Microfluidics allows for precise manipulation of small volumes of analytical solutions in diverse applications, including disease diagnostics, drug efficacy testing, chemical analysis, and water quality monitoring. Among these diverse applications, one of the most critical aspects is the precise and programmable control of flow within microfluidic control devices. However, microfluidic experiments that employ pressure control via a gas tank may encounter restricted mobility. To address these challenges, we developed an air pump feedback control system utilizing artificial intelligence image analysis and devised a method to enhance portability. In this paper, we utilized a commercially available portable pump to achieve the desired pressure and subsequently cease operation. In addressing the challenge of sustaining prolonged pressure, we implemented a strategy wherein the dimensions of the pressure vessel were modified, accompanied by iterative pump activations, thereby ensuring the sustained maintenance of pressure over time. The evaluation of the flow controller developed in this study involves conducting a comparative flow analysis with established pneumatic flow controllers. Furthermore, we employed artificial intelligence image analysis methods to automate the operation of iterative pumps. In conclusion, we anticipate that the developed portable microfluidic control device will lead to innovative advancements in modern technology and healthcare through its potential applications.

Advances in cell culture technology have improved the understanding of the physiological principles of cells. Recently, the development of microfluidic chips has made it possible to observe single cells in a massively parallelized and accurate manner. However, in order to maximize the availability of the microfluidic cell chip, it is essential to use an incubator that can isolate the cell culture chip from the outside while minimizing contamination and maintaining the temperature and humidity required for cell culture for a long time period. Here, we developed a thermo-hygrostat incubator consisting of an Arduino-based feedback control module for controlling a temperature and humidity complex sensor, a humidifier, and a heater. The temperature and humidity of the incubator could be actively changed according to the needs and application by simple editing control variables of Arduino coding. To demonstrate the efficiency of the device, we conducted an experiment comparing the growth of bacterial cells and obtained optimal conditions necessary for culture. In conclusion, it is expected that the newly developed thermo-hygrostat incubator can be used for a variety of purposes that require active control of temperature and humidity, as well as for long-term cultivation of bacterial cells inside a microfluidic chip.

A microfluidics chip is a miniature analytical system that injects a small amount of reagent into microchannels formed in the chip. It controls fluid flow to perform pretreatment, detection, reaction, mixing, separation, and analysis in parallel. In this study, polygonal microchannel structures were fabricated using a microstereolithography 3D printer based on an LCoS microdisplay projector. In the experiment, the width of the microchannel structure was changed from 50 ㎛ to 500 ㎛, and the output and width of the structure were measured. Inspection of the shape of the resulting microchannel structure showed that the tip of the structure was elliptical instead of the expected rectangular shape, and the fabrication width error increased as the channel width decreased to 200 ㎛ or less. Nevertheless, it was possible to fabricate microfluidics chip structures with widths less than 100 ㎛. The results of this study demonstrate the applicability of an LCoS microdisplay project-based 3D printer for the fabrication of microfluidic channel structures.

In this paper, theoretical and experimental studies were conducted on the cooling performance of a microchannel heat dissipation device with a manifold layer added. By adding 500 μm wide microchannels and manifold flow fields, the rheological properties of the cooling fluid were enhanced to improve the heat transfer performance. The size of the microchannel used for cooling was 40 × 40 × 5 mm, and was evaluated under a heat flux of 12.5-43.75 W/㎠ and a flow rate of 0.3-1.1 L /min conditions. As a result of the experiment, in the case of a microchannel heat sink of 500 μm compared to the existing heat sink, cooling was successfully performed under a heat flux condition of about four times