Microfluidic device for sorting single cells of different sizes based on sliding principle

“3D printing of PDMS top and bottom layers of assembled microfluidic chips is frequently used in microfluidics to handle manipulation and control of submillimeter-scale fluid flow in tiny channels. The medical field has benefited from the development of numerous microfluidic devices to aid cell analysis.Annal Arumugam Arthanari Arumugam from the University of Saskatchewan published a graduate paper titled “Microfluidic device for potential applications based on sliding principle to help sort cells of different sizes,” according to Memes Consulting. Thesis, focusing on a novel microfluidic device design concept, says

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3D printing of PDMS top and bottom layers of assembled microfluidic chips is frequently used in microfluidics to handle manipulation and control of submillimeter-scale fluid flow in tiny channels. The medical field has benefited from the development of numerous microfluidic devices to aid cell analysis. Annal Arumugam Arthanari Arumugam from the University of Saskatchewan published a graduate paper titled “Microfluidic device for potential applications based on sliding principle to help sort cells of different sizes,” according to Memes Consulting. dissertation, focusing on a completely new microfluidic device design concept called the sliding principle.

In the paper, Arumugam said that while most microfluidic devices can capture, isolate, locate and sort individual cells, most can only be used for cells of the same size. Tunable microfluidic devices can be used to capture and sort individual cells with sizes ranging from 20 to 30 μm, but many applications require sizes ranging from 2 μm to 100 μm and beyond.

Experimental setup for testing channel spacing The paper statement states that “This paper begins with an analysis of different operating principles for trapping and sorting single-cell devices in an attempt to find a solution to the problem. As a result, this paper proposes a new principle for Single cells ranging in size from 2 μm to 100 μm are sorted by a principle known as the ‘sliding principle’. To verify the validity of this principle, the researchers designed a The hole device, which was designed and fabricated using soft lithography, and the mold in which it was fabricated using 3D printing. The researchers used a microscope (resolution: 1-3 μm) and a mobile stage (resolution: 1 μm) to conduct experiments , demonstrating that the device can be adapted to the size of micropore traps, ranging from 0-1000 μm and fully cover the desired size range of micropores (eg: 2-100 μm).

Based on the current literature on mechanical methods for capturing and sorting single cells of different sizes with one device, devices constructed based on the sliding principle are expected to be suitable for capturing and sorting single cells of different sizes. “The overall functional requirement (FR) of the device is to be able to capture cells of different sizes, from 2 μm to 100 μm, with a resolution of 2-5 μm, the sub-functional requirements include: * Forming sliding pairs so that the traps change with the sliding Size* capable of running a slip trap* pumping cellular fluid through the trap

Sliding principle of adjustable traps (a) the trap is a square with four sides that can slide; (b) microfluidic devices that touch cells by sliding one side to change the trap size must be made of biocompatible materials , the maximum stress in the cell should be less than 4.5 Pa and the sliding adjustment range is less than 1000 μm. Arumugam considered two design options for his slip catcher, but the first was unsuccessful because the contact surfaces of the two blocks were not smooth enough to slide smoothly between blocks and there was a potential for leaks. So he instead focused on the second design option.

Arumugam explained, “This design is divided into two layers (top and bottom), each layer has several micropores (however, only one micropore is designed in this paper, without loss of generality), and the micropore shape is Squares. Specifically, on the top layer, the square is a convex surface with protrusions, and the square on the bottom layer is concave. When the two layers are assembled together (the top layer is on top of the bottom layer), they form a system…”

Actuator rails, brackets, top block and bottom block of the top block, with an embedded layer made of PDMS (polydimethylsiloxane) constituting the actuation mechanism; a single axial stage with a moving resolution of about 3 um is made of 835 rigid Made of opaque white material to help drive the top block. Arumugam used Polyjet 3D printing technology to make molds for the PDMS parts.

While testing the design, the device was measured to see if it complied with “geometric and topological device design specifications,” and the researchers also measured sliding operations to “examine changes in micropores.” The measurements of the PDMS layer were satisfactory, showing that the sliding principle concept was indeed working, there was slight erosion on the sides of the PDMS layer, making the channel spacing less precise; the damage was caused by the sticky PDMS not peeling cleanly from the mold during curing .

The 3D printed mold and slide assembly for the PDMS layer, manufactured by the university’s engineering studio Arumugam added, “During the first few experimental attempts, the PDMS did not cure well, and the PDMS layer (injected part) stuck to the mold and did not cure. Damaged during peeling. To solve this problem, we pre-baked the 3D printed mold in an oven at 85°C for 4 hours before curing the PDMS layer. However, the problem did not go away completely. The problem would cause Inaccuracies in the dimensions of the injection molded parts (approximately 2um error) can also lead to surface damage. The resolution problem can be partly attributed to the 1mm channel size.

The channel size affects the focusing of the microscope, which in turn affects the number of pixels covered by the view, which ultimately affects the pixel resolution, especially as the pixel length becomes 8.547 um. Assuming a maximum channel size of 100 μm, the measurement resolution becomes 0.855 μm. The author also cites work that has helped advance microfluidic device technology, such as optimizing the fabrication of PDMS channels and further modifying his design.