| In recent years,human’s growing concern about food safety has provided new opportunities and impetus for the development of food safety rapid detection technology.In the research of food safety rapid detection,the immunomagnetic bead separation technology has shown good application prospects in the preparation of food samples due to its high sensitivity and short processing time.In the immunomagnetic bead separation method,factors such as the binding rate of antigen and antibody,the degree of collection and dispersion of magnetic beads,etc.all affect the separation purity and recovery rate of the target analyte.in this paper,we have used the periodic horizontal excitation to drive the reaction cup sloshing to accelerate the combination of immunomagnetic magnetic beads and target analytes,and proposed A method for realizing rapid and uniforming dispersion of magnetic beads by using low liquid filling ratio fluid sloshing,and designed A fully-automated and high-recovery immunomagnetic bead separation system for food safety testing.The main contents of the paper include the following three aspects:1.First of all,we have proposed to use periodic horizontal excitation to drive the reaction cup sloshing to accelerate the combination of Immunomagnetic beads and target analytes.We have established the hydrodynamic model of fluid sloshing in the reaction cup induced by periodic horizontal excitation.Based on the finite element analysis method,we have studied the effects of horizontal excitation parameters and dynamic viscosity on fluid sloshing.The simulation results have shown that the horizontal excitation should be consistent with the direction of the fluid free sloshing acceleration,and the excitation work time should not exceed 1/4 fluid free sloshing period.The β-agonist(clenbuterol)rapid detection combined experiments confirmed that the adsorption reaction time of the Immunomagnetic beads and target analytes can be shortened by 25% in the increase of fluid sloshing compared with the static incubation state.2.Secondly,we have proposed a method for realizing rapid and uniforming dispersion of Immunomagnetic beads by sloshing with low liquid filling ratio fluid.Based on the finite element analysis method,we have studied the effects of liquid filling ratio on fluid sloshing.The simulation results have shown that the fluid sloshing of low liquid filling ratio can greatly improve the dispersion efficiency of Immunomagnetic beads compared with the full-cleaning-liquid volume(500 ul).For the magnetic bead which diameter is 1 um,the magnetic beads uniform dispersion time can be shortened to 11.5% of the time in fullcleaning-liquid status,only 2.5 s,there is no visible magnetic beads on the inner wall of the reaction cup.3.At last,we have used the Mechanical Sampling Arm,the incubation bed,the Immunomagnetic bead reagent cold storage and the above studies to build a fully-automatic immunomagnetic bead separation system successfully.Besides,we have verified the performance of the system by the β-agonist(clenbuterol)rapid detection combined test.95% spiked recovery of ractopamine in the sample has been achieved.The system is of great significance for improving the pre-treatment speed of samples,improving the status of food safety testing,and breaking the cost of transfer fluid style workstations. |
