Tuning the structure and properties of MoS2-SrTiO3 nanocomposite and its enzyme mimic behavior for enhanced optical sensing and measurement of H2O2 in biological samples

Abstract

In the present study a quick sensing assay was introduced based on novel biomimetic oxidase like behavior of Molybdenum Sulfide and Strontium Titanate (MoS2-SrTiO3) nanocomposite for colorimetric detection of H2O2. In order to improve the adhesion nanocomposite was encapsulated into the gel and loaded on the surface of filter paper. The synergistic effect of MoS2 and SrTiO3 on sensing exhibited the intrinsic peroxidase-like activity by catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) as substrate and as a result an improved naked eye response was observed. This enhanced response was well supported by characterizations techniques like FT-IR, SEM, XRD and Raman spectroscopy. For better sensitivity and selectivity, the following conditions like gel concentration (0.3 g/6mL) at room temperature, incubation time (30 min) and concentration of nanocomposite (2 mg/mL) were optimized. A better sensitivity was obtained with a lower limit of detection (LOD) of 0.08 µM in a relatively wide range of 0.1 µM to 5 µM and high correlation coefficient (R2) of 0.978. The ability of the sensor in real samples like milk and tap water was assessed with good recovery values ranging from 91 − 98 % in the presence of interfering compounds. This colorimetric detection using filter paper modified with enzyme mimetic nanocomposites is a step forward towards the point of care devices for onsite detection and monitoring of the dieases which was otherwise quite difficult and expensive.