A two-dimensional luminescent HOF containing an interpenetrating network structure with dual function: highly sensitive detection of methotrexate and multi-level information encryption

Abstract

In recent years, hydrogen-bonded organic frameworks (HOFs) have been used in fluorescence sensing and anti-counterfeiting applications because of their mild preparation conditions, excellent optical properties and biocompatibility, but dual-functional HOFs based on the same response mechanism have rarely been reported. Methotrexate (MTX) is a broad-spectrum anti-tumor drug. However, as the therapeutic window for MTX is narrow in the actual treatment process, it is particularly critical to monitor therapeutic drug concentrations in the human body to ensure accurate dosing. This paper reports a luminescent HOF with imidazole groups containing a two-dimensional interpenetrating structural network. It has favorable water stability and therefore holds promise as a fluorescent probe for the detection of methotrexate levels in humans. HOF–TIA prepared by a simple solvent volatilization method enables rapid and highly sensitive detection of MTX. The detection limit of MTX was 0.022 μM in aqueous solution and 0.061 μM in serum. The detection mechanisms of HOF–TIA toward MTX and adenosine monophosphate (AMP) were investigated and the color change phenomenon of HOF–TIA on encountering MTX and AMP was applied to the multi-level encryption of information. This study has not only produced a new HOF containing imidazole groups but also provided a typical example of a dual-function optical platform synchronously applied for fluorescence sensing and anti-counterfeiting.