Two dimensional alkaline earth metal sensors (2D-AEMS) of fluorescent strontium sulfide nanosheets for neurotransmitter drug detection via photo induced electron transfer (PIET)

Abstract

A new sensing platform has been introduced that provides a powerful solution for fluorescence-based biosensors using photoluminescent nanosheets (NS) using the novel two dimensional alkaline earth metal sensors (2D-AEMS). We have synthesized two-dimensional (2D) fluorescent strontium sulfide (SrS) NS using deep eutectic solvent (DES) as green solvent media by a hydrothermal method. The resulting product of 2D SrS NS to enhance the fluorescence intensity was achieved successfully followed by probe ultrasonication. The optical properties of SrS NS were studied by UV–visible and photoluminescence (PL) spectroscopy. The 2D SrS NS showed a blueish-green fluorescence optimized at λex320 nm/λem390 nm and a quantum yield of 38.6% was calculated. Under optimal conditions, the fluorescent SrS NS effectively detected noradrenaline (NA) by PIET-based fluorescence quenching and wavelength shifts were observed. Our proposed 2D-AEMS of 2D SrS NS fluorescence intensity was quenched in a wide linear range from 1 to 300 µM, with a limit of detection (LOD = 3*3SD/S) of 0.047 µM. The 2D-AEMS (fluorescent SrS NS) was applied to the determination of NA in human urine samples, with good recovery ranging from 98.7-100.08%. Also, the SrS NS fluorescence quenching mechanism in the detection of NA was investigated by zeta potential analysis, UV analysis, and dynamic light scattering (DLS). Our proposed 2D SrS NS fluorescence nanomaterials stand as an innovative platform for generating fluorescence sensors, with extensive potential applications in medical, biological, and life science fields, designed to replace traditional dye fluorescence in the near future.