Cheap microfluidic device for transmitting liquid flow by utilization of interface characteristics and for syphilis diagnosis

Abstract

The invention relates to a low-cost microfluidic device for syphilis diagnosis, which uses interface characteristics to transmit liquid flow, and belongs to the field of analysis and testing. There are some difficulties in making the substrate of the microfluidic chip for syphilis diagnosis with cheap and easy-to-process polydimethylsiloxane (PDMS); the surface of the PDMS material is strongly hydrophobic, and targeted surface modification or surface modification , its effect is difficult to last, this case aims to solve this series of related problems. The main point of this case is that the substrate is selected with PDMS with an original ecological surface, and a micro-ultrasonic transducer is attached to the position adjacent to the sample liquid flow terminal of the microfluidic chip to reduce the interfacial tension with ultrasonic waves, and at the same time use PDMS The strong absorption ability of ultrasonic waves achieves the rapid decrease of ultrasonic intensity in a short distance, and thus forms a difference in interfacial tension at both ends of the chip. The difference in interfacial tension causes a pressure difference at the two ends, and the pressure difference drives the sample liquid. Flow flows along the capillary channel towards the terminal.

Description

technical field [0001] The invention relates to a low-cost microfluidic device for syphilis diagnosis, which uses interface characteristics to transmit liquid flow, and belongs to the field of analysis and testing. Background technique [0002] For the technical background of multi-channel microfluidic syphilis diagnosis, please refer to CN 200910160439.X and other invention patent applications. [0003] As far as the overall overview of microfluidic technology itself is concerned, you can refer to the monograph "Illustrated Microfluidic Chip Laboratory" published by the famous microfluidic expert Mr. Lin Bingcheng not long ago, which has been published by Science Press. The past, present, and future prospects of microfluidic technology, etc., have detailed and long-form discussions that go deep into specific details. [0004] So, let's talk about the key issues of this case. [0005] The basic structure of a microfluidic chip includes a substrate etched with tiny liquid f...

AI Technical Summary

Problems solved by technology

[0007] But it's not that simple

[0008] First, this polydimethylsiloxane material, the material referred to by the acronym PDMS, is itself a strongly hydrophobic material. Microchannels are built on this material. If the microchannels are not targeted The modification operation of the surface of the channel, then, after the overall assembly is completed, that is, after the cover is covered, because the inner surface of the micro channel in the structure occupies most of the inner surface of the liquid flow channel, then the PDMS micro channel The strong hydrophobic characteristic of the inner surface of the channel is the decisive factor, which will make it very difficult for the polar liquid flow similar to the aqueous solution to pass through, and its flow resistance is so large that even ordinary micropumps are difficult to push. Of course, If the cover sheet also chooses to use the PDMS material, then the problem is basically the same, with little difference; therefore, in the prior art, it is necessary to modify and modify the inner surface of the microchannel on the PDMS material; then , is this modification operation for the inner surface of the PDMS microchannel very troublesome? That's not the problem. What constitutes a serious technical problem is another problem: the PDMS polymer molecules in the bulk phase of the PDMS material substrate have the characteristics of automatic diffusion and migration to the surface. The characteristics of polymer molecules diffusing and migrating to the surface automatically will make the modified state of the inner surface of the microchannel modified by the surface modification unable to maintain for a long enough time, and the microgroove after surface modification The maintenance time of the inner surface state of the channel is roughly only enough to complete the time required for the internal test experiment in the laboratory; in other words, the inner surface of the PDMS microchannel after surface modification or surface modification is formed after modification The surface state of the surface does not last long, but quickly tends to or changes back to the surface state before the surface modification, and returns to the original strongly hydrophobic surface state in a relatively short period of time. Then, just imagine, Can such microfluidic chips be produced in large quantities, stored in large quantities, and widely promoted? The answer is obvious, that is, impossible

This problem has also existed for many years, and so far, it has not been properly solved

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