Abstract: A convenient and efficient method to eliminate the aggregation effect of organic photoelectric sensing materials and to improve biological compatibility and cell permeability as well was delved by hanging organic fluorophores on a polymer chain, for example, fluorescein fluorophores had been controllably hanged on polyacrylamide main chains with 1:2 stoichiometric ratio by a simple copolymerization strategy. The results showed that introduction of water-soluble bioactive polyacrylamide main chains into fluorescein fluorophores via covalent bonds could effectively improve their optical stability by deteriorating π-π stack and charge-transfer interaction among different fluorophores. More importantly, the resultant materials possessed low toxicity and excellent cell permeability ten times larger than its precursor fluorescein fluorophore, which made it express an especially turn-on fluorescent response to ultra-trace Hg²⁺ both in aqueous and living cells by forming stable 5-member-ring complexes with Hg²⁺ with a nice correlation coefficient of 0.997 and a low detection limit of 4.0×10⁻¹⁰ mol·L⁻¹. This work would provide a promising insight to construct some practical sensing materials for biological analyses environment-friendly.

Keywords: Polyacrylamide pendant approach; Disaggregation effect; Improved biological compatibility; Cell permeability; ultra-trace Hg²⁺