The Preparation Of Novel Fluorescent Silicon Nanoparticles And Their Applications In The Detection Of Drugs And Heavy Metal Ions

Fluorescent silicon nanoparticles?Silicon nanoparticles,SiNPs?,as a new type of fluorescent nanomaterials,have unique photoelectric properties.Compared with organic fluorescent molecules and quantum dots,it has the advantages of good biocompatibility,low toxicity,and strong resistance to photobleaching.It has been widely used in cell imaging,analytical testing,and medicine.However,the reported SiNPs have the problems of single fluorescence emission wavelength,complicated synthesis process of water-soluble SiNPs or multiple emission wavelengths located in the short-wave region,which cannot meet the needs of analysis and detection.Therefore,it is of great research value to develop and easily prepare SiNPs with dual emission or longer emission wavelength,and successfully apply them to drug analysis and detection of heavy metal ions.Based on this,this degree research paper mainly carried out the following work:?1?A brief introduction to the research progress of SiNPs in recent years is summarized,and the preparation,properties and applications of SiNPs are introduced.?2?The preparation of novel fluorescent silicon nanoparticles and the applications of ratio fluorescence system with Eu³⁺to detect tetracyclinesTetracycline?Tetracyclines,TCs?is a broad-spectrum antibiotic that is widely used to treat bacterial infections in animals and humans,but excessive use of tetracycline will cause antibiotic residues and bacterial resistance problems,so the use of simple and accurate methods for tetracycline determination seems very important.SiNPs-based ratiometric fluorescent sensor was designed to establish highly sensitive and selective method for detection of TCs.The sensor comprises the blue fluorescence SiNPs were prepared by hydrothermal method synthesis from?3-aminopropyl?-triethoxysilane and low-cost diethylene-triaminepent-acetic acid as the precursor,which serve as co-ligands for covalently bound with europium ions(Eu³⁺),and also the internal reference signal.In the presence of TCs,the luminescence intensity(?=616 nm,I₆₁₆)of Eu³⁺was significantly increased,while the luminescence intensity(?=450 nm,I₄₅₀)of SiNPs was reduced.The fluorescence intensity ratio of I₆₁₆/I₄₅₀50 of the sensor exhibits a sensitive linear range from 0.2-20?M with a detection limit of 3 nM for the detection of TCs.This method was successfully applied to determine the levels of TCs in nature river samples and milk samples with an excellent selectivity.?3?One-pot preparation of fluorescent silicon nanoparticles and its applications in detecting quercetinQuercetin?QCT?is a typical flavonol,which has a variety of biological activities.Therefore,the determination of QCT is very important in medicinal chemistry.The silicon nanoparticles?SiNPs?were synthesized through one-pot hydrothermal treatment of?3-aminopropyl?-triethoxysilane and sodium citrate.The obtained SiNPs exhibited fluorescent emission at 445 nm.Based on the internal filtering effect,the fluorescence of SiNPs was quenched by QCT,and a new fluorescence method for detecting the quercetin was developed.Under the optimal conditions,a linear range was obtained from 0.8-60?M with a limit of detection of 26 nM.The proposed fluorescent method was applied to the determination of QCT in the wine and drinks samples.Compared with the other detection methods,this method showed low detection limit and excellent selectivity,which has the potential applications in medicinal analysis chemistry.?4?The preparation of silicon nanoparticles emitting green fluorescence and its applications in highly selective detection of cobalt ionsCo²⁺as the main component of cyanocobalamin(vitamin B₁₂)and cobalt-containing coenzyme,involves many important reactions in the body,and may also affect the metabolism of certain trace elements.In addition,it is also used in many industrial fields.However,the widespread applications of cobalt has potential environmental problems.Therefore,it is very necessary to detect Co²⁺in the environment.In this work,?3-aminopropyl?-triethoxysilane and tyrosine were used as raw materials to prepare green light-emitting SiNPs by one-pot hydrothermal method and their morphology and properties were characterized.The prepared SiNPs had an excitation wavelength of 420 nm and an emission wavelength of 496 nm.When Co²⁺is added,the interaction with SiNPs causes the fluorescence intensity to decrease,and a new method for detecting Co²⁺is established.Under optimal conditions,the linear range of the method is 1-80?M,and the detection limit is 0.43?M.This method has been successfully applied to the determination of Co²⁺content in river and lake water.