Microfluidic chip device used for diagnosis of syphilis and using polydimethylsiloxane as substrate

Abstract

The invention relates to a microfluidic chip device used for diagnosis of syphilis and using polydimethylsiloxane as a substrate, belonging to the field of analytical testing. According to the invention, a plurality of problems are generated in manufacturing of a substrate of a microfluidic chip used for diagnosis of syphilis from cheap and easily-processed polydimethylsiloxane, i.e., PDMS. The main points of a technical scheme of the invention are as follows: the material of the substrate is PDMS with a nascent surface; the interiors of the channels of a chip are filled with doped micron-sized titanium dioxide particles, wherein the super-hydrophilic properties of the surface of the titanium dioxide particles can be induced out through preset visible-light irradiation; an assembly of gapsand channels among particles of the titanium dioxide particle filling material compensates and surpasses original highly-hydrophobic channels, so constant and super-hydrophilic modification effects are achieved; meanwhile, through a manner of coupling operation combining micropower ultrasonic-wave driving and micropump driving, a test specimen liquid flow is guided to flow towards the terminal direction along the channels of the chip.

Description

technical field [0001] The invention relates to a microfluidic chip device for syphilis diagnosis using polydimethylsiloxane as a substrate, and belongs to the field of analysis and testing. Background technique [0002] For the background of the multi-channel microfluidic syphilis diagnosis technology, please refer to the invention patent applications such as CN 200910160439.X. [0003] As far as the overall overview of microfluidic technology itself is concerned, you can refer to the monograph "Illustrated Microfluidic Chip Lab" 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 have been discussed in detail and in detail. [0004] So, let's talk about the key issues of this case. [0005] The basic structure of the microfluidic chip includes a substrate etched with channels and a cover sheet attached to it. The liquid flow channels on th...

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Problems solved by technology

[0007] But it's not that simple

[0008] First, this polydimethylsiloxane material, which is referred to by the acronym PDMS, is itself a strongly hydrophobic material, and channels are built on this material. modification operation, then, after the overall assembly is completed, that is, after the cover is covered, because the inner surface of the channel in the structure occupies most of the inner surface of the liquid flow channel, then the inner surface of the PDMS channel is The strong hydrophobicity is the decisive factor, it will make it very difficult for the polar liquid fine flow similar to the aqueous solution to pass through, and its flow resistance is so large that even the general micropump is difficult to push, of course, if the cover sheet is also If you choose to use the PDMS material, then the problems are basically the same, with minor differences; therefore, in the prior art, it is necessary to modify and modify the inner surface of the channel on the PDMS material; then, this is for the PDMS channel Is the modification operation of the inner surface of the channel 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 channel modified by the surface unable to maintain for a long enough time. The maintenance time of the internal surface state is roughly only enough to complete the time required for the internal test experiment in the laboratory; in other words, the surface state of the PDMS channel inner surface after surface modification or surface modification is formed after modification It cannot last for a long time, but it will automatically tend to or change back to the surface state before the surface modification, and return to the original strongly hydrophobic surface state in a short period of time. Then, just imagine, such a slight Can flow control chips be produced in large quantities, stored in large quantities, and widely promoted? The answer is obvious, that is, impossible

[0017] Third, as mentioned above, the inner surface of the PDMS channel is strongly hydrophobic, and targeted surface chemical modification or surface chemical modification is difficult to last. It is effective to use it within a short period of time; if the relatively short expiration date has passed and it is still used forcibly, since the surface state is already close to the hydrophobic state, there must be a relatively large liquid flow driven by the conventional micropump. In this way, the sample liquid can only be forced to flow in the target direction by increasing the pumping power and pumping pressure of the micropump. Sending pressure to pump the sample liquid flow will cause bubbling, puffing, twisting, and deformation of the channel at the sampling end of the substrate, including the area near the sampling end, and, under such high pressure conditions, in the The channel and its periphery at the injection end and its vicinity are also prone to peeling between the substrate and the cover slip. In this case, the sample solution will enter the gap between the substrate and the cover slip formed after the peeling. This actually leads to the damage of the microfluidic chip; of course, if the surface modification or surface modification is not in place, it will also lead to the above-mentioned situation within the short customary validity period; In the case of an external micropump for liquid flow drive, the above-mentioned problem always exists

As mentioned above, if no pre-operations such as surface modification or surface modification have been done at all, then the above-mentioned problem will be more serious, even if there is no channel bubbling at the injection end and its vicinity, Problems such as puffing, twisting, deformation, and peeling between the substrate and the cover sheet, etc., just because the flow resistance is too large, the use of a high-pressure micropump may not be able to drive the sample liquid flow toward the terminal.

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