Studies On Coumarin Containing Organic-inorganic Composite Nano-probes And Their Application In Fe³⁺ Sensing

Metal elements are ubiquitous in our daily life,and are widely used due to their different forms of existence.All life forms have an absolute need for metal ions,because metal ions play a vital role in life activities such as osmotic regulation,enzyme catalysis,metabolism generation and signal transmission.Iron is an important component of hemoglobin,heme,a variety of enzymes and DNA,RNA,is necessary for normal physiological activities in the living body trace elements.Abnormal iron concentration can cause the disorder of normal physiological function and serious diseases,such as diabetes,iron deficiency anemia,low immunity,cancer and so on.Therefore,the detection of iron ions and other metal ions at the cellular level is of great significance for the monitoring of life activities and the diagnosis of disease.Electrochemical methods such as atomic absorption spectrometry(AAS)and inductively coupled plasma mass spectrometry(ICP-MS)have been used to detect iron ions.Although these detection methods have high sensitivity.However,the equipment of these detection methods is relatively expensive,the sample processing is more complicated,and the requirements of professional personnel for operation and analysis are required,which makes the Fe³⁺ion detection very difficult.It is particularly important to develop a chemical sensor that can detect iron ion efficiently,accurately,conveniently,rapidly and specifically.In recent years,fluorescent chemical sensors have attracted extensive attention in the field of biological detection due to their advantages of rapid,high sensitivity,simple operation and portability.Fluorescence probe materials based on coumarin organic small molecules have become a research hotspot due to their surface modification of ligands easily,their functional groups can participate in ion coordination,high selectivity ion detection,good photostability,low preparation cost and other advantages.In addition,coumarin material is mainly composed of hydrophobic thick ring structure,which makes the water solubility of this material is poor,which greatly limits the application of coumarin-based materials.Therefore,how to improve the water solubility of coumarin materials is the key problem to solve its application.In this paper,a new design concept of"internal hydrophobic,external hydrophilic"is put forward from the structural design of materials.The introduction of inorganic nanomaterials,through nucleophilic substitution reaction,with the effect of bonding coumarin hydrophobic groups toward the inside of the base materials and nanometer materials,hydrophilic group(ion trap group)toward the outside,the hydrophilic group can greatly extend in the solvent,through the molecule structure design can greatly improve water soluble materials,thus improve the ability of detecting probe material,makes the composite nano probe of the detection limit of 440 pM,actual detection range can reach 1 nM to 100 mM.At the same time,the composite material has good stability and selectivity in the detection of iron ion.Our synthetic materials can achieve cellular level iron detection and water-based ink anti-counterfeiting applications.The design of composite materials is of great significance for controlling the water solubility of amphiphilic organic small molecules and improving the sensing performance of metal ions.This material design has general implications for improving the properties of other organic molecules.