Highly fluorescent conjugated polyelectrolyte for protein sensing and cell-compatible chemosensing applications

Using a highly fluorescent, water-soluble polymer derived from a triazine-bridged copolymer (DTMSPV), we explored the tunable fluorescence properties of the water-soluble DTMSPV by solvent polarity to function as a fluorescence sensory probe for protein sensing. The green-blue fluorescence from DTMSPV was significantly enhanced in the presence of bovine serum albumin through hydrophobic interactions. Meanwhile, complete quenching of the fluorescence from DTMSPV occurred in the presence of hemoglobin through iron complexation with the polyelectrolyte. In addition, the DTMSPVs were highly fluorescent and permeated into living mesenchymal stem cells (MSCs), enabling effective imaging of the MSCs. This permeation into stem cells is crucial to the detection of Al³⁺ in living MSCs. The interaction between the triazine units in DTMSPV with the Al³⁺ ions allows for the detection of Al³⁺ in living cells. Thus, a strong fluorescence from living MSCs pretreated with DTMSPV was quenched as a function of the Al³⁺ concentration, confirming that DTMSPV is a cell-permeable fluorescent polymer that can function as a versatile probe to detect Al³⁺ in living cells.