CN102522490A - Preparation method for glass micro-needle thermocouple - Google Patents

Abstract

The invention discloses a method for preparing a glass microneedle thermocouple in the field of biomedical engineering. carbon thin film; inject metal liquid into the glass microneedle and cool it; grind the tip of the glass microneedle to a certain angle; glass microneedle thermocouple. The process of preparing the glass microneedle thermocouple is simple and easy to operate. Carbon film and biocompatible metal are used as thermocouple materials, with stable thermoelectric properties, sufficient physical and chemical stability, and not easy to be oxidized or corroded; small temperature coefficient of resistance, high conductivity, and small specific heat; good material reproduction, mechanical High strength; good biocompatibility, can be directly applied to the field of biomedicine.

Description

Preparation method of glass microneedle thermocouple

technical field

The invention relates to a method for preparing a glass microneedle thermocouple in the field of biomedical engineering, in particular to a method for preparing a glass microneedle thermocouple using metal inside the glass microneedle and a carbon film on the surface of the microneedle as conductors.

Background technique

With the rapid development of biotechnology and semiconductor technology in the field of micro-nano, more and more attention has been paid to the research on micro-scale structures and materials, especially in the field of experimental technology, which can detect objects with characteristic scales at the micro-nano scale Direct, real-time detection and manipulation has become a hot spot in the field of microscale research, and it is also a challenging research topic for researchers. With the development of atomic force microscope, scanning electron microscope and ultrafast light source, it is possible to study and detect the thermal, mechanical, chemical, electrical, optical and acoustic properties of materials.

Microscale detection technology plays an important role in the study of biological activities and many other physical processes. For example, temperature detection of single cells can provide important data in thermotherapy, cancer detection, activity of metabolites, thyroid disease diagnosis, heat-induced denaturation of nucleic acids and proteins. Real-time detection of individual cell temperature is a hot research field, and studying the thermal response of individual cells in biological processes can provide important physiological information.

The thermocouple can directly measure the temperature, and convert the temperature signal into a thermal electromotive force signal, and convert it into the temperature of the measured medium through an electrical instrument. The basic principle of thermocouple temperature measurement is that two conductors with different components (called thermocouple wire or hot electrode) are connected into a loop at both ends. When the temperature of the two junctions is different, an electromotive force will be generated in the loop. This phenomenon is called thermoelectric effect, and this electromotive force is called thermoelectric force. Among them, the end directly used to measure the temperature of the medium is called the working end (also called the measuring end), and the other end is called the cold end (also called the compensation end). The resulting thermoelectric potential. In the actual temperature measurement application of thermocouples, the form of welding the hot end and opening the cold end is often used. The cold end is connected to the display instrument through the connecting wire to form a temperature measurement system.

Theoretically, any two different conductors (or semiconductors) can be formulated into thermocouples, but as a practical temperature measuring element, there are many requirements for it. In order to ensure the reliability of engineering technology and sufficient measurement accuracy, not all materials can form thermocouples. Generally, the basic requirements for electrode materials of thermocouples are: (1) Stable thermoelectric properties within the temperature measurement range , does not change with time, has sufficient physical and chemical stability, and is not easy to oxidize or corrode; (2), the temperature coefficient of resistance is small, the conductivity is high, and the specific heat is small; (3), the thermoelectric potential generated during temperature measurement is large, and The relationship between thermoelectric potential and temperature is a linear or nearly linear single-value function; (4), the material has good reproducibility, high mechanical strength, simple manufacturing process and low price.

After searching the prior art documents, it was found that R.Shrestha, T.Y.Choi, W.S.Chang et al wrote the article "Micropipette-Based Thermal Sensor for Biological Applications" ("Microneedle-based biological Temperature Sensors" "2010 IEEE Sensors Conference"). In this paper, tin injected into the glass microneedle and nickel deposited on the surface of the glass microneedle were used as thermocouple materials. The thermocouple probe made by this method is limited in application due to the use of metallic nickel, which is toxic to cells.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies and defects of the prior art, and propose a method for preparing a glass microneedle thermocouple, so that the glass microneedle thermocouple can be applied to temperature measurement in the microscale field of biomedicine. Due to the use of biocompatible metal and carbon films as thermocouple materials, it can be directly applied to measure the temperature of single cells.

The present invention is achieved through the following technical solutions. The present invention firstly deposits a layer of polymer film on the glass microneedle, and then puts the glass microneedle into a high-temperature environment for cracking to form a layer of carbon film on the glass microneedle, and then deposits a layer of polymer film on the glass microneedle. The metal liquid is injected into the microneedle and cooled, then the tip of the glass microneedle is ground to a certain angle, and finally a layer of metal is deposited on the tip of the glass microneedle to obtain the final required glass microneedle thermocouple.

The present invention comprises the following steps:

The first step is to deposit a polymer film on the surface of the glass microneedles.

The glass microneedles are quartz glass microneedles.

The size of the tip of the glass microneedle is from micrometer to nanometer.

Said deposition is chemical vapor deposition.

The thickness of the polymer film is micron to nanometer.

In the second step, the glass microneedles are cracked in a high-temperature environment, and a layer of carbon film is formed on the glass microneedles.

The high-temperature cracking refers to putting the polymer film into a cracking furnace filled with a protective atmosphere, and heating at a temperature of 150-1400° C. for 0.5-6 hours.

The third step is to inject the metal liquid into the glass microneedle and cool it down.

The metal liquid is a biocompatible metal with a low melting point and its alloy.

The fourth step is to grind the tip of the glass microneedle into an angle.

The grinding is to grind the tip of the glass microneedle to a desired angle under a needle grinder.

The fifth step is to deposit a layer of metal film on the tip of the glass microneedle to form the thermocouple hot end junction, and obtain the final required glass microneedle thermocouple.

The metal is a biocompatible metal with a thickness ranging from micron to nanometer.

Compared with the prior art, the process of preparing glass microneedle thermocouples in the present invention is simple and easy to operate. Carbon film and biocompatible metal are used as thermocouple materials, with stable thermoelectric properties, sufficient physical and chemical stability, and not easy to be oxidized or corroded; small temperature coefficient of resistance, high conductivity, and small specific heat; good material reproduction, mechanical High strength; good biocompatibility, can be directly applied to the field of biomedicine.

Description of drawings

Fig. 1 is a schematic diagram of the implementation process of Embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of the implementation process of Embodiment 2 of the present invention.

Fig. 3 is a schematic diagram of the implementation process of Embodiment 3 of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below in conjunction with the accompanying drawings: the present embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following Example.

Example 1

As shown in Figure 1, the present embodiment is prepared through the following steps:

The first step, on the surface of the glass microneedle with a tip outer diameter of 0.5 micron, the chemical vapor deposition layer is a 5 micron Parylene C (polychloroparaxylylene) film, as shown in Figure 1a, 1 is the Parylene C film, 2 It is a quartz glass microneedle.

The second step is to put the glass microneedle with the Parylene C film deposited on the surface into a cracking furnace filled with a nitrogen protective atmosphere, and heat it at 900°C for 1 hour (this operation can be performed at a temperature of 150-1400°C for 0.5-6 hours). can implement), crack Parylene C thin film, generate one layer of carbon thin film on glass microneedle, as shown in Figure 1b, 1 is carbon thin film, 2 is quartz glass microneedle.

The third step is to inject lead-free solder liquid into the glass microneedle and cool it down, as shown in Figure 1c, 1 is a carbon film, 2 is a quartz glass microneedle, and 3 is lead-free solder.

The fourth step is to use a needle grinder to grind the tip of the glass microneedle to 45°, as shown in Figure 1d, 1 is a carbon film, 2 is a quartz glass microneedle, and 3 is lead-free solder.

In the fifth step, a 200-nm-thick gold film is deposited on the tip of the glass microneedle to form a thermocouple hot-end junction to obtain the final required glass microneedle thermocouple. As shown in Figure 1e, 1 is a carbon film, and 2 is a Quartz glass microneedle, 3 is lead-free solder, 4 is gold film.

Example 2

As shown in Figure 2, the present embodiment is prepared through the following steps:

The first step is to chemical vapor deposit a layer of PP (polypropylene) film with a thickness of 8 microns on the surface of the glass microneedle with a tip outer diameter of 1 micron, as shown in Figure 2a, 1 is the PP film, and 2 is the quartz glass microneedle.

The second step is to put the glass microneedle with PP film deposited on the surface into a pyrolysis furnace filled with nitrogen protection atmosphere, heat it at 700°C for 1 hour, crack the PP film, and form a layer of carbon film on the glass microneedle, as shown in the figure As shown in 2b, 1 is a carbon film, and 2 is a quartz glass microneedle.

The third step is to inject zinc-magnesium alloy liquid into the glass microneedle in a protective atmosphere and cool it down, as shown in Figure 2c, 1 is a carbon film, 2 is a quartz glass microneedle, and 3 is a zinc-magnesium alloy.

The fourth step is to use a needle grinder to grind the tip of the glass microneedle to 45°, as shown in Figure 2d, 1 is a carbon film, 2 is a quartz glass microneedle, and 3 is a zinc-magnesium alloy.

In the fifth step, deposit a 150-nm-thick gold film on the tip of the glass microneedle to form a thermocouple hot-end junction to obtain the final required glass microneedle thermocouple. As shown in Figure 2e, 1 is a carbon film and 2 is a Quartz glass microneedle, 3 is a zinc-magnesium alloy, and 4 is a gold film.

Example 3

As shown in Figure 3, the present embodiment is prepared through the following steps:

The first step is to chemical vapor deposit a layer of GDP (glow discharge polymer) film with a thickness of 8 microns on the surface of the glass microneedle with a tip outer diameter of 1 micron, as shown in Figure 3a, 1 is the GDP film, and 2 is the quartz glass Microneedles.

The second step is to put the glass microneedle with the GDP film deposited on the surface into a pyrolysis furnace filled with nitrogen protection atmosphere, heat at 500°C for 1 hour, crack the GDP film, and form a layer of carbon film on the glass microneedle, as shown in the figure As shown in 3b, 1 is a carbon film, and 2 is a quartz glass microneedle.

The third step is to inject magnesium metal liquid into the glass microneedle in a protective atmosphere and cool it down, as shown in Figure 3c, 1 is a carbon film, 2 is magnesium, and 3 is a glass microneedle.

The fourth step is to use a needle grinder to grind the tip of the glass microneedle to 30°, as shown in Figure 3d, 1 is a carbon film, 2 is a quartz glass microneedle, and 3 is magnesium metal.

Step 5: Deposit a 200nm-thick gold film on the tip of the glass microneedle to form the thermocouple hot junction, as shown in Figure 3e, 1 is a carbon film, 2 is a quartz glass microneedle, 3 is magnesium metal, 4 It's a gold film.

The process of the above embodiment is simple and easy to operate. Carbon film and biocompatible metal are used as thermocouple materials, with stable thermoelectric properties, sufficient physical and chemical stability, and not easy to be oxidized or corroded; small temperature coefficient of resistance, high conductivity, and small specific heat; good material reproduction, mechanical High strength; good biocompatibility, can be directly applied to the field of biomedicine. It should be understood that the foregoing embodiments are only preferred implementations of the present invention, and the present invention can also be other implementations, such as changing parameters therein (such as high temperature cracking temperature 150-1400° C., parameters such as angle and time).

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the above disclosure. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (9)

1. a preparation method of glass microneedle thermocouple, is characterized in that comprising the following steps: The first step is to deposit a polymer film on the surface of the glass microneedle; The second step is to crack the glass microneedles in a high temperature environment, and form a layer of carbon film on the glass microneedles; The third step is to inject metal liquid into the glass microneedle and cool it down; The fourth step is to grind the tip of the glass microneedle to an angle; The fifth step is to deposit a layer of metal film on the tip of the glass microneedle to form the thermocouple hot end junction, and obtain the final required glass microneedle thermocouple. 2. the preparation method of glass microneedle thermocouple according to claim 1 is characterized in that, described glass microneedle is quartz glass microneedle. 3. The preparation method of the glass microneedle thermocouple according to claim 1 or 2, characterized in that, the tip size of the glass microneedle is from micron to nanometer. 4. The preparation method of glass microneedle thermocouple according to claim 1, characterized in that, said deposition is chemical vapor deposition. 5. The method for preparing a glass microneedle thermocouple according to claim 1, wherein said high-temperature cracking refers to putting the polymer film into a cracking furnace filled with a protective atmosphere and heating it at a temperature of 150 to 1400° C. 0.5 to 6 hours. 6. The method for preparing glass microneedle thermocouples according to claim 1 or 5, characterized in that, the thickness of the polymer film is in the order of microns to nanometers. 7. The method for preparing a glass microneedle thermocouple according to claim 1, wherein the metal liquid is a biocompatible metal with a low melting point and alloys thereof. 8. The preparation method of the glass microneedle thermocouple according to claim 1, characterized in that, the grinding is to grind the tip of the glass microneedle to a desired angle under a needle grinder. 9. The method for preparing a glass microneedle thermocouple according to claim 1, wherein the metal thin film is a biocompatible metal with a thickness of micron to nanometer.

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