Study On Particle Transport In Alveoli Based On Microfluidic Technology

With the economic development,the quality of the atmospheric environment is deteriorating.After the inhalable particles in the air enter the human body,they may deposit in the alveolar region and cause lung lesions such as emphysema,which may cause harm to human health.At the same time,inhalation therapy is becoming more and more widely used in clinical practice.How to develop inhalation therapy technology,improve efficacy and reduce side effects are still important issues.Therefore,the study of airflow characteristics in human alveolar areas and the deposition and transport mechanism of inhalable particles is of great significance not only for the study of the causes,treatment and prevention of pulmonary diseases,but also for the in-depth study of the transport of inhalable drug particles in the lungs.Due to the small size,large number and complex structure of human alveoli,it is difficult to establish a physical model of alveolar flow.At present,most of the studies on particulate matter in the respiratory system adopt numerical simulation method.While in most experiments,according to geometric similarity,enlarged alveolar experimental models are generally adopted for flow display and particle deposition experiments.In this paper,a microfluidic alveolar chip with the same size as the real human alveoli is designed to simulate the dynamic process of alveolar contraction and expansion caused by respiration on the chip.An in vitro simulation model of particulate matter in human alveoli was established and a particle tracer experiment platform was built.In this paper,the method of simulating the track of particles in air in alveoli with silver particles in solution was determined,and the track of particles was tracked and analyzed by software.This paper summarizes the movement rules of 0.5 micron particles in alveolar chip under the action of gravity and fluid at the same time,probes into the movement track of particles in different levels of alveoli and the influence factors of particle movement and deposition,and compares the difference of particle movement track in the case of gravity and no gravity.According to the trajectory data obtained from the experiment,it is found that the motion of particles is mainly influenced by the fluid drag force and its own gravity.The influence factors of particle velocity in different generation of alveoli were different.Multiple respiratory cycles and gravity promote the deposition of particles deep into the respiratory system.Gravity is a decisive factor in particle deposition.The experimental method established in this paper,the airflow movement characteristics in the alveolar area and the transport rules of fine particles will provide a basis for the study of drug delivery in the lung,and have certain guiding significance for the follow-up experimental research on the movement characteristics of particles in the alveolar area.