Synthesis and spectroscopic properties of a new fluorescent acridine hyperbranched polymer: Applications to acid sensing and as antimicrobial agent

Abstract

The synthesis of a hyperbranched polyesteramide functionalized with 6 acridine groups (P1000-ACRID) is described, and its photophysical properties compared with its low molecular weight reference compound (ACRIDyne). The hyperbranched polymer does not show aggregation of the acridine groups neither in solution nor in solid polymer matrices. The behavior of both chromophores as fluorescent acid sensors has been studied in solution and in solid polymer films, showing an increase in their fluorescence emission. The stoichiometry of the protonation reaction has been calculated, showing that ACRYDyne is able to protonate twice both in solution and in solid polymer matrices, whereas P1000-ACRID only protonates once. The sensing sensitivity of the compounds is consistent with this. The antimicrobial activity of the hyperbranched polymer has been tested against five bacteria (Gram positive and Gram negative) and two yeasts, showing high antimicrobial activity. The biocompatibility of low- and high-molecular weight compounds has been studied towards two mammalian cell lines (C2C12 and Swiss3T3), and the hyperbranched polymer shows higher biocompatibility than its low-molecular weight reference compound. P1000-ACRID allows enough cellular viability when used in its biofunctional concentration range.