Comprehensive Hydrodynamic Investigation of Zebrafish Tail Beats in a Microfluidic Device with a Shape Memory Alloy

Abstract

The zebrafish is acknowledged as a reliable species of choices for biomechanical-related investigations. The definite quantification of the hydrodynamic flow physics caused by behavioral patterns, particularly in the zebrafish tail beat, is critical for a comprehensive understanding of food toxicity in this species, and it can be further interpreted for possible human responses. The zebrafish's body size and swimming speed place it in the intermediate flow regime, where both viscous and inertial forces play significant roles in the fluid-structure interaction. This pilot work highlighted the design and development of a novel microfluidic device coupled with a shape memory alloy (SMA) actuator to immobilize the zebrafish within the observation region for hydrodynamic quantification of the tail-beating behavioral responses, which may be induced by the overdose of food additive exposure. This study significantly examined behavioral patterns of the zebrafish in early developmental stages, which, in turn, generated vortex circulation. The presented findings on the behavioral responses of the zebrafish through the hydrodynamic analysis provided a golden protocol to assess the zebrafish as an animal model for new drug discovery and development.

Keywords: hydrodynamics; microfluidics; shape memory alloy (SMA); tail beat; zebrafish.

Figure 1

The fabrication process of the microfluidic and shape memory alloy (SMA) device. (a) i–v illustrates the various fabrication processes involved in the making of the proposed microfluidic device. (b) i–v illustrates the series of fabrication processes involved in the fabrication of the SMA device. (c) Illustration of the fabricated microfluidic device with the SMA integrated together.

Figure 2

Illustration of the microfluidic device actuating operation using the SMA. (a) (i) and (b) (i) are the pictorial illustrations of the microfluidic device before and after the actuation process. (a) (ii) and (b) (ii) are the microphotographs captured before and after the actuation process.

Figure 3

(a) The microphotograph of the zebrafish (6 d.p.f.) fixed in the observation region for tail quantification time. (b–d) The hydrodynamic quantificational measures of the zebrafish tail beating. The vorticity field (color map) is overlapped with the velocity vector field (black arrows) generated during tail beatings of zebrafish larvae (6 d.p.f.). (e) Instantaneous circulation formation due to the hydrodynamic right and left tail beating of zebrafish larvae (4, 5, and 6 d.p.f.) with effective test samples in each experimental group (N = 10).

Figure 4

Effects of the cochineal red additive on tail-beating force of zebrafish larvae (4, 5, and 6 d.p.f.). Zebrafish larvae (5 and 6 d.p.f.) showed a transit change in the tail-beating force hydrodynamically with effective test samples in each experimental group. Significant differences between the control and the exposure groups are indicated by asterisks, (* p < 0.05) and (** p < 0.01) as compared with the control for 4, 5 d.p.f. (N = 10), and 6 d.p.f. (N = 30).