Research Of Tough Hydrogel Marbles Based On Droplet Microfluidic Technology

Tough hydrogel marbles exhibit great potential in applications related to biosensors,drug delivery,tissue engineering.The microfluidic droplet technology has the unique advantages of low sample consumption,high flux,short analysis times and no cross contamination.This thesis explores the preparation of controllable and stable droplets based on microfluidic.Subsequently,tough hydrogel marbles are prepared based on microfluidic droplet technology and the mechanical properties systematically studied.The main research contents are as follows:Firstly,this thesis is devoted to the preparation of the stable droplet with controllable size based on microfluidic droplet technology.For this purpose,oil impregnated with PTFE particles(1 ?m)was used as the continuous phase while as the dispersed phase water was employed.The size and stability of the droplets were controlled by changing the type of oil,the amount of PTFE particles,and the flow ratio of continuous phase and the dispersed phase.The results illustrated that when FC-40 fluorinated liquid was used as the continuous phase,the mass fraction of PTFE particles in the fluorinated liquid was 0.75% while the flow ratio of continuous phase and the dispersed phase was 10:1,the prepared droplets were stable and uniform in size(about 400 ?m).The generated droplets based on microfluidic droplet technology feature the excellent stability,adjustable size and low toxicity,and could be used in crystallization culture of protein and cell.The second goal of the thesis is the generation of the tough hydrogel marbles based on the microfluidic droplet technology.Firstly,use the droplets generation device with PTFE pipe to assembly the prepare alginate-acrylamide hydrogel droplet with the irradiation of UV light(245 nm)and 80? for 2 h,and then the acrylamide crosslinked;Finally,soak the pre-crosslinked hydrogel droplet in the calcium ions solution and the ferric iron ions solution to generate tough hydrogel marble.In order to prevent pregel from cross-linking in advance,pregel mixture and pregel droplets were prepared in an ice bath,and stable pregel droplets with a diameter of 1000 ?m were obtained.In addition,the size of tough hydrogel marbles can be changed from 1000 ?m to 875 ?m by adjusting the immersion time of the pre-crosslinked hydrogel droplet in calcium ions solution.The method features simple equipment and simple operation,and could provide a new idea for the preparation of tough hydrogel marbles.In the end,the study on the elastic properties of tough hydrogel marbles.Explored the elastic properties of tough hydrogel marbles by observing the springback behavior with the tough hydrogel marble free falling from the height of 1 cm and impacting the hydrophobic base(contact Angle ?150°).The results revealed that the untreated tough hydrogel marbles(without calcium ion solution and ferric ion solution)showed only low elasticity,while the tough hydrogel marbles soaked with calcium ion solution and ferric ion solution could rebound eight times in a row.In addition,the concentration of calcium ion solution and soaking time had no obvious effect on the number of rebound times of the tough hydrogel marbles.The recovery coefficient(the square ratio of the rebound height)was between 0.7 and 0.9.Therefore,the tough hydrogel marbles soaked in calcium ion and ferric ion solution have good elastic properties and are expected to be used for the protection of protein crystals,mechanical equipment and human body impact protection.