Synthesis And Application Of Green Low-toxic Fluorescent Nanomaterials

Nanometer material,also known as the ultrafine particles,refers to the particles whose size are between 1 and 100 nm.It has surface effect,small size effect,macroscopic quantum tunnel effect and many other characteristics,which is widely used in the performance testing technique and scanning probe technology.Besides,as a kind of quasi-zero-dimensional semiconductor nanocrystals,quantum dot has excellent photoelectric properties.Some features of it are as follows:having high quantum yield fluorescence,high chemical stability and light stability,wide-chromatogy of excitation,narrow-emission,high-intensity and bio-compatibility.Therefore,it is recognized to be an emerging ideal nano fluorescent probe,and is in a hot period of research and development.Alkaline phospholipase(ALP)plays an important role in the normal growth of organisms.Scientific research has shown that the level of its content in the human body will seriously affects people’s health.Once the indicator is abnormal,it will lead to health problems such as nephritis,rickets and anemia.There has been some traditional detection method of ALP,such as electrochemical method,chemiluminescence,colorimetry,chromatography and spectrophotometry,etc.However,these methods not only need complex and expensive experiment instrument but also need more steps that are tedious and test time,which cannot meet the requirements of environmental protection and rapid detection.In recent years,fluorescence detection gradually replaces the traditional detection method,using the fluorescent probes such as CdS and CdTe.Although these materials have shown very good detection performance,they have a certain toxicity,making them restricted in the application of clinical or biological system.Therefore,further exploring and developing a more environmental and low-toxic quantum dot prober is of great practical significance and research value in promoting the development of material science and clinical medicine.This paper,aiming to prepare a green and low-toxic fluorescent nanomaterial,taking the quantum dots biological probe with good biocompatibility and high performance as the theme,has successfully prepared silicon quantum dots and carbon quantum dot.The study also used its fluorescence quenching effect to explore its application in quantitative detection of biological enzyme and adopted molecular template imprinting technology to prepare a kind of fluorescent composite material with better dispersion through the method of reverse micelle.This material’s size and spherical morphology is easier to control.Meanwhile,doing quantitative test of material for enzymatic reaction can expand the range of detection and the idea of application.The main research contents are as follows:(1)Preparation of silicon quantum dot and its composite materials;Feasibility study on ALP detection:This part introduced a new method of synthesizing silicon quantum dots.A series of representations and tests are given to prove that it can be well applied to the rapid detection of ALP.The experiment used sodium citrate and acrylic acid as basic reagents and used 3-aminopropyltriethyloxy silane(APS)as silicon source,which successfully synthesized the hydrophilic silicon quantum dots through one-step hydrothermal route.At the same time,It regulated the fluorescent color by adjusting the amount of acrylic acid and prepared silicon quantum dots who can launch two fluorescent colors,blue and green.In addition,in the alkaline buffer,based on the fluorescence quenching effects on ALP enzymatic reaction of silicon quantum dots,the fluorescence intensity of silicon quantum dots and the content of ALP show good linear rule in a certain range.The detection limit ranges from 2 U/L to 7500 U/L and the limit of detection is 1 U/L.Meanwhile,when the excitation wavelength is fixed to 350 nm,the fluorescence color of the solution reaction system will gradually change with the increasing content of ALP.And the visual inspection of ALP can be realized initially.(2)Preparation of and its composite materials;Feasibility study on ALP detection:Based on the successful preparation of carbon quantum dot who can launch blue fluorescence,this experiment used ’molecular template imprinting technology’ prepare the composite material CDs@ 4-NP @ SiO2 with high selectivity and density through the surface functionalization method.It solved the problem like that carbon quantum dot’s size is too small to be controlled and the surface modification is difficult.Besides,the experiment also explored its feasibility as a biosensor on fast testing of ALP content:on the best synthesing and testing conditions,the content of ALP ranging from 100 U/L to 2000 U/L and the fluorescence intensity of the composite material CDs @ 4-NP @ SiO2 have linear relationship.The linear equation is y=-1.08+333.5x.Linear correlation R2 is 0.996’ and the limit of detection is 0.8 U/L.