Black phosphorus / carbon nanotube composite material, preparation method therefor and use thereof

Abstract

The present invention provides a black phosphorus / carbon nanotube composite material, a preparation method therefor, and a use thereof. The preparation method comprises the following steps: (S101) preparing a black phosphorus nanosheet solution by means of a stepwise centrifugation-assisted liquid-phase exfoliation method; (S102) preparing a carbon nanotube solution by means of a liquid-phase exfoliation method; and (S103) preparing a black phosphorus / carbon nanotube composite material by means of a hydrothermal method, wherein the black phosphorus / carbon nanotube composite material prepared by means of a chemical synthesis method comprises black phosphorus and single-walled carbon nanotubes which are closely attached to each other, a three-dimensional network constructed by the carbon nanotubes well covers the surface of black phosphorus nanosheets, and the surfaces of the carbon nanotubes are filled with active electrons, so that a more sensitive detection result can be acquired, the Raman detection limit can be reduced, and the black phosphorus / carbon nanotube composite material is suitable for the detection of urinary tract bacteria.

Description

Black phosphorus / carbon nanotube composite material and preparation method and application thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of urinary tract bacterial detection, and particularly relates to a black phosphorus / carbon nanotube composite material and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of surface plasmon resonance technology, surface-enhanced Raman scattering (SERS) has shown great advantages in the detection of urinary tract bacteria due to its unique fingerprint identification, single-molecule level detection sensitivity, non-destructive data acquisition, no need for complex instruments, simple result analysis and other advantages, and has attracted widespread attention.

[0003] At present, bacterial detection based on SERS usually adopts two methods of labeled indirect detection and unlabeled direct detection. Compared with indirect detection, direct detection without labeling is more convenient, has strong stability and high detection accuracy. Compared with noble metals, composite semiconductor materials with chemical enhancement effect are another kind of surface-enhanced Raman scattering substrate materials. The surface of the composite semiconductor material has a large specific surface area and abundant active electrons, which is beneficial to the adsorption of trace molecules to be detected, and can also indirectly reduce the Raman detection limit. Compared with traditional semiconductor materials, the emerging two-dimensional (2D) material black phosphorus (PB) can effectively adsorb various molecules in trace amounts due to its good biocompatibility, significant electronic conductivity and large active area, which has aroused more interest in this field. In addition, the surface of the carbon nanotube is full of active electrons, which has the effect of chemically enhanced Raman signal. More importantly, the three-dimensional network constructed by the carbon nanotube helps to suppress the re-stacking effect of the black phosphorus nanosheet, which can further improve the carrier mobility, and the double effect makes the black phosphorus / carbon nanotube nanocomposite material obtain more sensitive detection results and reduce the Raman detection limit. The existing black phosphorus / carbon nanotube composite materials mostly study their catalytic properties, and there is no related research on the detection of urinary tract bacteria by using the black phosphorus / carbon nanotube composite material.

[0004] SUMMARY

[0005] An advantage of the present application is to provide a black phosphorus / carbon nanotube composite material and a preparation method and application thereof, wherein the black phosphorus / carbon nanotube composite material prepared by the present application is suitable for application in urinary tract bacterial detection, and can improve the sensitivity of urinary tract bacterial detection, which has important clinical significance for the detection of urinary tract bacteria.

[0006] Another advantage of the present application is to provide a black phosphorus / carbon nanotube composite material and a preparation method and application thereof, wherein the three-dimensional network structure constructed by the carbon nanotube is well wrapped on the surface of the black phosphorus nanosheet, so that the black phosphorus / carbon nanotube composite material forms many gaps and protrusions, which is beneficial to the aggregation of Raman molecules.

[0007] Another advantage of the present application is to provide a black phosphorus / carbon nanotube composite material and its preparation method and application, which is mainly synthesized by chemical methods such as hydrothermal method, fractional centrifugation method, and liquid phase exfoliation method, rather than physical mixing, so that the black phosphorus and carbon nanotubes are closely combined, which is beneficial to the enrichment of Raman molecules, and the surface of the carbon nanotube is full of active electrons, which has the effect of chemically enhancing Raman signal.

[0008] Another advantage of the present application is to provide a black phosphorus / carbon nanotube composite material and its preparation method and application, which can fully utilize the advantage of large specific surface area of black phosphorus to facilitate the enrichment of the to-be-detected Raman molecules, and further obtain enhanced Raman signal to improve the sensitivity of detection.

[0009] Another advantage of the present application is to provide a black phosphorus / carbon nanotube composite material and its preparation method and application, the three-dimensional network constructed by carbon nanotubes helps to inhibit the re-stacking effect of black phosphorus nanosheets, which can further improve the carrier mobility, and the double effect makes the black phosphorus / carbon nanotube composite material obtain more sensitive detection results, and reduces the Raman detection limit.

[0010] Another advantage of the present application is to provide a black phosphorus / carbon nanotube composite material and its preparation method and application, the preparation method is simple, the detection effect is good, and it is of great significance to improve the sensitivity of urinary tract bacterial detection and application in urinary tract detection.

[0011] According to one aspect of the present application, the present application provides a preparation method of a black phosphorus / carbon nanotube composite material, comprising the following steps:

[0012] (S101) preparing a black phosphorus nanosheet solution by adopting a fractional centrifugation assisted liquid phase exfoliation method;

[0013] (S102) preparing a carbon nanotube solution by adopting a liquid phase exfoliation method; and

[0014] (S103) preparing a black phosphorus / carbon nanotube composite material by adopting a hydrothermal method.

[0015] In the step (S101), black phosphorus is added to a solution to prepare a black phosphorus solution, dissolved oxygen in the liquid is removed by inert gas bubbling, ultrasonic treatment is performed, and after centrifugation, the upper light brown liquid is collected, and after washing, a black phosphorus nanosheet solution is obtained.

[0016] In the step (S101), the solution used for dissolving black phosphorus is ethanol, N-methyl pyrrolidone, water or methanol, the selected inert gas is argon, helium or neon, and the solvent used for washing the upper light brown liquid is deionized water and ethanol, acetone, acetonitrile or methanol.

[0017] wherein in the step (S102), single-walled carbon nanotubes are added to a solution to prepare a single-walled carbon nanotube solution, dissolved oxygen in the liquid is removed by bubbling an inert gas, and ultrasonic treatment is performed to obtain a solution of exfoliated single-walled carbon nanotubes.

[0018] wherein in the step (S102), the solvent used for dissolving the single-walled carbon nanotubes is ethanol, water, acetone, acetonitrile or methanol, and the inert gas used is argon, helium or neon.

[0019] wherein in the step (S103), the solution of black phosphorus nanosheets prepared in the step (S101) and the solution of single-walled carbon nanotubes prepared in the step (S102) are mixed in different volume ratios, and then are subjected to ultrasonic treatment and heating in a polytetrafluoroethylene-lined stainless steel autoclave, and are maintained for a predetermined time, and are subjected to centrifugal separation, and the black precipitate obtained after centrifugal separation is washed, and then is vacuum dried to obtain a black phosphorus / carbon nanotube composite material.

[0020] wherein the concentration of the solution of black phosphorus prepared in the above step is 1.9-2.1 mg / ml, the concentration of the solution of single-walled carbon nanotubes prepared is 0.4-0.6 mg / ml, and the volume ratio of the solution of single-walled carbon nanotubes to the solution of black phosphorus nanosheets in the step (S103) is 1:1-1:2.

[0021] According to an embodiment, wherein in the step (S101), black phosphorus is added to a solution of ethanol, N-methylpyrrolidone, water or methanol to prepare a solution of black phosphorus at a concentration of 1 mg / ml, and then dissolved oxygen in the liquid is removed by bubbling argon, helium or neon, and the solution is subjected to ultrasonic treatment at 5°C for 4 hours using a cell sonicator, and then the upper light brown liquid is collected after centrifugal separation at 2000 rpm for 10 minutes, and the collected upper light brown liquid is washed 2-4 times with deionized water and ethanol, acetone, acetonitrile or methanol at a speed of 12000 rpm to obtain a solution of black phosphorus nanosheets.

[0022] wherein in the step (S102), single-walled carbon nanotubes are added to a solution of ethanol, water, acetone, acetonitrile or methanol to prepare a solution of single-walled carbon nanotubes at a concentration of 0.5 mg / ml, and then dissolved oxygen in the liquid is removed by bubbling argon, helium or neon, and the solution is subjected to ultrasonic treatment at 5°C for 1 hour using a cell sonicator to obtain a solution of exfoliated single-walled carbon nanotubes.

[0023] wherein in the step (S103), the black phosphorus nanosheet solution prepared in the step (S101) and the single-walled carbon nanotube solution prepared in the step (S102) are mixed in different volume ratios, and then placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes, heated to 160°C, and kept for 6 hours, and then centrifuged, and the black precipitate obtained by centrifugation is washed with deionized water and ethanol for 2-4 times, and then vacuum dried at 60°C for 12 hours to obtain the black phosphorus / carbon nanotube composite material.

[0024] According to another aspect of the present application, the present application also provides a black phosphorus / carbon nanotube composite material, comprising tightly fitted black phosphorus and single-walled carbon nanotubes, wherein the carbon nanotubes are well wrapped on the surface of the black phosphorus nanosheet, and the surface of the carbon nanotubes is full of active electrons.

[0025] wherein the black phosphorus / carbon nanotube composite material is composed of a plurality of protrusions and gaps, and the sizes of the protrusions and the gaps are 500±100 nm and 150±50 nm, respectively.

[0026] According to another aspect of the present application, the present application also provides an application of a black phosphorus / carbon nanotube composite material, wherein the black phosphorus / carbon nanotube composite material is suitable for application in the detection of urinary tract bacteria, and the black phosphorus / carbon nanotube composite material comprises tightly fitted black phosphorus and single-walled carbon nanotubes.

[0027] wherein the black phosphorus / carbon nanotube composite material is prepared by the above method, and in the application process, the method for detecting urinary tract bacterial infection by using the black phosphorus / carbon nanotube composite material is as follows: (A) Enterococcus faecalis is cultured in LB until the initial concentration of the bacterial strain is about 10 8 CFU / mL; (B) the bacteria are centrifuged at 6000 rpm for 5 minutes, and the obtained precipitate is washed with 0.9% NaCl solution for 3 times; (C) the bacterial suspension is diluted with PBS to 10 7 , 10 6 , 10 5 , and 10 4 CFU / mL, and stored at 4°C for standby; (D) the black phosphorus / carbon nanotube composite material is immersed in bacterial suspensions with different concentrations, and then incubated with a shaking table for 6 hours, and then dried in air at 37°C; and (E) immediately measuring the sample by using a Raman spectrometer. BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1 is a scanning electron microscope photograph of the black phosphorus / carbon nanotube composite material prepared in Example 1 of the present application.

[0029] FIG. 2 is a SERS spectrum of Enterococcus faecalis detected by using the black phosphorus / carbon nanotube composite material prepared in Example 1 of the present application.

[0030] Figure 3 is a scanning electron microscope photo of the black phosphorus / carbon nanotube composite material prepared in Example 2 of the present application.

[0031] Figure 4 is a SERS spectrum of Enterococcus faecalis detected by using the black phosphorus / carbon nanotube composite material prepared in Example 2 of the present application.

[0032] Figure 5 is a scanning electron microscope photo of the black phosphorus / carbon nanotube composite material prepared in Example 3 of the present application.

[0033] Figure 6 is a SERS spectrum of Enterococcus faecalis detected by using the black phosphorus / carbon nanotube composite material prepared in Example 3 of the present application.

[0034] Figure 7 is a SERS spectrum of Enterococcus faecalis with different concentrations detected by using the black phosphorus / carbon nanotube composite material prepared in Example 2 of the present application.

[0035] Figure 8 is a linear relationship between the SERS signal peak intensity at 1514 cm -1 and the concentration of Enterococcus faecalis detected by using the black phosphorus / carbon nanotube composite material prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0036] The following description is presented to enable any person skilled in the art to practice the application as claimed. The preferred embodiments disclosed herein are only examples of the application and alternative embodiments, modifications, improvements, equivalents, and the like can be made thereto without departing from the spirit and scope of the application as set forth in the following claims. The present application is defined by the claims.

[0037] Compared with noble metals, composite semiconductor materials with chemical enhancement effect are another kind of surface-enhanced Raman scattering substrate materials. The surface of composite semiconductor materials has a large specific surface area and abundant active electrons, which is conducive to the adsorption of trace molecules to be detected, and can also indirectly reduce the Raman detection limit. Compared with traditional semiconductor materials, the emerging two-dimensional (2D) material black phosphorus (PB) has good biocompatibility, significant electronic conductivity, and larger active area, which can effectively adsorb various molecules in trace amounts, and has aroused more interest in this field. In addition, the surface of carbon nanotubes is full of active electrons, which has the effect of chemically enhancing Raman signals. More importantly, the three-dimensional network constructed by carbon nanotubes helps to suppress the re-stacking effect of black phosphorus nanosheets, which can further improve the carrier mobility. The double effects make the black phosphorus / carbon nanotube nanocomposite material obtain more sensitive detection results and reduce the Raman detection limit. Existing black phosphorus / carbon nanotube composite materials mostly study their catalytic properties, and there is no related research report on the detection of urinary tract bacteria by using black phosphorus / carbon nanotube composite materials at home and abroad.

[0038] In order to improve the sensitivity of urinary tract bacterial detection, the application provides a preparation method of black phosphorus / carbon nanotube composite material for application in urinary tract bacterial detection.

[0039] According to an embodiment of the application, a preparation method (S100) of black phosphorus / carbon nanotube composite material comprises the following steps:

[0040] (S101) black phosphorus nanosheets are prepared by using a hierarchical centrifugation assisted liquid phase exfoliation method;

[0041] (S102) carbon nanotubes are prepared by using a liquid phase exfoliation method; and

[0042] (S103) black phosphorus / carbon nanotube composite material is prepared by using a hydrothermal method.

[0043] In the step (S101), black phosphorus is added to a solution to prepare a black phosphorus solution, dissolved oxygen in the liquid is removed by inert gas bubbling, ultrasonic treatment is performed, and after centrifugation, the upper light brown liquid is collected, and after washing, a black phosphorus nanosheet solution is obtained, wherein the solution used for dissolving black phosphorus is ethanol, N-methyl pyrrolidone, water or methanol, the selected inert gas is argon, helium or neon, and the solvent used for washing the upper light brown liquid is deionized water and ethanol, acetone, acetonitrile or methanol.

[0044] In the step (S102), single-walled carbon nanotubes are added to a solution to prepare a single-walled carbon nanotube solution, dissolved oxygen in the liquid is removed by inert gas bubbling, ultrasonic treatment is performed, and an exfoliated single-walled carbon nanotube solution is obtained, wherein the solvent used for dissolving single-walled carbon nanotubes is ethanol, water, acetone, acetonitrile or methanol, and the selected inert gas is argon, helium or neon.

[0045] In the step (S103), the black phosphorus nanosheet solution prepared in the step (S101) and the single-walled carbon nanotube solution prepared in the step (S102) are mixed in different volume ratios, then ultrasonic treatment is performed in a polytetrafluoroethylene-lined stainless steel autoclave, heating is performed, a predetermined time is maintained, centrifugal separation is performed, the black precipitate obtained after centrifugation is washed, and then vacuum drying is performed to obtain black phosphorus / carbon nanotube composite material.

[0046] In the step (S103), the concentration of the black phosphorus solution is 1.9-2.1 mg / ml, the concentration of the single-walled carbon nanotube solution is 0.4-0.6 mg / ml, and the volume ratio of the single-walled carbon nanotube solution to the black phosphorus nanosheet solution is 1:1-1:2.

[0047] Example 1

[0048] A preparation method of black phosphorus / carbon nanotube composite material comprises the following steps:

[0049] (S101) Preparation of black phosphorus nanosheets by hierarchical centrifugation assisted liquid phase exfoliation

[0050] Black phosphorus was added into an ethanol solution to prepare a 1 mg / ml black phosphorus solution, then dissolved oxygen in the liquid was removed by argon bubbling, and the solution was ultrasonically treated at 5°C for 4 hours by using a cell ultrasonic crusher, then the upper light brown liquid was collected after centrifugation at 2000 rpm for 10 minutes, after removing the black precipitate, the collected upper light brown liquid was washed with deionized water and ethanol (12000 rpm, 10 minutes) 2-4 times to obtain a black phosphorus nanosheet solution.

[0051] (S102) Preparation of carbon nanotubes by liquid phase exfoliation

[0052] Single-walled carbon nanotubes were added into an ethanol solution to prepare a 0.5 mg / ml single-walled carbon nanotube solution, then dissolved oxygen in the liquid was removed by argon bubbling, and the solution was ultrasonically treated at 5°C for 1 hour to obtain an exfoliated single-walled carbon nanotube solution.

[0053] (S103) Preparation of black phosphorus / carbon nanotube composite material by hydrothermal method

[0054] The black phosphorus nanosheet solution prepared in step (S101) and the single-walled carbon nanotube solution prepared in step (S102) were respectively diluted to 2 mg / ml and 0.5 mg / ml, mixed in a volume ratio of 1:1, and then placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes, and heated to 160°C for 6 hours, then centrifuged, and the black precipitate obtained by centrifugation was washed with deionized water and ethanol 2-4 times, and vacuum dried at 60°C for 12 hours to obtain a black phosphorus / carbon nanotube composite material.

[0055] Figure 1 shows a scanning electron microscope photograph of the black phosphorus / carbon nanotube composite material prepared in this embodiment. As can be seen from Figure 1, the prepared black phosphorus / carbon nanotube is composed of many gaps and protrusions, and a three-dimensional network of carbon nanotubes is well wrapped on the surface of the black phosphorus nanosheet.

[0056] Figure 2 is a SERS spectrum of Enterococcus faecalis detected by using the black phosphorus / carbon nanotube composite material prepared in Example 1 of the present application, which was detected by using a 532 nm Raman instrument (20 μl of the sandwich structure was dropped on a 0.5 x 0.5 cm silicon wafer, dried at 60°C, and then a 532 nm semiconductor laser was used as an excitation source, the laser spot diameter was 12.5 μm, the numerical aperture was 0.55, the laser power was set to 1 mw, and the integration time was 10 s), and a 532 nm Raman instrument (as above), the concentration of Enterococcus faecalis was 2.95 x 10 6 CIU / mL, which was at 1514 cm -1The intensity of the place is 861.71.

[0057] The method for detecting bacteria in the urinary tract (taking Enterococcus faecalis BNCC 186075 as an example) is as follows:

[0058] Enterococcus faecalis was cultured in LB until the initial concentration of the bacterial strain was about 10 8 CFU / mL. Next, the bacteria were centrifuged at 6000 rpm for 5 minutes, and the resulting precipitate was washed 3 times with a NaCl solution (0.9%) to remove residual macromolecules and other growth medium components. Subsequently, the bacterial suspension was diluted to 10 6 CFU / mL with PBS and stored at 4°C for future use. The black phosphorus / carbon nanotube composite material was immersed in a bacterial suspension of different concentrations, incubated on a shaker for 6 hours, and then dried in air at 37°C. Finally, the sample was immediately measured using a Raman spectrometer (532 nm, 50x objective, 1 mw, collection time 10 s).

[0059] Example 2

[0060] A method for preparing a black phosphorus / carbon nanotube composite material, comprising the following steps:

[0061] (S101) Preparing black phosphorus nanosheets by using a hierarchical centrifugation assisted liquid phase exfoliation method

[0062] Black phosphorus was added to an ethanol solution to prepare a 1 mg / ml black phosphorus solution, then dissolved oxygen in the liquid was removed by argon bubbling, and the collected upper light brown liquid was washed with deionized water and ethanol (12000 rpm, 10 minutes) 2-4 times after removing the black precipitate, to obtain a black phosphorus nanosheet solution.

[0063] (S102) Preparing carbon nanotubes by using a liquid phase exfoliation method

[0064] Single-walled carbon nanotubes were added to an ethanol solution to prepare a 0.5 mg / ml single-walled carbon nanotube solution, then dissolved oxygen in the liquid was removed by argon bubbling, and the collected upper light brown liquid was washed with deionized water and ethanol (12000 rpm, 10 minutes) 2-4 times after removing the black precipitate, to obtain a black phosphorus nanosheet solution.

[0065] (S103) Preparing a black phosphorus / carbon nanotube composite material by using a hydrothermal method

[0066] The black phosphorus nanosheet solution prepared in step (S101) and the single-walled carbon nanotube solution prepared in step (S102) are respectively diluted to 2 mg / ml and 0.5 mg / ml, mixed in a volume ratio of 1.5:1, and then placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes, heated to 160°C, and kept for 6 hours. After centrifugal separation, the black precipitate obtained by centrifugation is washed with deionized water and ethanol 2-4 times, and then vacuum dried at 60°C for 12 hours to obtain a black phosphorus / carbon nanotube composite material.

[0067] Figure 3 shows a transmission electron microscope photo of the black phosphorus / carbon nanotube composite material prepared in this embodiment. As can be seen from Figure 4, the prepared black phosphorus / carbon nanotube is composed of many gaps and protrusions, and a three-dimensional network of carbon nanotubes uniformly wraps the surface of the black phosphorus nanosheet. The size of the protrusions and gaps is 500±100 nm and 150±50 nm, respectively.

[0068] Figure 4 is a SERS spectrum of Enterococcus faecalis detected by the black phosphorus / carbon nanotube composite material prepared in this embodiment, and the method steps are the same as above. The concentration of Enterococcus faecalis is 2.95×10 6 CFU / mL, and detected by a 532 nm Raman instrument (as above). The intensity of Enterococcus faecalis at 1514 cm -1 -1 is 1449.41.

[0069] Example 3

[0070] A method for preparing a black phosphorus / carbon nanotube composite material, comprising the following steps:

[0071] (S101) Preparation of black phosphorus nanosheet by hierarchical centrifugation assisted liquid phase exfoliation

[0072] Black phosphorus is added to an ethanol solution to prepare a black phosphorus solution of 1 mg / ml, and then dissolved oxygen in the liquid is removed by argon bubbling. After ultrasonic treatment at 5°C for 4 hours by a cell ultrasonic crusher, the upper light brown liquid is collected after centrifugation at 2000 rpm for 10 minutes. After removing the black precipitate, the collected upper light brown liquid is washed (12000 rpm, 10 minutes) with deionized water and ethanol 2-4 times to obtain a black phosphorus nanosheet solution.

[0073] (S102) Preparation of carbon nanotubes by liquid phase exfoliation

[0074] Single-walled carbon nanotubes are added to an ethanol solution to prepare a single-walled carbon nanotube solution of 0.5 mg / ml, and then dissolved oxygen in the liquid is removed by argon bubbling. After ultrasonic treatment at 5°C for 1 hour by a cell ultrasonic crusher, an exfoliated single-walled carbon nanotube solution is obtained.

[0075] (S103) Preparation of black phosphorus / carbon nanotube composite material by hydrothermal method

[0076] The black phosphorus nanosheet solution prepared in step (S101) and the single-walled carbon nanotube solution prepared in step (S102) were respectively diluted to 2 mg / ml and 0.5 mg / ml, mixed in a volume ratio of 2:1, and then placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes. The temperature was raised to 160°C, and the mixture was kept at this temperature for 6 hours. After centrifugal separation, the black precipitate obtained was washed with deionized water and ethanol for 2-4 times, and then vacuum dried at 60°C for 12 hours to obtain the black phosphorus / carbon nanotube composite material.

[0077] Figure 5 shows the scanning electron microscope photograph of the black phosphorus / carbon nanotube composite material prepared in this embodiment. The prepared black phosphorus / carbon nanotube is composed of many gaps and protrusions, and the three-dimensional network structure of the carbon nanotube is well wrapped on the surface of the black phosphorus nanosheet.

[0078] Figure 6 is the SERS spectrum of Enterococcus faecalis detected by the black phosphorus / carbon nanotube composite material prepared in this embodiment, and the method steps are the same as above. The concentration of Enterococcus faecalis is 2.95 x 10 6 CFU / mL, and the detection is performed by a 532 nm Raman instrument (as above). The intensity of Enterococcus faecalis at 1514 cm -1 -1 is 585.23.

[0079] From the above experimental results, it can be seen that the SERS signal of Enterococcus faecalis detected by the black phosphorus / carbon nanotube composite material prepared in Example 2 is the strongest. This is because the unique three-dimensional network microstructure of the composite material is beneficial to molecular enrichment, and the more matched energy band relationship between black phosphorus and carbon nanotube produces a synergistic enhancement effect. Further sensitivity analysis was performed using the black phosphorus / carbon nanotube composite material prepared in Example 2.

[0080] Example 4

[0081] The preparation method of the black phosphorus / carbon nanotube composite material is the same as that in Example 2 above. The black phosphorus / carbon nanotube composite material prepared by the preparation method of Example 2 was applied to the detection of urinary tract bacteria. In the application process, the specific detection method is as follows: Enterococcus faecalis was cultured in LB until the initial concentration of the bacterial strain was about 10 8 CFU / mL. Next, the bacteria were centrifuged at 6000 rpm for 5 minutes, and the obtained precipitate was washed with NaCl solution (0.9%) for 3 times to remove residual macromolecules and other growth medium components. Subsequently, the bacterial suspension was diluted with PBS to 10 7 , 10 6 , 10 5 , and 10 4The black phosphorus / carbon nanotube composite material was immersed in bacterial suspension of different concentrations, and after incubation in a shaking bed for 6 hours, it was dried in air at 37°C. Finally, the sample was immediately measured using a Raman spectrometer (532 nm, 50x objective, 1 mw, collection time 10 s).

[0082] Sensitivity analysis

[0083] Figure 7 is a SERS spectrum of the black phosphorus / carbon nanotube composite material prepared in Example 2 for detecting Enterococcus faecalis, and the corresponding dose-response curve of the peak intensity at 1514 cm -1 -2.95 x 10 4 CFU / mL. As can be seen from Figure 7, as the concentration of Enterococcus faecalis increases, the SERS signal intensity also gradually increases. 8

[0084] As can be seen from Figure 8, within the range of 2.95 x 10 4 -2.95 x 10 8 CFU / mL, the SERS signal intensity shows a good linear relationship with the logarithm of the concentration of Enterococcus faecalis (BNCC 186075), and the linear regression equation is y = 328.65x - 819.26, R 2 = 0.967. According to the three times signal-to-noise ratio, the detection limit is estimated to be 2.8 x 10 3 CFU / mL. This shows that the black phosphorus / carbon nanotube composite material can achieve extremely high SERS sensitivity detection, and is very suitable for application in the detection of urinary tract bacteria.

[0085] Example 5

[0086] A method for preparing a black phosphorus / carbon nanotube composite material, comprising the following steps:

[0087] (S101) Preparing black phosphorus nanosheets by using a hierarchical centrifugation assisted liquid phase exfoliation method

[0088] Black phosphorus was added to N-methyl pyrrolidone to prepare a 1 mg / ml black phosphorus solution, and then dissolved oxygen in the liquid was removed by argon bubbling. After ultrasonic treatment at 5°C for 4 hours using a cell ultrasonic crusher, the upper light brown liquid was collected after centrifugation at 2000 rpm for 10 minutes, and after removing the black precipitate, the collected upper light brown liquid was washed with deionized water and acetonitrile (12000 rpm, 10 minutes) 2-4 times to obtain a black phosphorus nanosheet solution.

[0089] (S102) Preparing carbon nanotubes by using a liquid phase exfoliation method

[0090] ​A single-walled carbon nanotube solution of 0.4 mg / ml was prepared by adding single-walled carbon nanotubes into a methanol solution, removing dissolved oxygen in the liquid by argon bubbling, and ultrasonic treatment at 5°C for 1 hour using a cell ultrasonic crusher to obtain a single-walled carbon nanotube solution after exfoliation.

[0091] (S103) Preparation of black phosphorus / carbon nanotube composite material by hydrothermal method

[0092] The black phosphorus nanosheet solution prepared in step (S101) and the single-walled carbon nanotube solution prepared in step (S102) were respectively diluted to 1.9 mg / ml and 0.4 mg / ml, mixed in a volume ratio of 1:1, and then placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes, heated to 160°C, and kept for 6 hours. After centrifugal separation, the black precipitate obtained by centrifugation was washed with deionized water and ethanol 2-4 times, and vacuum dried at 60°C for 12 hours to obtain a black phosphorus / carbon nanotube composite material.

[0093] Example 6

[0094] A method for preparing a black phosphorus / carbon nanotube composite material, comprising the following steps:

[0095] (S101) Preparation of black phosphorus nanosheet by hierarchical centrifugation assisted liquid phase exfoliation method

[0096] A black phosphorus solution of 2 mg / ml was prepared by adding black phosphorus into methanol, removing dissolved oxygen in the liquid by helium bubbling, and ultrasonic treatment at 5°C for 4 hours using a cell ultrasonic crusher. After centrifugation at 2000 rpm for 10 minutes, the upper light brown liquid was collected, the black precipitate was removed, and the collected upper light brown liquid was washed (12000 rpm, 10 minutes) with deionized water and methanol 2-4 times to obtain a black phosphorus nanosheet solution.

[0097] (S102) Preparation of carbon nanotube by liquid phase exfoliation method

[0098] A single-walled carbon nanotube solution of 0.5 mg / ml was prepared by adding single-walled carbon nanotubes into an acetone solution, removing dissolved oxygen in the liquid by helium bubbling, and ultrasonic treatment at 5°C for 1 hour using a cell ultrasonic crusher to obtain a single-walled carbon nanotube solution after exfoliation.

[0099] (S103) Preparation of black phosphorus / carbon nanotube composite material by hydrothermal method

[0100] The black phosphorus nanosheet solution prepared in step (S101) and the single-walled carbon nanotube solution prepared in step (S102) are respectively diluted to 2 mg / ml and 0.5 mg / ml, mixed in a volume ratio of 1.5:1, placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes, heated to 160°C, and kept for 6 hours, then centrifuged, and the black precipitate obtained by centrifugation is washed with deionized water and ethanol for 2-4 times, and vacuum dried at 60°C for 12 hours to obtain a black phosphorus / carbon nanotube composite material.

[0101] Example 7

[0102] A method for preparing a black phosphorus / carbon nanotube composite material, comprising the following steps:

[0103] (S101) Preparation of black phosphorus nanosheet by hierarchical centrifugation assisted liquid phase exfoliation

[0104] Black phosphorus is added to an aqueous solution to prepare a black phosphorus solution of 2.1 mg / ml, then the dissolved oxygen in the liquid is removed by neon gas bubbling, and the liquid is treated with a cell ultrasonic crusher at 5°C for 4 hours, then centrifuged at 2000 rpm for 10 minutes to collect the upper light brown liquid, remove the black precipitate, and wash the collected upper light brown liquid with deionized water and acetone (12000 rpm, 10 minutes) for 2-4 times to obtain a black phosphorus nanosheet solution.

[0105] (S102) Preparation of carbon nanotubes by liquid phase exfoliation

[0106] Single-walled carbon nanotubes are added to an aqueous solution to prepare a single-walled carbon nanotube solution of 0.6 mg / ml, then the dissolved oxygen in the liquid is removed by neon gas bubbling, and the liquid is treated with a cell ultrasonic crusher at 5°C for 1 hour to obtain an exfoliated single-walled carbon nanotube solution.

[0107] (S103) Preparation of black phosphorus / carbon nanotube composite material by hydrothermal method

[0108] The black phosphorus nanosheet solution prepared in step (S101) and the single-walled carbon nanotube solution prepared in step (S102) are respectively diluted to 2.1 mg / ml and 0.6 mg / ml, mixed in a volume ratio of 2:1, placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes, heated to 160°C, and kept for 6 hours, then centrifuged, and the black precipitate obtained by centrifugation is washed with deionized water and ethanol for 2-4 times, and vacuum dried at 60°C for 12 hours to obtain a black phosphorus / carbon nanotube composite material.

[0109] Example 8

[0110] A method for preparing a black phosphorus / carbon nanotube composite material, comprising the following steps:

[0111] (S101)Preparation of black phosphorus nanosheet by hierarchical centrifugation assisted liquid phase exfoliation method

[0112] Black phosphorus was added to an N-methylpyrrolidone solution to prepare a 2 mg / ml black phosphorus solution, then dissolved oxygen in the liquid was removed by argon bubbling, and the collected upper light brown liquid was washed with deionized water and acetone (12000 rpm, 10 minutes) 2-4 times after removing the black precipitate, to obtain a black phosphorus nanosheet solution.

[0113] (S102)Preparation of carbon nanotube by liquid phase exfoliation method

[0114] Single-walled carbon nanotubes were added to an acetonitrile solution to prepare a 0.5 mg / ml single-walled carbon nanotube solution, then dissolved oxygen in the liquid was removed by argon bubbling, and the collected upper light brown liquid was washed with deionized water and acetone (12000 rpm, 10 minutes) 2-4 times after removing the black precipitate, to obtain a black phosphorus nanosheet solution.

[0115] (S103)Preparation of black phosphorus / carbon nanotube composite material by hydrothermal method

[0116] The black phosphorus nanosheet solution prepared in step (S101) and the single-walled carbon nanotube solution prepared in step (S102) were respectively diluted to 2 mg / ml and 0.5 mg / ml, mixed in a volume ratio of 1.8:1, and then placed in a polytetrafluoroethylene-lined stainless steel autoclave for ultrasonic treatment for 10 minutes, and heated to 160 DEG C for 6 hours, then centrifuged, and the black precipitate obtained by centrifugation was washed with deionized water and ethanol 2-4 times, and vacuum dried at 60 DEG C for 12 hours to obtain a black phosphorus / carbon nanotube composite material.

[0117] As can be seen from the above embodiments, the black phosphorus / carbon nanotube composite material provided by the application includes tightly fitted black phosphorus and single-walled carbon nanotubes synthesized by a chemical method, wherein the three-dimensional network of the carbon nanotubes is well wrapped on the surface of the black phosphorus nanosheet, and the surface of the carbon nanotube is full of active electrons, which has the effect of chemically enhancing the Raman signal. The three-dimensional network of the carbon nanotube helps to inhibit the re-stacking effect of the black phosphorus nanosheet, and can further improve the carrier mobility, so that the black phosphorus / carbon nanotube composite material obtains more sensitive detection results, reduces the Raman detection limit, and is suitable for application in the detection of urinary tract bacteria, and is worthy of clinical popularization and application.

[0118] Those skilled in the art will understand that the embodiments of the application described above and shown in the drawings are merely illustrative and that numerous other modifications and configurations can be devised without departing from the principles of the present application. The scope of the application is best defined by the appended claims.

Claims

1. A method for preparing a black phosphorus / carbon nanotube composite material, characterized by, The method comprises the following steps: (S101) preparing a black phosphorus nanosheet solution by a hierarchical centrifugation-assisted liquid phase exfoliation method; (S102) preparing a carbon nanotube solution by a liquid phase exfoliation method; and (S103) preparing a black phosphorus / carbon nanotube composite material by a hydrothermal method.

2. The method according to claim 1, wherein in the step (S101), black phosphorus is added to a solution to prepare a black phosphorus solution, dissolved oxygen in the solution is removed by bubbling an inert gas, the solution is ultrasonically treated, and after centrifugation, the upper light brown liquid is collected to obtain the black phosphorus nanosheet solution after washing.

3. The method according to claim 2, wherein in the step (S101), the solution for dissolving the black phosphorus is ethanol, N-methyl pyrrolidone, water or methanol, the inert gas is argon, helium or neon, and the solvent for washing the upper light brown liquid is deionized water and ethanol, acetone, acetonitrile or methanol.

4. The method according to claim 1, wherein in the step (S102), single-walled carbon nanotubes are added to a solution to prepare a single-walled carbon nanotube solution, dissolved oxygen in the solution is removed by bubbling an inert gas, and the solution is ultrasonically treated to obtain the exfoliated single-walled carbon nanotube solution.

5. The method according to claim 4, wherein in the step (S102), the solvent for dissolving the single-walled carbon nanotubes is ethanol, water, acetone, acetonitrile or methanol, and the inert gas is argon, helium or neon.

6. The method according to claim 1, wherein in the step (S103), the black phosphorus nanosheet solution prepared in the step (S101) and the single-walled carbon nanotube solution prepared in the step (S102) are mixed in different volume ratios, and then ultrasonically treated and heated in a polytetrafluoroethylene-lined stainless steel autoclave for a predetermined time, centrifuged, washed, and vacuum dried to obtain the black phosphorus / carbon nanotube composite material.

7. The method according to any one of claims 1 to 6, wherein the concentration of the black phosphorus solution is 1.9-2.1 mg / mL, the concentration of the single-walled carbon nanotube solution is 0.4-0.6 mg / mL, and in the step (S103), the volume ratio of the single-walled carbon nanotube solution to the black phosphorus nanosheet solution is 1:1-1:

2.

8. The method of claim 1 to 6, wherein in the step (S101), black phosphorus is added to an ethanol, N-methylpyrrolidone, water or methanol solution to form a 1 mg / ml black phosphorus solution, then dissolved oxygen in the liquid is removed by bubbling argon, helium or neon gas, and the solution is ultrasonically treated for 4 hours at 5°C using a cell ultrasonic crusher, after which the upper light brown liquid is collected by centrifugation at 2000 rpm for 10 minutes, the black precipitate is removed, and the collected upper light brown liquid is washed 2-4 times with deionized water and ethanol, acetone, acetonitrile or methanol at a speed of 12000 rpm to obtain a black phosphorus nanosheet solution.

9. The method of claim 8, wherein in the step (S102), single-walled carbon nanotubes are added to an ethanol, water, acetone, acetonitrile or methanol solution to form a 0.5 mg / ml single-walled carbon nanotube solution, then dissolved oxygen in the liquid is removed by bubbling argon, helium or neon gas, and the solution is ultrasonically treated for 1 hour at 5°C using a cell ultrasonic crusher to obtain an exfoliated single-walled carbon nanotube solution.

10. The method of claim 9, wherein in the step (S103), the black phosphorus nanosheet solution prepared in the step (S101) and the single-walled carbon nanotube solution prepared in the step (S102) are mixed in different volume ratios, then placed in a polytetrafluoroethylene-lined stainless steel autoclave and ultrasonically treated for 10 minutes, heated to 160°C and kept for 6 hours, after which centrifugal separation is performed, the black precipitate obtained by centrifugation is washed 2-4 times with deionized water and ethanol, and vacuum dried at 60°C for 12 hours to obtain a black phosphorus / carbon nanotube composite material.

11. A black phosphorus / carbon nanotube composite material, characterized by, The black phosphorus / carbon nanotube composite material comprises tightly fitted black phosphorus and single-walled carbon nanotubes, wherein the carbon nanotubes form a three-dimensional network that well wraps the surface of the black phosphorus nanosheets, and the surface of the carbon nanotubes is full of active electrons.

12. The black phosphorus / carbon nanotube composite material of claim 11, wherein the black phosphorus / carbon nanotube composite material is composed of a plurality of protrusions and gaps, and the size of the protrusions and gaps is 500±100 nm and 150±50 nm, respectively.

13. The black phosphorus / carbon nanotube composite material of claim 11 or 12, wherein the black phosphorus / carbon nanotube composite material is prepared by the method of any one of claims 1 to 9.

14. Use of a black phosphorus / carbon nanotube composite material, characterized in that The black phosphorus / carbon nanotube composite material is suitable for application in the detection of urinary tract bacteria, wherein the black phosphorus / carbon nanotube composite material comprises tightly fitted black phosphorus and single-walled carbon nanotubes.

15. The use of the black phosphorus / carbon nanotube composite material according to claim 14, wherein the black phosphorus / carbon nanotube composite material is prepared by the black phosphorus / carbon nanotube composite material of claims 1 to 14, and in the process of use, the method for detecting urinary tract bacterial infection is as follows: (A) Enterococcus faecalis is cultured in LB until the initial concentration of bacterial strains is about 10 8 CFU / mL; (B) the bacteria are centrifuged at 6000 rpm for 5 minutes, and the obtained precipitate is washed with 0.9% NaCl solution for 3 times; (C) the bacterial suspension is diluted with PBS to 10 7 , 10 6 , 10 5 and 10 4 CFU / mL, and stored at 4°C for standby; (D) the black phosphorus / carbon nanotube composite material is immersed in bacterial suspensions with different concentrations, and after incubation with a shaker for 6 hours, it is dried in air at 37°C; and (E) the sample is immediately measured by using a Raman spectrometer.

Images