Cell encapsulation modes in a flow-focusing microchannel: effects of shell fluid viscosity

Abstract

Flow-focusing microencapsulation is an important process to protect the cells in biomedical applications. This article characterizes different cell encapsulation modes and presents the droplet volume distribution, frequency of encapsulation and cell population in terms of inner and outer fluid capillary ratios and viscosity of the shell fluid. The desired mode of at least one cell in a droplet is determined for different capillary number ranges and each viscosity ratios. The droplet volume and frequency of droplet generation are normalized for a combined non-dimensional parameter to classify different patterns of compound droplet formation which helps us to improve single-cell encapsulation process. With increase in orifice radius, the droplet volume increases, and the success rate of cell encapsulation increases. Above a critical radius, the encapsulation mode transitions from one cell to multiple cells captured inside the droplet.