In this work, we have developed an ESIPT-based benzimidazole platform (MO-E1 and MO-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 μM, 6.53 μM and 0.81 μM respectively). The potential theranostic MO-E3 was shown to release the parent fluorophore and drug indomethacin in the presence of ONOO- but unfortunately did not perform well in vitro due to low solubility. Despite this, the parent scaffold MO-E2 demonstrated 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.
Bibliographical noteFunding Information:
MLO, JEG, SDB and TDJ would like to thank the University of Bath for support. MLO and JEG thank the EPSRC for studentships. TDJ wishes to thank the Royal Society for a Wolfson Research Merit Award. H. M. K. acknowledges a grant from the National Leading Research Lab Program of the National Research Foundation of Korea (NRF), funded by the Korean government (2019R1A2B5B03100278). JY acknowledges a grant from the National Research Foundation of Korea (NRF) funded by the Korean government (MSIP) (No. 2012R1A3A2048814). NMR Characterisation facilities were provided through the Chemical Characterisation and Analysis Facility (CCAF) at the University of Bath (https://www.bath.ac.uk/ccaf). All data supporting this study are provided as ESI† accompanying this paper.
© The Royal Society of Chemistry.