ES2626263A1 - Reusable platform for assembling glass capillaries for micro fluids (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

The present invention is a reusable device serving as a platform for glass capillaries used in micro-fluids. The device comprises three parts: a platform, an injector, and a sealing system. The platform serves as a support and guide to the glass capillaries. In addition, this and the injector consist of an injection chamber that houses the glass capillary and receives the fluid injected from the outside through a needle inserted in the injector. Both injection chambers together with the glass capillary that comes out of them, are sealed by the sealing system, which comprises two rubber washers, each surrounding a chamber, whose pressure is adequate through the pressure adjustment system, a screw with a thumb nut. The device is easy to use, reusable and allows to work with high fluid flows. (Machine-translation by Google Translate, not legally binding)

Description

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DESCRIPTION

Reusable glass capillary assembly platform for micro fluids.

TECHNICAL SECTOR

The present invention relates to a reusable platform, used to create micro fluid circuits by assembling glass capillaries therein. This platform allows to assemble and disassemble the capillaries quickly and reproducibly. In addition, glass capillaries can be reused, since assembly and disassembly does not cause damage to the capillary. This platform also provides great chemical compatibility and efficient sealing of injection chambers within the usual range of fluid flows used in this technique.

BACKGROUND OF THE INVENTION

The technique called microfluids, from English "microfluidics", is a field that has expanded widely in recent years for different applications. It is a technique that makes use of devices with micro channels, well carved in some type of material, usually polydimethylsiloxane adhered by chemical interactions to a glass plate, or glass capillaries, usually borosilicate, attached to a glass slide, For a variety of applications.

In the case of micro channels carved into pieces of polydimethylsiloxane (Duffy, David C., et al. "Rapid prototyping of microfluidic systems in poly (dimethylsiloxane)." Analytical chemistry 70.23 (1998): 4974-4984.), The circuits are designed to pleasure, with different configurations depending on their application, which gives them great versatility. The channels communicate with the outside through holes drilled manually in the polydimethylsiloxane into which a needle is introduced through which the fluids are introduced. Its manufacture from a mother mask, which can be reused to produce multiple micro-channel systems in parallel, increases its production efficiency; although they must be manufactured in clean rooms, which greatly limits access to this technique. However, despite its relatively efficient manufacturing, this material has a very limited chemical compatibility and, with use, the circuits are damaged, probably releasing particles of the material to the fluids, and even being able to get blocked without repair, So the circuit must be discarded.

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This design finds its most fruitful application in systems where the fluid to be used is water or water-based buffer solution, as in the case of cell handling for a wide variety of applications, or in the classification of micro particles, whether cells or synthetic particles. However, although with a worse performance compared to the systems based on glass capillaries, it has been used for manipulation of fluids on a micrometric scale in order to mix miscible fluids or produce emulsions of immiscible fluids.

In the case of microfluidic systems that make use of glass capillaries (Herranz-Blanco, Barbara, et al. "Microfluidic assembly of multistage porous silicon-lipid vesicles for controlled drug release." Lab on a Chip 14.6 (2014): 1083-1086.), The capillaries are adhered to glass slides by means of a contact glue. Usually, there is a capillary attached to the glass plate in which one or more capillaries are inserted, one at each end of the capillary and / or concentrically one inside the other, with an outside diameter smaller than the inside diameter of the capillary in which they insert, so that concentric flows can be created flowing in the same direction; opposite flows, with opposite directions; or a combination of both. The entrances and exits of the capillaries are generally coupled to a syringe needle through a cavity that is manually carved therein, in turn adhered to the glass plate by contact glue. Thus, the entry and / or exit of each capillary is sealed and communicates with the outside through a needle through which the fluids are introduced.

Compared to the system described above, the fabrication of this device is very laborious and not always satisfactory, depending largely on the manual skills of the person who manufactures it, due to the possibility of blocking the entry of glass capillaries with the contact glue used to adhere and seal the components. In addition, if during use one of the capillaries is blocked or broken, the device cannot be repaired, and a completely new device must be manufactured. The advantage of this design is its great chemical compatibility, making it useful for applications where the use of organic solvents, acids or bases is necessary.

This design is used primarily for the manipulation of fluids on a micrometric scale in order to mix miscible fluids or produce emulsions of immiscible fluids. Specifically, through this technique, emulsions have occurred

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single, double, triple, etc., and multiple combinations of these. It has also been used for the technique called nanoprecipitation, in which two miscible fluids flow in the same direction, mixing and resulting in precipitation on a nanometric scale of chemical compounds, usually polymers.

EXPLANATION OF THE INVENTION

In order to make the manufacturing process of microfluidic devices much more efficient in terms of time and success rate, we propose our invention: a reusable microfluidic platform to be used with glass capillaries.

The device consists of a platform that holds the glass capillaries arranged in variable configurations according to the application, as explained in the previous section. The entrance hole of the capillaries is housed and sealed in the injection chamber of the platform, through which fluids can be introduced into the glass capillaries. In the same way the fluid can leave the capillary system from another injection chamber or directly through the orifice of the capillary.

The device can be manufactured in a single piece or in several modules, called a one piece platform and modular platform, respectively (figure 1). The materials used for the manufacture of the platform can be selected depending on the needs, normally defined by the chemical components that are intended to be used.

The device can be manufactured for use with several sizes of glass capillaries and also allows the assembly and disassembly of glass capillaries without damaging them, which allows the exclusive replacement of capillaries that have been blocked without the need to replace the entire system.

To facilitate the understanding of the system, below, the design of each module that makes up the modular platform for microfluids is detailed:

1. Lower platform: the platform is a solid base of variable size, depending on the needs. Platform surface

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It contains the injection component which in turn comprises an injection chamber, channels to accommodate the glass capillaries, as well as a circular channel surrounding the injection chamber to house the washers (Section 3). In addition, the platform provides support for the upper platform (Section 2).

The injection component may be carved on the surface of the platform or inserted into a cavity carved into the platform, called the insertion cavity of the injection component, as a carved cubic piece of a material other than that of the platform that ensures a High chemical compatibility of this element.

2. Upper platform: it is a mobile platform anchored to the lower platform that contains the injection component, which in turn comprises an injection chamber, channels to accommodate the glass capillaries, as well as a circular channel surrounding the injection chamber to housing the washers (Section 3) In addition, the injection chamber connects to the outside through a needle inserted through the platform and the injection component.

The injection component may be carved on the surface of the platform or inserted into a cavity carved into the platform, called the insertion cavity of the injection component, as a carved cubic piece of a material other than that of the platform that ensures a High chemical compatibility of this element.

The needle inserted through the upper platform and the injection component is made of stainless steel.

3. Sealing system, comprising:

to. Washer: it is a rubber washer inserted in the

circular channel in the injection component, of the lower platform and

the upper platform, and sealing the injection chamber. It has

of notches to accommodate the glass capillaries. It can be from different

materials to ensure chemical compatibility and can also be

disposable. In our case, we have used nitrile washers and

ethylene propylene diene type M rubber (EPDM), but as has been

mentioned above the material can be modified according to

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needs

b. Pressure adjustment system: allows adjustment of pressure on the rubber washers, sealing the injection chamber. The mechanism consists of a screw anchored to the lower platform that passes through the upper platform through an open notch and ends with a pin on the upper part that exerts pressure on the upper platform, adjusting both platforms and providing sealing. The diameter and length of the screw may vary.

4. Gula of union of the inferior platform and the superior platform: it consists of a screw without head and without tip, of variable length, that crosses the inferior and superior platforms and flanked at the ends by two washers, with the purpose of assembling both Hinge-like parts allow simultaneous mobility on the horizontal axis, in order to adjust the distance between modules and therefore between the injection components. In addition, as many modules as desired can be inserted into the same screw, adjusting the length of this according to the number of modules to be inserted.

The platform consisting of a single piece comprises the same components as those described for the modular platform. However, there are differences with this which are described below:

1. Lower platform: consisting of a single piece with several injection components arranged in it.

2. Upper platform: similar to that described for the modular platform.

3. Sealing system: similar to that described for the modular platform.

Gula of union of the lower platform and the upper platform: the design of this element can be similar to that described for the modular platform, or consist of individual screws that cross and assemble each upper platform with the lower platform and are flanked by washers to keep them in position. The main difference lies in the functionality, since this glutton allows the hinge movement of the platforms, but not the adjustment of the distance between injection components, since the distance is established by the lower platform.

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BRIEF DESCRIPTION OF THE DRAWINGS

The description is complements, for an easy understanding of the description that is being made, with a set of photographs where, with an illustrative and non-limiting nature, the following has been represented:

- Figure 1 shows the front view of the one-piece platforms (1.1) and the modular platform (1.2) with the upper platform open. The guide of union of the platform with the injector is also shown (5)

- Figure 2 shows the disassembled reusable platform, observing the different parts and components that form it.

- Figure 3 shows the platform assembled with microfluid glass capillaries.

Below is a list of the different elements represented in the photographs that make up the invention:

1. Platforms

1.1. Unique platform

1.2. Modular platform

2. Lower platform

2.1. Injection component insertion cavity

2.2. Injection component

2.2.1. Injection chamber

2.2.2. Channel to house the glass capillaries

2.2.3. Circular channel surrounding the injection chamber

3. Upper platform

3.1. Injection component insertion cavity

3.2. Injection component

3.2.1. Injection chamber

3.2.2. Channel to house the glass capillaries

3.2.3. Circular channel surrounding the injection chamber

3.3. Needle inserted through the structure and injection component

4. Pressure adjustment system

4.1. T ornillo with nut nut

4.2. Washer

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5. Gula of union of the platform with the injector

PREFERRED EMBODIMENT OF THE INVENTION

Figure 1 shows the two microfluidic platform designs: the one-piece platform (1.1) and the modular platform (1.2) with the upper platform open.

As can be seen in the general figure 2, the reusable platform comprises the lower platform (2), the upper platform (3), the pressure adjustment system (4) and the gliding joint of the platform with the injector (5)

The lower (2) and upper (3) platforms must be manufactured with a material that covers chemical and mechanical needs, selected from plastics or metals such as steel or aluminum. These platforms are designed using graphic design software and produced using 3D printing. The materials used have been a mixture of esters of methacrylic acid, esters of acrylic acid and a photo initiator, such as stainless steel, although other materials could be used.

The injection components (2.2 and 3.2) can form a single piece with the upper and lower platforms, in the case of being manufactured with the same material, or, in the case that the injection components are not of the same material as the lower (2) and upper (3) platforms, these are manufactured as separate parts inserted in the corresponding injection component insertion cavities of the lower and upper platforms (2.1 and 3.1). One of the materials that has been used for this purpose is polytetrafluoroethylene (PTFE), to ensure high chemical compatibility. This piece has been designed using graphic design software and carved using a numerical control machine on a PTFE plate.

The injection chamber (3.2.1) of the injection component inserted in the upper platform (3) is connected to the outside by means of a stainless steel needle (3.3) through which the inlet and outlet flows of the apparatus circulate. In addition, the injection component has circular channels where the rubber washers (4.2) of the sealing system (4) are housed.

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The sealing system (4) is composed of screws (4.1) anchored to the lower platform, which have screw with nut that allows adjusting the pressure between the lower (2) and upper (3) platforms and seal the injection chambers thanks to the rubber washers (4.2) located in the circular channel (2.2.3 and 3.2.3) surrounding the injection chambers (2.2.1 and 3.2.1). The rubber washers (4.2) are manufactured with chemically compatible materials such as nitrile and ethylene propylene diene rubber type M (EPDM). The washers can be manufactured from washers of these materials in which the notches are carved on the surface, or from a nitrile plate or EPDM from which the washer is extracted by puncturing two concentric circumferences and then carving the notch on the surface.

The union glutton (5) assembles the different parts through the lower (2) and upper (3) platforms so that they are joined as a hinge. This gluttony is manufactured with a material selected from plastics and metals such as steel and aluminum and consists of a cylinder of variable length. This system allows independent mobility on the vertical axis of both platforms, as a hinge, and simultaneous mobility of both pieces on the horizontal axis, in order to adjust the distance between platforms.

Figure 2 shows all the individual parts that form the lower platform (2), the upper platform (3) and the pressure adjustment systems (4), described above.

Figure 3 shows the reusable platform for assembled microfluids, with the lower (2) and upper (3) platforms joined by means of the glutton (5), and the injection chambers of both parts (2.2.1 and 3.2.1) sealed by the pressure adjustment system (4).

Claims (3)

5 10 fifteen twenty 25 30 1. Reusable platform to form micro fluid circuits by assembling glass capillaries. The apparatus comprises one or several modules, each formed by a platform, an injector and a sealing system. The platform acts as a support and glues for both injectors and pressure adjustment systems, as well as for glass capillaries. The injector is placed on the platform, attached to it by a glutton that crosses both parts, and this communicates its injection chamber with the outside through a stainless steel needle inserted in it. The sealing system is assembled at the base of the platform, formed by a screw that crosses both the platform and the injector, and a thumb nut that allows pressure adjustment. Both the injector and the platform contain a material injection chamber that ensures good chemical compatibility. Both injection chambers are surrounded by a rubber washer, also formed by a material that ensures its chemical compatibility. By adjusting the sealing system using the wing nut, the injection chambers of the injector and the platform are sealed by their washers, ensuring the tight flow through the glass capillaries. 2. Reusable platform according to claim 1 wherein the injection chambers and the platform or the injector can constitute an indivisible unit and be manufactured as a single piece; or be, the injection chambers, a piece assembled both on the platform and in the injector, and manufactured using different processes and materials. 3. Reusable platform according to claims 1 and 2, wherein the platform can consist of a single module with several injectors and assembly systems or several modules comprising several platforms with their corresponding injectors and assembly systems aligned by means of a gliding through . image 1 Figure 1 image2 Figure 2 image3 Figure 3