CN210015042U

CN210015042U - Three-dimensional bionic SERS substrate

Info

Publication number: CN210015042U
Application number: CN201920651482.5U
Authority: CN
Inventors: 于会山; 赵楠; 李和福; 王文军
Original assignee: Liaocheng University
Current assignee: Liaocheng University
Priority date: 2019-05-08
Filing date: 2019-05-08
Publication date: 2020-02-04
Anticipated expiration: 2029-05-08

Abstract

The utility model provides a three-dimensional bionical SERS base mainly comprises bio-substrate, silver nanolayer, and wherein the bio-substrate is the cicada wing, has even nanometer column array on the surface of cicada wing, through pulse laser deposition technique with silver nanoparticle deposit on the surface of cicada wing, these silver nanoparticles are deposited in the space between nanometer column structure surface and nanometer column structure uniformly. The substrate has high sensitivity, good reproducibility and simple preparation process, can be applied to the direct detection of melamine, has high detection speed and accurate detection result, overcomes the defects of long detection period and complex detection process of the traditional melamine detection method, and has wide application prospect.

Description

Three-dimensional bionic SERS substrate

Technical Field

The utility model relates to a three-dimensional bionical SERS basement belongs to spectral analysis and detects technical field.

Background

The Surface-Enhanced Raman Scattering (SERS) technology is a vibration spectroscopy technology with ultrahigh sensitivity, and a spectrum of the SERS technology contains a large amount of chemical information and can provide information such as the structure and chemical composition of a substance; in addition, the SERS signal has the characteristic of photobleaching resistance, the Raman spectrum peak width is narrow, and the signal is only 1/10-1/100 of fluorescence, so that the detection time can be properly prolonged, and a more ideal signal can be obtained. The SERS technology is increasingly widely applied to the fields of substance detection, molecular recognition, trace analysis, immune recognition, biological imaging and the like. The key point for promoting the application of the SERS technology to the field of substance detection is the active substrate with good reproducibility and high sensitivity. The substrate structure is classified, the SERS substrate can be divided into a one-dimensional SERS substrate, a two-dimensional SERS substrate and a three-dimensional SERS substrate, the three-dimensional SERS substrate is more excellent in reproducibility compared with the one-dimensional SERS substrate and the two-dimensional SERS substrate, the hot spot with higher unit density is provided, and a more ideal enhancement effect can be obtained.

Melamine (chemical formula C)₃N₃（NH₂）₃) Is a triazine nitrogen-containing heterocyclic organic compound and is used as a chemical raw material. It is a white crystal, slightly soluble in water, almost odorless, harmful to the body, a carcinogen, and is banned by the national regulations as a food additive. However, some illegal merchants add melamine into infant formula milk powder to improve the protein content index, which seriously harms the health of infants. At present, internationally universal melamine detection methods comprise high performance liquid chromatography, liquid chromatography-mass spectrometry/mass spectrometry and gas chromatography-mass spectrometry combined methods, but instruments used in the detection methods are expensive, the requirements on detection personnel are high, a sample needs to be treated for a long time in the early detection period, the operation process is complex, and rapid detection of melamine is difficult to realize.

SUMMERY OF THE UTILITY MODEL

In order to prepare the better three-dimensional SERS basement of reinforcing effect, the utility model aims at providing a three-dimensional bionical SERS basement to be applied to this basement to the detection to melamine in the infant formula milk powder.

The utility model adopts the technical proposal that: the nano-silver/. The array structure is uniform, and the substrate can show good signal reproducibility

Preferably, the biological substrate is a cicada wing, and the surface of the biological substrate has certain hydrophobic characteristics.

Preferably, the silver nano-layer is silver nano-particles deposited on the surface of the biological template by a Pulsed Laser Deposition (PLD) technology, and the silver nano-particles can greatly improve the enhancement effect of the substrate. The pulse laser used by the pulse laser deposition system is an excimer laser, the laser wavelength is 248nm, the pulse energy of the laser is 110mJ, the pulse frequency is 5HZ, and the deposition system is a laser molecular beam epitaxy system (LMBE).

Preferably, the thickness of the silver nanolayer is determined by the deposition time.

Preferably, the different deposition time is 15min, 20min, 25min and 30 min.

Preferably, the regular columnar array consists of a plurality of nano columns which are uniformly distributed, the nano columns are thick at the lower part and thin at the upper part, and a certain gap is formed between the columns.

Preferably, the average diameter of the top of the nano-pillars is 40nm, the average diameter of the bottom of the nano-pillars is 150nm, and the average distance between the tops of the two nano-pillars is 180 nm.

The method for performing simulation detection on melamine in infant formula milk powder by using the substrate comprises the following steps: and (3) extracting 5ul of milk powder-melamine mixed solution by using a liquid gun, dripping the milk powder-melamine mixed solution on the surface of the substrate, and directly placing the substrate under a Raman spectrometer for detection after the liquid drops on the surface of the substrate are naturally dried.

The utility model discloses the beneficial effect who produces is: the cicada wing is used as the substrate of the SERS substrate, the nano structure does not need to be constructed manually, and the preparation time and cost are greatly saved. In addition, the substrate has good reproducibility and high sensitivity, and compared with one-dimensional and two-dimensional SERS substrates, the three-dimensional bionic SERS substrate has more abundant hot spots, the enhancement effect of the substrate can be greatly improved, and the enhancement factor of the substrate reaches 1.09 multiplied by 10⁵(ii) a Production of such substrates in contrast to chemically produced SERS substratesThe preparation method is simple and can rapidly carry out large-scale preparation. The substrate is used for detecting melamine, can overcome the defects of long detection period and complex detection process of the traditional melamine detection method, realizes the direct detection of the melamine, and has short detection period and low detection cost.

Drawings

The present invention will be further described with reference to the accompanying drawings and the following detailed description.

FIG. 1 is a block diagram of a three-dimensional biomimetic SERS substrate;

FIG. 2 is an appearance diagram of a three-dimensional bionic SERS substrate;

FIG. 3 is a graph of the results of the R6G test for SERS substrates of example 1 at different deposition times;

FIG. 4 is a graph showing the results of detecting melamine in example 2.

Reference numerals: 1. a bio-substrate; 2. a nano columnar structure on the surface of the biological substrate; 3. a silver nanolayer.

Detailed Description

Example one

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1 and 2, the utility model discloses a bionical SERS base of three-dimensional, including biological substrate 1 and the silver nanolayer of deposit on biological substrate surface, characterized by is at biological substrate surface regular nanometer column array 2, and silver nanolayer is deposited in the surface of nanometer column structure and the space between the nanometer column structure evenly.

A preparation method of a three-dimensional bionic SERS substrate comprises the following steps:

(1) several cicada wings are purchased from the market and cut into 1.2 multiplied by 1.2cm by scissors²The total of 4 cicada wing fragments with the specification are required to be cut.

(2) And (3) putting the cut cicada fin sections into absolute ethyl alcohol for ultrasonic cleaning for 10min, then putting the cicada fin sections into deionized water for ultrasonic cleaning for 10min, cleaning surface residues, blowing off water on the surfaces of the cicada fins by using aurilaves, and naturally drying the cicada fins.

(3) Selecting one of the clean cicada fin sections obtained in the step (2), clamping the edge of the clean cicada fin section by using a pair of tweezers to enable the front side of the cicada fin section to be upward (the front side of the cicada fin section has clear fin vein lines, and the back side of the cicada fin section is smoother), sticking a wide double-sided adhesive (the size of the cicada fin section is equal to or slightly larger than that of the cicada fin section) on a cleaned glass slide, and lightly pressing the edge of the cicada fin section by using the tweezers to smooth the cicada. The other 3 cicada fin sections are respectively stuck on 3 glass slides according to the mode, and all samples are respectively numbered as 1-4.

(4) Adhering No. 1 sample on sample stage of laser molecular beam epitaxy system (LMBE) with vacuum adhesive tape, feeding sample into substrate stage of epitaxial chamber via sample feeding chamber, adjusting the distance between the substrate stage and silver target material to maximum to prevent surface structure of cicada wing from being damaged, and vacuumizing to reach pressure of 2.0 × 10 in the epitaxial chamber^-4Pa。

(5) And (3) opening an excimer laser, and reflecting the laser to the silver target through a lens to deposit the silver nanoparticles on the surface of the cicada wing, wherein the deposition time is controlled to be 15 min. After the deposition is finished, vacuum pumping is continuously carried out for 30min, so that silver nanoparticles deposited on the surfaces of the cicada wings are prevented from being oxidized in the air.

(6) And (5) repeating the step (4) on the samples No. 2-4, and controlling the deposition time to be 20min, 25min and 30min respectively. After the silver nanoparticles are deposited on the samples, the samples need to be continuously vacuumized for 30min in order to prevent the silver nanoparticles from being oxidized.

(7) The mass concentration of the extract is 10 by using a liquid gun^-6And (3) respectively dripping the R6G solution of M on the surfaces of the four samples, wherein the volume of each sample dripping R6G solution is 5ul, and waiting for the dripping to naturally dry.

(8) And after the liquid drops on the surface of the substrate are naturally dried, respectively carrying out Raman tests on the 4 samples by using a Raman spectrometer, wherein the wavelength of the laser used by the Raman spectrometer is 785nm, the power of the laser is 0.3mw, and the integration time is 10 s. Comparison of 1510cm in the R6G spectra among the 4 samples^-1Peak intensity, finding the substrate with silver deposition time of 30min at 1510cm^-1The peak intensity is the highest, i.e. the SERS substrate with the best performance is required. The results of the detection are shown in FIG. 3.

Example two

Application of three-dimensional bionic SERS substrate

The application of the three-dimensional bionic SERS substrate is to detect melamine in infant formula milk powder, and when the simulated sample SERS detection is carried out, the three-dimensional bionic SERS substrate comprises the following steps:

(1) weighing 500mg of infant formula milk powder and 10mg of melamine powder of a certain brand, putting the infant formula milk powder and the melamine powder into two beakers, respectively adding deionized water until the volume of the solution is 100mL to obtain a milk powder solution with the mass concentration of 5g/L and a melamine solution with the mass concentration of 100mg/L, and mixing the melamine solution and the milk powder solution according to a ratio of 1:1 and a ratio of 1: 10 to respectively obtain milk powder-melamine mixed solution with the mass concentration of melamine of 50mg/L and 10 mg/L.

(2) And (2) respectively extracting 5ul of the two milk powder-melamine mixed solutions obtained in the step (1) by using a liquid gun, directly dripping the two milk powder-melamine mixed solutions on the three-dimensional bionic SERS substrate prepared in the embodiment 1, and after the liquid drops on the substrate are naturally dried, directly carrying out Raman detection on the area with the liquid drops by using a Raman spectrometer, wherein the parameters of the Raman spectrometer are the same as those of the embodiment 1, and the detection result is shown in fig. 4.

Claims

1. The three-dimensional bionic SERS substrate is characterized by mainly comprising a biological substrate and silver nanolayers, wherein the surface of the biological substrate is provided with a regular nano columnar array, and the silver nanolayers are uniformly deposited on the surface of the nano columnar structures and in gaps among the nano columnar structures.

2. The three-dimensional bionic SERS substrate according to claim 1, wherein the biological substrate is a cicada wing.

3. The three-dimensional bionic SERS substrate according to claim 1, wherein the silver nano layer is deposited on the surface of the biological substrate by a pulsed laser technology.

4. The three-dimensional biomimetic SERS substrate according to claim 3, wherein the thickness of the silver nanolayer is determined by deposition time.

5. The three-dimensional bionic SERS substrate according to claim 4, wherein the different deposition time is 15min, 20min, 25min and 30 min.

6. The three-dimensional bionic SERS substrate according to claim 1, wherein the regular columnar array is composed of a plurality of nano-pillars which are uniformly distributed, the nano-pillars are thick at the lower part and thin at the upper part, and a certain gap is formed between the pillars.

7. The three-dimensional bionic SERS substrate according to claim 6, wherein the average diameter of the tops of the nano-pillars is 40nm, the average diameter of the bottoms of the nano-pillars is 150nm, and the average distance between the tops of the two nano-pillars is 180 nm.