomains. This strategy achieved controlled regulation of MOF nanocrystal size and spatial distribution, while effectively suppressing disordered aggregation. Subsequent grafting of PEG₅₀₀₀-NH₂ significantly improved aqueous colloidal stability as well as enhanced luminescence adaptability under physiological conditions. The resulting nanoprobe exhibited a selective “turn-on” response toward inorganic Pi under physiological conditions with low background and good signal retention, enabling phosphate-enhanced intracellular fluorescence imaging.