A fluorescent ESIPT-based benzimidazole platform for the ratiometric two-photon imaging of ONOO(-)in vitroandex vivo

Abstract

In this work, we have developed an ESIPT-based benzimidazole platform (MO-E1andMO-E2) for the two-photon cell imaging of ONOO(-)and a potential ONOO--activated theranostic scaffold (MO-E3). Each benzimidazole platform,MO-E1-3, were shown to rapidly detect ONOO(-)at micromolar concentrations (LoD = 0.28 mu M, 6.53 mu M and 0.81 mu M respectively). The potential theranosticMO-E3was shown to release the parent fluorophore and drug indomethacin in the presence of ONOO(-)but unfortunately did not perform wellin vitrodue to low solubility. Despite this, the parent scaffoldMO-E2demonstrated its effectiveness as a two-photon imaging tool for the ratiometric detection of endogenous ONOO(-)in RAW264.7 macrophages and rat hippocampus tissue. These results demonstrate the utility of this ESIPT benzimidazole-based platform for theranostic development and bioimaging applications.