Controlled-synthesis of alumina-graphene oxide nanocomposite coupled with DNA/ sulfide fluorophore for eco-friendly "Turn off/on" HS nanobiosensor.

Hydrogen sulfide (HS) is a toxic environmental pollutant and crucial gas-signaling agent of human physiology. There is an urgent need for developing a sensitive and selective detection approach for HS. Herein, a novel turn off/on response approach using γ-AlO nanorods anchored on the surface graphene oxide (GO) nanosheets and coupled with DNA/sulfide fluorophore (SF) for HS detection at room temperature was developed. The fluorescent fluorophore, DNA/SF, remains quenched on the super quencher γ-AlO-GO hybrid surface. In the existence of HS, DNA/SF fluorophore was detached from γ-AlO-GO hybrid surface because of the strong physical adsorption interaction between HS molecules and γ-AlO-GO surface. The recovered fluorescence intensity gave direct insight about HS concentration in the medium. The developed γ-AlO-GO/DNA/SF nanobiosensor shows high sensitivity with 75 to 2.5 μM linear detection range of HS, and a high binding constant of 9.8 × 10 M. The nanobiosensor is very selective toward HS in the presence of various interfering anions and thiols and used for HS detection in real water samples. γ-AlO-GO/DNA/SF nanobiosensor provides a cheap, simple, and highly selective HS detection method at room temperature.