Naphthalimide based fluorescent organic nanoparticles in selective sensing of Fe and as a diagnostic probe for Fe/Fe transition

• Published in: Journal of materials chemistry. B, Materials for biology and medicine Vol. 9; no. 2; pp. 494 - 57
• Main Authors: Sarkar, Deblina, Chowdhury, Monalisa, Das, Prasanta Kumar
• Format: Journal Article
• Published: 21.01.2021
• DOI: 10.1039/d0tb02450c
• ISSN: 2050-750X

Fluorescent organic nanoparticles (FONPs) have attracted considerable attention as a practical and effective platform for sensing and imaging applications. The present article delineates the fabrication of FONPs derived from the naphthalimide based histidine appended amphiphile, NID . The self-assembly of NID in 99 vol% water in DMSO led to the formation of FONPs through J-type aggregation. Aggregation-induced emission (AIE) was observed due to the pre-associated excimer of NID with bluish green emission at 470 nm along with intramolecular charge transfer (ICT). The emission of NID FONPs was utilized for selective sensing of Fe 3+ and bioimaging of Fe 3+ inside mammalian cells. The fluorescence intensity of the FONPs was quenched with the gradual addition of Fe 3+ due to the formation of a 1 : 1 stoichiometric complex with the histidine residue of NID . The morphology of the FONPs transformed from spherical to spindle upon the complex formation of NID with Fe 3+ . The limit of detection (LOD) of this AIE based turn-off chemosensor for Fe 3+ was found to be 12.5 ± 1.2 μM having high selectivity over other metal ions. On the basis of the very low cytotoxicity and selective sensing of Fe 3+ , NID FONPs were successfully employed for bioimaging of Fe 3+ ions through fluorescence quenching within mammalian cells (NIH3T3, B16F10). Considering the varying oxidative stress inside different cells, NID FONPs were used for detecting Fe 2+ to Fe 3+ redox state transition selectively inside cancer cells (B16F10) in comparison to non-cancerous cells (NIH3T3). Selective sensing of cancer cells was substantiated by co-culture experiment and flow cytometry. Hence, NID FONPs can be a selective diagnostic probe for cancer cells owing to their higher H 2 O 2 content. Bluish green emitting fluorescent organic nanoparticles (FONPs) with AIE showed selective sensing of Fe 3+ with a LOD of 12.5 ± 1.2 mM and was exploited in bio-imaging and detection of Fe 2+ /Fe 3+ transition inside cancer cells due to their high H 2 O 2 content.