a-microfluidic-system-for-modeling-endothelial-dysfunction-under

A Microfluidic System for Modeling Endothelial Dysfunction under Combined Physiological Pulsatile Shear Stress and Oscillatory Hyperglycemia

Endothelial dysfunction in diabetic vascular complications involves complex interactions between metabolic disturbances, specifically oscillatory glucose ...

Dalian University of Technology

In transfer printing, the loaded droplet on the probe has a significant influence on the dispensing resolution. A suitable loading approach for a high-viscous liquid is highly required. Herein, a novel electrostatic loading method is presented, in which the main aim is to control precisely the formation and breaking of a cone-shaped liquid bridge. An experimental device is developed. The influence of electrical and geometric parameters on the feature size of the liquid bridge is investigated in detail. In the formation of the liquid bridge, the increase of voltage or the decrease of the air gap can enhance the electric field intensity, thus reducing the formation period and increasing the initial cone tip diameter of the liquid cone. After the liquid bridge is formed, both the circuit current implying the liquid wetted area on the probe surface and the lifting velocity of the probe are utilized to further regulate the volume of the loaded droplet. Loaded droplets ranging from 60 to 600 pL are obtained via the method with a standard deviation of 4 to 30 pL. Moreover, a dot array is transferred with different loaded droplets. The minimum diameter of the printed dots is about 140 μm with a variation less than 5%. The advantages include the reduced risk of contamination, the droplet-size independent of the size of the probe, and the low cost of the device.

Loading a High-Viscous Droplet via the Cone-Shaped Liquid Bridge Induced by an Electrostatic Force.

The stretching breakup of a conical liquid bridge is the core process of micro-dispensing. To precisely control the droplet loading and improve the dispensing resolution, a detailed study of bridge breakup with a moving contact line is required. A conical liquid bridge is established by an electric field and stretching breakup is investigated here. The effect of contact line state is investigated by examining the pressure at the symmetry axis. Compared to the pinned case, the moving contact line causes a shift of the pressure maximum from the bridge neck to top, and it facilitates the evacuation of the bridge top. For the moving case, factors affecting the contact line motion are then considered. The results show that the increase of the stretching velocity  and the decrease of the initial top radius   accelerate the contact line motion. And the amount of contact line movement is basically constant. To analyze the influence of the moving contact line on bridge breakup, neck evolution is tracked under different . An increase of  decreases the breakup time and increases the breakup position. Based on the breakup position and the remnant radius, the influences of  and   on remnant volume   are examined. It is found that   decreases with an increase of  and increases with an increase of  . Accordingly, different sizes of remnant volume can be obtained by adjusting  and  . This is helpful for the optimization of liquid loading for transfer printing.

Stretching breakup of a conical liquid bridge with a moving contact line.

In the electroinduced formation of a highly viscous liquid bridge, improving the efficiency of formation is important for industrial applications. This paper presents the preregulation method of the polarization status to shorten the formation time of a liquid bridge. The hindering effect of high viscosity on the polarization of liquid suspensions was investigated. The formation time of the liquid bridge is shortened, and stability is improved by prepolarizing the initial liquid film, with a maximum reduction in the average and standard deviation of times by 12.65 and 2.52 s, respectively. These effects are confirmed at different viscosities and voltages. In addition, this method has no obvious influence on the shape of the liquid bridge. This study provides an approach to improve the electroinduced formation.

Article	Year
Loading a High-Viscous Droplet via the Cone-Shaped Liquid Bridge Induced by an Electrostatic Force. Langmuir : the ACS journal of surfaces and colloids\| PubMed ID: 33529533	2021
Stretching breakup of a conical liquid bridge with a moving contact line. RSC advances\| PubMed ID: 37143918	2023
Polarization Effect and Improvement of the Electroinduced Formation Efficiency of a Highly Viscous Liquid Bridge. Langmuir : the ACS journal of surfaces and colloids\| PubMed ID: 37812686	2023

Xiao-Yu Xu

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