Highly emissive dibenzofuranfluorophores with aggregation-induced emission for bioimaging in HeLa cell lines

Dibenzo[b,d]furans, structural analogs of furan, represent an emerging class of promising molecules whose solid-state emission properties remain largely unexplored. The aim of the present work is to design and synthesize new dibenzo[b,d]furan-based organic fluorophores for bioimaging applications. The synthesis involved a single-step Schiff base reaction of 4-(dibenzo[b,d]furan-4-yl)aniline with two different ortho-hydroxy aldehydes, furnishing DBF1 and DBF2 in high yields. Both fluorophores DBF1 and DBF2 exhibited high fluorescence in their solid and aggregated states. The photophysical properties in solution, solid, and aggregated states were investigated using absorbance and emission spectroscopy. The aggregation process was confirmed by the particle size analysis using dynamic light scattering (DLS). The cytotoxicity of the molecules was investigated against HeLa cell lines by the standard MTT assay. DBF1 and DBF2 demonstrated exceptional photoluminescence with quantum yields reaching up to 17.89% and 2.26% respectively, highlighting their potential as excellent materials for imaging applications. Both DBF1 and DBF2 exhibited significant toxicity towards HeLa cells with IC₅₀ values of 42.08 μg ml^-1 and 39.74 μg ml^-1, respectively, showcasing notable anti-proliferative activity against HeLa cells. Both fluorophores exhibited excellent emission in HeLa cells with mean relative fluorescence intensities of 1.008 ± 0.77 a.u. and 1.44 ± 0.65 a.u. for DBF1 and DBF2, respectively. Thus, this work presents the lesser explored dibenzo[b,d]furan-based organic fluorophores for bioimaging applications with potential inhibitory activity against HeLa cells.