Dual-color nanospheres based on aggregation-induced emission and catalytic hairpin assembly for simultaneous imaging of acrylamide and miR-21 in living cells

Acrylamide (AA) is a heat-processed potent food carcinogen that is widely used in industry, posing a significant risk to human health. Therefore, it is necessary to investigate the toxic effects and mechanism of AA. miR-21 is a representative biomarker during AA-induced carcinogenesis. Here, dual-color aggregation-induced emission nanoparticles (AIENPs) were developed for the detection and simultaneous imaging of AA and miR-21. AIENPs were synthesized by combining aggregation-induced emission (AIE) dyes and a poly (styrene-co-maleic anhydride) (PSMA) amphiphilic polymer modified with hairpin DNA. Upon AA intervention and aptamer recognition, cDNA was dissociated, leading to miR-21 overexpression and initiating the catalytic hairpin assembly cycle. Consequently, fluorescence quenching was observed due to FRET between AIENPs and labeled quenchers. The relative fluorescence intensities of dual-color AIENPs displayed good linear relationships with logarithmic AA and miR-21 concentrations. Moreover, there was a gradual decrease in dual-color AIENP fluorescence as the HepG2 cell concentration of AA (0-500 μM) and stimulation time (0-12 h) increased, making it possible to simultaneously image AA and AA-induced miR-21. The findings of this work are valuable for revealing the cytotoxic mechanism of AA.