Preparation Of Polymer Fluorescence Probe Based On Microfluidic

Polymer fluorescent probe has the characteristics of small particle size,high brightness,fast radiation transition rate,strong light stability and good biocompatibility.It has a wide range of applications in many fields,such as fluorescence imaging,biosensing,drug delivery,and disease diagnosis and treatment.The microreactor with small size facilitates to improve controllability for the experiment and provide a uniform environment for the reaction.The utilization of microreactor to prepare micro/nano materials has attracted great attentions recently.In this paper,the polymer fluorescent probe head been prepared by using the re-precipitation method in the microreactor.The particle size of the polymer fluorescent probe was regulate effectively in the microreactor.Firstly,the preparation of coaxial microchannel reactors made of capillary glass tubes were studied.The coaxial microchannel reactors with different sizes were prepared.Internal shrinkage sizes were 12 ?m,29 ?m and 42 ?m,respectively.The visual area,the coaxiality and the hydrophobicity of the reactor were optimized.The complete micro reactor preparation process was explored to solve the clogging and leakage problem.The flow pattern and diffusion state of polymer solution and deionized water in micro reactor were investigated.It was found that the diameter of the annular flow decreases as the water flow rate increasing when the flow rate of the polymer solution is constant.In the latter part of the microchannel,the diffusion of annular flow is more obvious,and the boundary between the two components is gradually blurred.When flow rates of the two component increase with the same ratio,annular flow disappeared and turbulence flow appeared.Fluent software was used to simulate the flow properties for each experimental conditions.The flow state,concentration distribution and velocity distribution were obtained at different locations in the channel.At low flow rate,the radial diffusion distance of the tetrahydrofuran(THF)solution is long and the diffusion is more sufficient.At high flow rate,the radial diffusion distance of the solution is short and the diffusion is more rapid.The simulation demonstrated that the diffusion state is in good agreement with the experimental results.At the same time,the flow and diffusion properties under different experimental conditions were qualitatively analyzed.The effect of polymer fluorescent probe size was explored.In this study,the preparation experiments of polymer fluorescent probes with different reactant concentration,two component flow rate ratio and increasing flow rate were designed respectively.It was found that the flow rate had a great effect on the particle size.The particle size decreases with increasing Pe number and Re number.When the turbulence occurs,the particle size is greatly reduced to 69 nm,which is close to the particle size of the polymer fluorescent probe prepared by the conventional method.The hydrodynamic diameters distributions of polymer fluorescent probes were measured using dynamic light scattering(DLS)technique.The morphology of polymer fluorescent probe particles was characterized by transmission electron microscopy.Microfluidic methods to prepare polymer fluorescent probe provide the viable foundation for further research in the future.Combined with the experimental and simulation results,the particle size was dominated with the diffusion rate of tetrahydrofuran in water.