A new phosphonate based Mn-MOF in recognising arginine over lysine in aqueous medium and other bio-fluids with “Sepsis” disease remediation

Selective detection of a particular amino acid in aqueous medium by using suitable solid state fluorescence sensor can offer a reliable diagnostic tool in biomedical research. Herein, we report a tetratopic phosphonate ligand (H8L) based MnII-MOF (H8L-Mn-MOF) [a = 28.211(8) Å, b = 12.265(3) Å, c = 10.535(3) Å, α = 90°, β = 99.295° (14), γ = 90° and CCDC no. −1922966] for selective recognition of L-arginine (Arg) over L-lysine (Lys) and other amino acids with detection limit of 7.1 ppm. Primarily the MOF remains in fluorescent quenched state in aqueous medium due to the presence of paramagnetic metal centres (MnII). However, upon interaction with electron rich amino acid (Arg), the MOF showed selective "Turn-On" behaviour, which was also supported from the DFT studies. In addition, the MOF material showed equal responsive behaviour in different bio-fluids such as fatal bovine serum and human urine suggesting its bio-applicability. Thus, the detection of this biomarker (L-Arg) from serum and human urine would help immensely towards preparing a paediatric reference range for clinical use. As an artefact, the patients with "Sepsis" disease will be detected with an ease using this tetraphosphonate based Mn-MOF.