CN104961094A - Cell microarray structure based on MEMS process and preparation method of cell microarray structure - Google Patents

Abstract

The invention relates to a cell microarray structure based on MEMS technology and a preparation method thereof. The structure is divided into a groove structure and a column structure. The groove structure is mainly realized by one DRIE dry etching combined with a thermal oxidation process; the pillar structure is mainly realized by two DRIE dry etching combined with a thermal oxidation process, and the silicon micro-nano wires in the array unit are only located on the pillars. Top: The preparation methods used in the above structures are all mature MEMS technology, which has the advantages of low production cost, short production cycle, and batch production.

Description

Cell microarray structure and its preparation method based on MEMS technology

technical field

The invention relates to a cell microarray structure used for cell biology research, in particular to different cell microarrays fabricated on a silicon base substrate by MEMS technology. It belongs to the field of microelectromechanical systems.

Background technique

Currently, the interaction between cells and substrates has attracted great attention in the fields of biology and chemistry. For the fields of biosensing, implantable biomaterials, and tissue engineering, how to control cell adhesion in a specific area is an urgent problem to be solved. Surface structures with nanometer roughness (such as nanoneedles, nanoprotrusions, and nanopores, etc.) have an adhesion effect on cells. These nanostructures have been realized by a series of methods, including nanoimprinting, electron beam nanolithography, and injection molding. .

Cell microarray chips based on microelectromechanical systems (MEMS) have been widely valued by researchers. Micro-scale graphic structures are constructed on the substrate by micro-fabrication technology, and the surface is modified by physical and chemical modification, so that cells can achieve selective adhesion in specific areas, thereby forming an ordered cell microarray. On the cell microarray chip, through the control of the culture environment or the specific design of the adhesion area, the changes in the growth behavior of cells and the changes in related components can be analyzed, and biological and genomic libraries such as cell differentiation, transfection, and intercellular communication can be carried out. Screening, drug screening and other medical research. Combined with fluorescence analysis methods and computational image processing technology, the two-dimensional planar cell array chip has the advantages of convenient focusing, high-throughput screening and fast data processing, which improves the experimental efficiency; at the same time, it realizes the miniaturization of the experimental platform, effectively reducing the research costs.

Contents of the invention

In order to overcome the shortcomings of traditional experimental analysis methods such as biological drug screening that require a large number of samples and cannot be analyzed in real time, the present invention provides a method for preparing a cell microarray structure based on MEMS technology, which at least includes the following steps:

1) providing a silicon substrate;

2) spin-coating photoresist on the upper surface of the silicon substrate, photolithography and developing to form a patterned array structure;

3) using a DRIE etching process to form silicon micro-nano wires on the silicon substrate;

4) Perform thermal oxidation to form a silicon oxide layer.

As one of the preferred solutions of the present invention, the step 3) adopts the DRIE etching process to form silicon micro-nanowires on the silicon substrate. The specific process is as follows: adopt the DRIE etching process to form deep The deep groove is formed with a number of silicon micro-nano wires with a diameter of 200-1000 nanometers and a height of 11-12 micrometers.

As one of the preferred solutions of the present invention, the silicon substrate in step 1) is an SOI silicon wafer.

As one of the preferred solutions of the present invention, the step 3) adopts the DRIE etching process to form silicon micro-nano wires on the silicon substrate. The specific process is as follows: adopt the DRIE etching process to etch the buried layer of the SOI silicon wafer an oxide layer to form a columnar structure; after removing the photoresist, perform a DRIE etching process again to form silicon micro-nano wires on the columnar structure.

As one of the preferred solutions of the present invention, the silicon substrate in step 1) is a single-sided polished (100) crystal-oriented n-type single crystal silicon wafer.

As one of the preferred solutions of the present invention, the step 1) also includes the step of cleaning the silicon substrate.

As one of the preferred solutions of the present invention, the patterned array structure in step 2) is a circular array, each circle has a radius of 10um, and the distance between adjacent circle centers is 40um.

The invention also provides a cell microarray structure.

The present invention adopts MEMS technology with mature technology to realize simple and rapid preparation of different microarray structures. Adhesion culture, the cells will automatically adhere and grow on the treated super-hydrophilic nano-silica region, and finally obtain the designed cell microarray structure with controllable fixed point.

Description of drawings

Figures 1a-1b are schematic diagrams of the groove structure of the present invention.

2a-2b are schematic diagrams of the columnar structure of the present invention.

Fig. 3 is a schematic diagram of the manufacturing process of the groove structure of the present invention.

Fig. 4 is an SEM image of the groove structure of the present invention.

Fig. 5 is a fluorescence image of cell adhesion of the trough structure of the present invention.

Fig. 6 is a schematic diagram of the manufacturing process of the columnar structure of the present invention.

Fig. 7 is an SEM image of the columnar structure of the present invention.

Component designation description

Silicon substrate 3

Patterned photoresist 4, 8

Silicon micro-nano wires 5, 10

Silicon oxide layer 6, 11

Columnar structure 9

Non-microarray structure area 2

circular array 1

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

It should be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic ideas of the present invention, and only the components related to the present invention are shown in the diagrams rather than the number, shape and shape of the components in actual implementation. Dimensional drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component layout type may also be more complicated.

The invention adopts the MEMS technology with mature technology to realize simple and rapid preparation of different microarray structures.

The groove structure and the column structure in the present invention are realized by using MEMS dry etching process combined with thermal oxidation process. The preparation process flow is as follows.

The main production process of the groove structure is as follows:

(1) Select a suitable silicon wafer and clean it.

(2) Photolithography to form the desired microarray pattern.

(3) Silicon micro-nano wires are formed in the microarray unit by DRIE (Deep Reactive Ion Etching, deep reactive ion etching) dry etching process.

(4) Degumming and thermal oxidation are performed to transform the silicon micro-nanowires in the microarray unit into a silicon oxide nanowire structure, so that the microarray area is transformed from superhydrophobic to superhydrophilic.

The main production process of the column structure is as follows:

(1) Select a suitable silicon wafer and clean it.

(2) Photolithography to form the desired microarray pattern.

(3) Forming a columnar structure through a DRIE dry etching process.

(4) Degelling, and forming silicon micro-nano wires on the silicon pillars by DRIE dry etching process again.

(5) Thermal oxidation is performed to transform the silicon micro-nanowires in the microarray unit into a silicon oxide nanowire structure, so that the microarray area changes from superhydrophobic to superhydrophilic. .

After the microarray structure is fabricated, the microarray chip of the required size is obtained by slicing, and the microarray chip is placed in the cell culture medium for cell adhesion culture, and the cells will automatically adhere and grow on the treated super-hydrophilic nano-silicon oxide area , and finally get the designed fixed-point controllable cell microarray structure.

Example 1

As shown in Fig. 1a-1b and Fig. 2a-2b, structure 1 of the present invention is a cell adhesion region, and structure 2 is a planar silicon region.

As shown in Figure 3, the main manufacturing process of the groove structure is as follows:

(1) Select single-side polished (100) crystal-oriented n-type single crystal silicon wafer 3, and perform a standard cleaning process in the semiconductor industry.

Standard cleaning is to remove invisible contamination of atoms and ions. The silicon chip is first cleaned with an acid solution with a composition ratio of H2SO4:H2O2=5:1 or 4:1. The strong oxidizing property of the cleaning solution can decompose and remove the organic matter; after washing with ultra-pure water, use an alkali with a composition ratio of H2O:H2O2:NH4OH=5:2:1 or 5:1:1 or 7:2:1 Due to the oxidation of H2O2 and the complexation of NH4OH, many metal ions form stable soluble complexes and dissolve in water; then use a composition ratio of H2O:H2O2:HCL=7:2:1 or 5 : 2:1 acidic cleaning solution, due to the oxidation of H2O2, the dissolution of hydrochloric acid, and the complexation of chloride ions, many metals generate complex ions that are soluble in water, so as to achieve the purpose of cleaning.

(2) Coating photolithography and developing to form a patterned photoresist layer 4, which is a circular array 1 in this embodiment.

(3) Performing a DRIE etching process. A deep groove is formed in the region 2, and there are several silicon micro-nano wires 5 with a diameter of 200-1000 nanometers and a height of 11-12 micrometers in the groove.

The DRIE etching process uses an ALCATEL etching machine, but the principle is to apply a voltage to the gas C4F8, SF6 and O2 in a container under a low pressure state, so that these particles form a plasma, and the surface of the silicon wafer is bombarded by ions. Etching the unmasked Si, using C4F8 to protect the etched sidewall to achieve a good aspect ratio, using oxygen to quickly clean up the etched residue, so that the etching result has excellent anisotropy and better selectivity.

(4) Degelling and performing thermal oxidation to form a silicon oxide layer 6 .

The oxidation time is 1 hour and the temperature is 1100 degrees Celsius to form a silicon oxide layer; the oxidation process is not limited to this.

(5) Observe its morphology under SEM, as shown in FIG. 5 .

After the trough structure is fabricated, cells are cultured and grown on the diced microarray chip to realize the cell microarray structure. Figure 4 and Figure 5 show the fluorescent micrographs of the fabricated circulating tumor cell microarray.

Example 2

As shown in Figure 6, the main production process of the column structure is as follows:

(1) Select an SOI silicon wafer 7, the thickness of the top silicon layer is 20um, and perform standard cleaning.

(2) Glue coating, photolithography and development to form a patterned photoresist layer 8, which is a circular array structure in this embodiment.

(3) Perform a DRIE etching process until the buried oxide layer is formed to form a columnar structure 9 .

(4) Removing the gel, and performing the DRIE process again to form silicon micro-nanowires 10 on the silicon pillars.

(5) performing thermal oxidation to form the nano-silicon oxide layer 11 .

(6) Observe its morphology under SEM, as shown in FIG. 7 .

The invention designs and prepares a cell microarray structure that can fix cells in a specific area. The use of this microarray structure can provide complete information on the effects of drugs on cells at different times, reduce the number of repeated experiments, and only require a small number of samples, thus providing a convenient and efficient experimental platform for biological researchers.

To sum up, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (8)

1. A method for preparing a cell microarray structure based on MEMS technology, characterized in that: the method at least comprises the following steps: 1) providing a silicon substrate; 2) spin-coating photoresist on the upper surface of the silicon substrate, photolithography and developing to form a patterned array structure; 3) using a DRIE etching process to form silicon micro-nano wires on the silicon substrate; 4) Carry out thermal oxidation process. 2. the cell microarray structure preparation method based on MEMS technology according to claim 1, is characterized in that: described step 3) adopts DRIE etching process to form the concrete technology of silicon micro-nano wire on described silicon substrate as follows A DRIE etching process is used to form a deep groove on the silicon substrate, and a plurality of silicon micro-nanowires with a diameter of 200-1000 nanometers and a height of 11-12 micrometers are formed in the deep groove. 3. The method for preparing a cell microarray structure based on MEMS technology according to claim 1, characterized in that: the silicon substrate in the step 1) is an SOI silicon wafer. 4. the cell microarray structure preparation method based on MEMS technology according to claim 3, is characterized in that: described step 3) adopts DRIE etching process to form the concrete technology of silicon micro-nano wire on described silicon substrate as follows DRIE etching process is used to etch the buried oxide layer of the SOI silicon wafer to form a columnar structure; after removing the photoresist, the DRIE etching process is performed again to form silicon micro-nano wires on the columnar structure. 5 . The method for preparing a cell microarray structure based on MEMS technology according to claim 1 , wherein the silicon substrate in the step 1) is a single-sided polished ( 100 ) crystal-oriented n-type single crystal silicon wafer. 6 . 6 . The method for preparing a cell microarray structure based on MEMS technology according to claim 1 , characterized in that: said step 1) also includes a step of cleaning the silicon substrate. 7 . 7. the cell microarray structure preparation method based on MEMS technology according to claim 1, is characterized in that: in described step 2), patterned array structure is circular array, and each circle radius is 10um, and adjacent circle center distance It is 40um. 8. A cell microarray structure formed by the method for preparing a cell microarray structure based on a MEMS process according to any one of claims 1 to 7.