PARTICLE ENCAPSULATION AND DETECTION BASED ON NON-NEWTONIAN MICRODROPLETS

Microfluidic droplet encapsulation technology can encapsulate single particle or multiple particles into microscale droplets. It has important biomedical applications such as cell culture, controlled drug release, and trace component analysis, and most of these practical applications involve complex non-Newtonian fluids with multiple phases. At present, it is still difficult to prepare non-Newtonian microdroplets with uniform size and achieve high-efficiency single particle encapsulation with these non-Newtonian microdroplets. In order to address this problem, we first conducted the experiments of non-Newtonian droplet generation and particle encapsulation based on flow-focusing microchannel and polymer solution, and systematically explored the effects of different non-Newtonian properties on droplet generation modes. It was pointed out that the polymer solutions with both shear thinning and elastic effects can realize stable generation of highly monodisperse droplets in jetting mode. On this basis, we combined this stable generation of highly monodisperse droplets in jetting mode with the inertia-viscoelastic particle sorting, and achieved high-efficiency single-particle encapsulation that overcomes the Poisson limitation of single particle encapsulation using traditional methods. Finally, we constructed an automatic detection model of particle encapsulation rate to achieve high-precision detection of the encapsulated particles in both single droplet and multi-droplet scenarios. To sum up, the research results of this paper not only expand the understanding of the basic theory of droplet microfluidic technology to a certain extent, but also fully verify the feasibility and superiority of the strategy of stable generation of non-Newtonian droplet in jetting mode for single-particle encapsulation, which can provide certain reference for optimizing the particle encapsulation technology based on non-Newtonian microdroplet and developing the corresponding integrated device.