Design and Modeling of a Microfluidic Coral Polyps Culture Chip with Concentration and Temperature Gradients

Abstract

Traditional methods of cultivating polyps are costly and time-consuming. Microfluidic chip technology makes it possible to study coral polyps at the single-cell level, but most chips can only be analyzed for a single environmental variable. In this work, we addressed these issues by designing a microfluidic coral polyp culture chip with a multi-physical field for multivariable analyses and verifying the feasibility of the chip through numerical simulation. This chip used multiple serpentine structures to generate the concentration gradient and used a circuit to form the Joule effect for the temperature gradient. It could generate different temperature gradients at different voltages for studying the growth of polyps in different solutes or at different temperatures. The simulation of flow field and temperature showed that the solute and heat could be transferred evenly and efficiently in the chambers, and that the temperature of the chamber remained unchanged after 24 h of continuous heating. The thermal expansion of the microfluidic chip was low at the optimal culture temperature of coral polyps, which proves the feasibility of the use of the multivariable microfluidic model for polyp culture and provides a theoretical basis for the actual chip processing.

Keywords: concentration gradient; coral polyps; microfluidic chip; multivariable; numerical simulation; temperature gradient.

Figure 1

Coral and coral polyps. (a) Coral is composed of coral reefs, coral polyps and symbiosis microorganisms. (scale bar = 1 cm). (b) Polyps and symbiotic microorganisms; the yellow dots refer to Symbiodinium (scale bar = 1 mm).

Figure 2

The structure diagram of the microfluidic polyp culture chip.

Figure 3

Flow field distribution diagram in the microchannel. (a) Concentration distribution map in microchannel under steady state. The values of the concentrations are shown in the legend on the right. (b) Streamline distribution of the flow field in a culture chamber. The values of the flow rate are shown in the legend on the right, and the shear rates are represented in terms of the thickness of the flow lines.

Figure 4

Temperature profiles of the coral polyp culture chip. (a) The average temperature of polyp culture chambers under different potentials. (b) Temperature variation over time within the coral polyp culture chambers. (c) Temperature profile of polyp culture chip at 3 V voltage under steady state. The values of the temperature are shown in the legend on the right.

Figure 5

Thermal stress on microfluidic chips. (a) Von Mises effective stress caused by heat. The values of von Mises effective stress are shown in the legend on the right. (b) Displacement caused by heat. The values of displacement are shown in the legend on the right.