Copper Selenide Nano-plasmonic Light Scattering Spectroprobes And Their Applications In Heparin And Mercury Ions Detection

In recent years,probe spectrometry is a major research field in the field of analytical chemistry.According to the composition,shape and property of probes,there are many types of spectroprobes.Recently,research on semiconductor nano-spectroprobes such as quantum dots and carbon dots has achieved brilliant achievements,and has been widely used in biosensors and devices,biomedical imaging and other fields.Chalcogenide copper compounds(Cu_2-xE,E=S,Se,Te,0≤x≤1),as a new type of p-type semiconductor nanomaterials,due to their low price,low toxicity,good biocompatibility and specific optoelectronic properties,and have been widely used in photothermal therapy,analytical sensing and biological imaging.Non-stoichiometric copper selenide nanoparticles(Cu_2-xSe NPs),as one of the most important representatives of chalcogenide copper compounds,due to its unique highly copper defeciency structure,which lead to strong localized surface plasmon resonance（LSPR）property in the near-infrared region（NIR）.Although many properties of Cu_2-xSe NPs have been fully studied and widely used in many fields,there are still many potentials that have not been exploited,such as the study and the application of their light scattering properties are not sufficient.In particular,there are problems such as imperfection,inadequacy and unclear mechanism about its plasmonic light scattering properties.Therefore,developing Cu_2-xSe NPs as a new type of plasmonic light scattering spectroprobe and expanding its applications in the field of light scattering analysis are of great significance in order to study its scattering properties.In view of this,based on the plasmonic light scattering properties of Cu_2-xSe NPs,we established the method for the detection of heparin and mercury ions.The specific research content includes the following two aspects:（1）Cu2-_xSe NPs with plasmonic light scattering properties and the plasmonic light scattering spectroscopy of heparin.We used cetyltrimethylammonium bromide（CTAB）-coated Cu_2-xSe NPs as light scattering spectroprobes,which aggregated through the electrostatic interaction with heparin（Hep）and thus caused the resonance light scattering（RLS）signals of the system is significantly enhanced.Under the optimal reaction conditions,the increased RLS intensity is linearly correlated with the concentrations of Hep in the range of 0.01-0.60μg mL^-1（R²=0.999）,with a low detection limit（LOD）of 4.0 ng mL^-1（3σ）.This method offered a simple,sensitive and selective strategy for Hep sensing,which was successfully applied to quantify Hep in the heparin sodium injection.（2）Cu2_-xSe NPs with plasmonic dark-field light scattering properties and the dark-field light scattering imaging analysis of mercury ions.We used poly（allylamine hydrochloride）（PAH）-templated Cu_2-xSe NPs as light scattering spectroprobes,based on its plasmonic light scattering properties,we established a highly sensitive method for the detection of Hg²⁺.Due to the extremely high affinity between Hg²⁺and Se^2-,the added Hg²⁺can react with Cu_2-xSe NPs and exchange their Cu⁺/Cu²⁺,thereby forming a HgSe layer around the host nanoparticles.Therefore,the scattering light of Cu_2-xSe NPs significantly changed,the dark-field images changed from blue to cyan,and the scattering intensity enhanced.The relationship between Hg²⁺concentration and the increased intensity ratio can be used for analyzing Hg²⁺concentration,with a detection range of10-300 nM（R²=0.993）and the LOD is 1.07 nM.Due to good analytical performance,the proposed strategy based on Cu_2-xSe NPs has potential applications in the detection of trace Hg²⁺in actual water samples.In summary,this work uses the plasmonic light scattering properties of Cu_2-xSe NPs to construct corresponding plasmonic light scattering spectroprobes for plasmonic light scattering measurement of Hep in heparin sodium injection and for dark-field light scattering imaging based on Hg²⁺,which enriched the theory and application of light scattering spectroprobes.