Preparation and application of binary nano composite material Bi NPs / PCN-224

Abstract

The invention discloses a preparation method of a binary nano composite material Bi NPs / PCN-224, which comprises the following steps: firstly, preparing PCN-224 by a hydrothermal method, then dissolving the PCN-224 material in deionized water, performing ultrasonic activation, adding Bi (NO3) 2.5 H2O into the PCN-224 material, reducing by using a NaBH4 aqueous solution, performing ultrasonic treatment until Bi (NO3) 2.5 H2O is completely dissolved to obtain a mixed solution, uniformly stirring, washing, and drying to obtain the binary nano composite material Bi NPs / PCN-224. And drying to obtain the novel nano material Bi NPs / PCN-224 with various biomedical functions. The prepared composite photocatalyst has a large specific surface area and more active sites, and can be used for photocatalytic antibiosis and anticancer.

Description

Technical Field

[0001] The present invention relates to the preparation of a binary nanocomposite material Bi NPs / PCN-224 with diverse biomedical functions and its application in photocatalytic antibacterial and anticancer properties, belonging to the technical fields of composite material preparation and biomedicine. Background Art

[0002] Bismuth nanoparticles (Bi-NPs) are commonly used on semiconductor surfaces to enhance photocatalytic activity due to their surface plasmon resonance (SPR) effect. Bi-NPs can act as both electron acceptors and plasmon-like electron donors. This involves the interaction of electrons with the metallic Bi and the semiconductor CB, promoting the separation of photogenerated electron-hole pairs. Bi has been reported to have dual medicinal properties in wound healing (including postoperative) and burn dressings, antibacterial hydrogels, and many cosmetics. Bi has relatively low toxicity to mammals, and bismuth compounds are absorbed through the respiratory and gastrointestinal tracts, which offers certain advantages over other metals. However, because Bi NPs are highly unstable and prone to agglomeration, they are easily oxidized to Bi ions under physiological conditions, which greatly hinders their practical application. Summary of the Invention

[0003] The present invention aims to provide a method for preparing a binary nanocomposite material Bi NPs / PCN-224. The binary nanocomposite material is a novel nanomaterial with diverse biomedical functions and can be used in photocatalytic antibacterial and anticancer activities.

[0004] 1. Preparation of binary nanocomposite (Bi NPs / PCN-224) (1) Preparation of PCN-224: Use DMF as solvent, ZrOCl2·8H2O and TCPP as raw materials, and benzoic acid as morphology modifier. Stir and react at 90~150℃ for 1~2 h, filter, wash, and vacuum dry to obtain spherical PCN-224.

[0005] The mass ratio of the ZrOCl2·8H2O to TCPP is 1:2-1:5. The mass ratio of the benzoic acid to TCPP is 1:3-1:4.

[0006] (2) Preparation of Bi NPs / PCN-224: Using ethylene glycol and deionized water as solvents, PCN-224 and Bi(NO3)3·5H2O as raw materials, polyvinyl pyrrolidone as surfactant, and sodium borohydride as reducing agent, the in situ precipitation method was used to mix and react at room temperature for 1~4h, centrifuge and wash, and vacuum dry to obtain Bi NPs / PCN-224 binary composite materials.

[0007] The mass ratio of PCN-224 to Bi(NO3)3·5H2O is 1:2 to 1:3. The mass ratio of NaBH4 to Bi(NO3)3·5H2O is 1:1 to 1:2. The mass ratio of Bi(NO3)3·5H2O to polyvinylpyrrolidone is 3:1 to 1:1.

[0008] Figure 1 A is a schematic diagram of the synthesis of Bi NPs / PCN-224.

[0009] 2. Characterization of the Photocatalytic Performance of Binary Nanocomposites (Bi NPs / PCN-224) The photoelectrochemical characterization was carried out using an electrochemical workstation. Using a standard three-electrode system, each material was added dropwise to an ITO glass (active area of ​​1 cm) used as a WE. 2 ) on the surface. Ag / AgCl platinum foils served as CE and RE, respectively, and the electrolyte was 0.5 M Na₂SO₄. A 50W LED light source (λ ≥ 420 nm) was used for IT, EIS, and Mott-Schottky measurements. Ultraviolet-visible diffuse reflectance (UV-vis) measurements were also performed.

[0010] Figure 2 In the figure a it, the instantaneous photocurrent intensity generated by the Bi NPs / PCN-224 composite material is the highest, which verifies that the composite material has good electron-hole pair separation ability. Figure 2 b In the EIS diagram, the semicircle corresponds to the impedance value of the electrolyte / nanomaterial interface. It can be seen that the diameter of the semicircle of the Nyquist diagram becomes smaller after the Bi NPs and PCN-224 are composited, which proves that the BiNPs / PCN-224 composite material has an effective charge transfer effect and good photocatalytic performance. Figure 2 c In the fluorescence spectrum (PL graph), the higher the PL intensity, the higher the e- / h+ recombination rate, and the lower the photoactivity of the semiconductor. Among the three materials, Bi NPs / PCN-224 has the lowest PL intensity and the highest photoactivity. Figure 2 In the Mott-Schottky plots of various materials, the Mott-Schottky curve of Bi NPs shows a positive slope, and the Fermi level is close to the bottom of the conduction band, while the Mott-Schottky curve of PCN-224 shows a negative slope, and the Fermi level is close to the top of the valence band. When these two semiconductors come into contact with each other, electrons flow to PCN-224, causing an internal potential in the space charge region of Bi NPs / PCN-224 at the heterojunction interface space, driving and accelerating the separation of photogenerated carriers. The flat band potentials E (Ag / AgCl) of Bi NPs, PCN-224, and Bi NPs / PCN-224 are 3.27 eV, 1.78 eV, and 1.72 eV, respectively. Figure 2fh are the VB-XPS images of Bi NPs, PCN-224, and Bi NPs / PCN-224, respectively. VB The (XPS) values ​​are 1.79 eV, 3.26 eV, and 3.04 eV, respectively. Based on formulas 1 and 2, the E of each material can be calculated. VB Value, E VB (Bi NPs), E VB (PCN-224), E VB (Bi NPs / PCN-224) are 1.897 eV, 4.057 eV, and 1.757 eV, respectively.

[0011] E (NHE, pH 7) = E (Ag / AgCl) + 0.198 eV (1) E VB =E VB (XPS)+ E (NHE, pH7) (2) Figure 3 UV-vis diagrams, Tacu diagrams of each material, and band structure spectra of Bi NPs and PCN-224. Figure 3 In a, the addition of Bi NPs enhances the absorption of the material after 500 nm. According to the Tauc plot and UV-vis, the band gap width (E g ) are 3.27, 1.78 and 1.72 eV respectively ( Figure 3 b) According to formula 3, E can be calculated CB The values ​​are -1.373 eV, 2.277 eV, and 0.037 eV, respectively. Thus, the band structure spectrum can be obtained, as shown in Figure 3 As shown in c.

[0012] E CB =E VB -E g (3) Based on the above results, the photocatalytic mechanism of Bi NPs / PCN-224 was proposed. Under light conditions, the photogenerated electrons in the CB of Bi NPs will react with the h in the VB of PCN-224. + The recombination of photogenerated electrons and holes leads to a high separation rate of photogenerated electrons and holes, and the efficient charge carrying separation results in the retention of the accumulated h + , while PCN-224 retains e in CB - Therefore, the photogenerated electrons in the BiNPs (-1.373 eV) CB will be able to reduce O2 to -O2 - Because their CB potential is higher than O2 / -O2- The CB potential of PCN-224 is more negative (-0.33 eV vs. NHE), and the accumulated PCN-224 h+ in the valence band can oxidize H2O molecules to ·OH, because the VB potential of PCN-224 (4.057 eV) is more positive than the VB potential of H2O / ·OH (+2.72 eV vs. NHE). As a result, a large amount of -O2 - and ·OH reactive oxygen species (ROS).

[0013] 3. Antibacterial properties of binary nanocomposites (Bi NPs / PCN-224) Take resistance to Staphylococcus aureus (S.aureus), Escherichia coli (E.coil), and drug-resistant bacteria (MRSA) as an example.

[0014] All strains (S. aureus, E. coli, and MRSA) were streaked onto LB plates and incubated at 37°C for 24 h. One colony was removed from each plate and inoculated into fresh sterilized LB solution (5 mL), which was then incubated at 37°C overnight. The broth after overnight incubation was further diluted to approximately 10 -4 Colony forming units (CFU.mL −1 The bacterial concentration used for antibacterial testing was approximately 10 -4 CFU.mL −1 Three parallel experiments were performed for each antibacterial process.

[0015] Bacteria photos on agar plates and histogram of bacterial colony counts ( Figure 4 ), showing the photocatalytic antibacterial efficiency of different materials at 1 mg / mL against three different bacterial species. Under dark conditions, the bacterial removal rates of Bi NPs, PCN-224, and Bi NPs / PCN-224 were far lower than those under light conditions. While Bi NPs and PCN-224 could kill a small number of bacteria, they were not completely effective in killing the bacteria. In comparison, the Bi NPs / PCN-224 binary heterojunction nanomaterial achieved a bactericidal efficiency of 98.3% against Staphylococcus aureus (S. aureus), 99.1% against Escherichia coli (E. coli), and 98.6% against drug-resistant bacteria. This is primarily because under light conditions, the reactive oxygen species produced by Bi NPs / PCN-224 first destroy the bacterial cell membrane and cell wall. Furthermore, Bi NPs may damage the bacterial cell membrane, leading to nutrient loss and bacterial death.

[0016] Based on the above results, the antibacterial profiles of Bi NPs, PCN-224, and Bi NPs / PCN-224, as well as the inhibition rates, were proposed, e.g. Figure 4 The antibacterial mechanism is shown in Figure 1As shown in Figure B, first, based on the physical damage mechanism, Bi NPs / PCN-224 binary nanomaterials release Bi NPs, which can directly destroy the bacterial cell wall, resulting in the loss of nutrients in the bacterial cells and the death of the bacteria; on the other hand, based on the photocatalytic antibacterial mechanism, under light conditions, Bi NPs / PCN-224 produces a large amount of ROS, which directly kills bacteria.

[0017] IV. Characterization of the inhibitory effect of binary nanocomposites (Bi NPs / PCN-224) on HepG2 cell growth The MTT method was used to test the tumor cell inhibition. The inhibitory effects of different concentrations of Bi NPs / PCN-224 nanocomposites on the proliferation of tumor HepG2 cells were as follows: Figure 5 The Bi NPs / PCN-224 binary nanomaterial exhibited a significant inhibitory effect on HepG2 cells. As the concentration of the Bi NPs / PCN-224 binary nanomaterial increased, the inhibitory rate of the composite material on HepG2 cells also gradually increased, reaching a maximum of 58%. These data suggest that the Bi NPs / PCN-224 nanocomposite has potential as an anti-tumor drug and is expected to undergo further research in the future.

[0018] In summary, the present invention provides a method for preparing novel nanomaterials with diverse biomedical functions. First, a biocompatible zirconium-based porphyrin MOF is prepared, using PCN-224 as a carrier. The standard potential of Zr is more negative than that of Bi, significantly improving the stability and dispersibility of Bi-NPs. Because Bi is incorporated into PCN-224, its redox potential provides sufficient conditions for electron flow into bacteria, thereby achieving significant bactericidal and anticancer effects without exogenous stimulation or the release of antimicrobial factors. The present invention has a simple preparation method, and the nanomaterial platform has a large specific surface area, numerous active sites, and excellent antimicrobial and anticancer properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the synthesis of Bi NPs / PCN-224 and its antibacterial and anticancer mechanism.

[0020] Figure 2Figures characterizing the photocatalytic performance of Bi NPs / PCN-224. (a) Photocurrent response of each material; (b) Impedance diagram of each material; (c) Fluorescence spectra of each material; (d) Mott-Schottky plot of Bi NPs; (e) Mott-Schottky plot of PCN-224; (f) Mott-Schottky plot of Bi NPs / PCN-224; (g) VB-XPS plot of Bi NPs; (h) VB-XPS plot of PCN-224; (i) VB-XPS plot of Bi NPs / PCN-224.

[0021] Figure 3 .(a) UV-vis diagram, (b) Tacu diagram, and (c) energy band spectrum of each material.

[0022] Figure 4 Photocatalytic antibacterial images of PCN-224, Bi NPs, and Bi NPs / PCN-224.

[0023] Figure 5 The inhibitory effect of Bi NPs / PCN-224 nanocomposites with different concentrations on the proliferation of tumor HepG2 cells. DETAILED DESCRIPTION

[0024] The present invention will be further explained below with reference to specific embodiments. Example

[0025] (1) Preparation of PCN-224: In a round-bottom flask, 0.015 g ZrOCl2·8H2O and 0.016 g C7H6O2 (benzoic acid) were dissolved in 50 mL DMF. Subsequently, 0.052 g TCPP was added. The color of the solution changed from colorless to dark purple. The mixture was heated at 120°C for 1 h. After cooling to room temperature, the product was washed several times with ethanol and deionized water. The precipitate was placed in a vacuum drying oven and dried at 60°C for 12 h to obtain spherical PCN-224.

[0026] Preparation of Bi NPs / PCN-224: 0.043 g PCN-224 was dissolved in 50 mL of deionized water and ultrasonicated for 5 min. 0.1004 g Bi(NO3)3·5H2O was dissolved in 50 mL of ethylene glycol and ultrasonicated for 5 min. The PCN-224 solution was added and stirred at room temperature for 2 h. During the stirring process, 25 mL of NaBH4 solution (concentration 4 mg / mL) prepared with ice water and 0.05 g polyvinylpyrrolidone (PVP) were added. After the reaction was completed, the solution was centrifuged at 8000 rpm for 5 min, washed three times with deionized water and ethanol solution respectively, and the precipitate was placed in a vacuum drying oven and dried at 60°C for 12 h to successfully obtain BiNPs / PCN-224 binary composite material. When used for photocatalytic antibacterial treatment, the sterilization rate against Staphylococcus aureus (S. aureus) was 98.3%, against Escherichia coli (E. coli) was 99.1%, and against drug-resistant bacteria was 98.6%.

Claims

1. A method for preparing a binary nanocomposite material Bi NPs / PCN-224, characterized in that: The following steps are involved: (1) Preparation of PCN-224: Use DMF as solvent, ZrOCl2·8H2O and TCPP as raw materials, and benzoic acid as morphology modifier. Stir and react at 90~150℃ for 1~2 h, filter, wash, and vacuum dry to obtain spherical PCN-224. (2) Preparation of Bi NPs / PCN-224: Using ethylene glycol and deionized water as solvents, PCN-224 and Bi(NO3)3·5H2O as raw materials, polyvinyl pyrrolidone as surfactant, and sodium borohydride as reducing agent, the in situ precipitation method was used to mix and react at room temperature for 1-4 h, followed by centrifugal washing and vacuum drying to obtain Bi NPs / PCN-224 binary composite materials.

2. The method for preparing the binary nanocomposite material Bi NPs / PCN-224 according to claim 1, characterized in that: In step (1), the mass ratio of ZrOCl2·8H2O to TCPP is 1:2-1:

5.

3. The method for preparing the binary nanocomposite material Bi NPs / PCN-224 according to claim 1, characterized in that: In step (1), the mass ratio of benzoic acid to TCPP is 1:3 to 1:

4.

4. The method for preparing the binary nanocomposite material Bi NPs / PCN-224 according to claim 1, characterized in that: In step (2), the mass ratio of PCN-224 to Bi(NO3)3·5H2O is 1:2 to 1:

3.

5. The method for preparing the binary nanocomposite material Bi NPs / PCN-224 according to claim 1, characterized in that: In step (2), the mass ratio of NaBH4 to Bi(NO3)3·5H2O is 1:1~1:

2.

6. The method for preparing the binary nanocomposite material Bi NPs / PCN-224 according to claim 1, characterized in that: In step (2), the mass ratio of Bi(NO3)3·5H2O to polyvinyl pyrrolidone is 3:1~1:

1.

7. Use of the binary nanocomposite material prepared by the method according to claim 1 in photocatalytic antibacterial.

8. The use of the binary nanocomposite material in photocatalytic antibacterial as claimed in claim 7, characterized in that: The bacteria subjected to the photocatalytic antibacterial effect of the binary nanocomposite material are at least one of Staphylococcus aureus, Escherichia coli and drug-resistant bacteria.

9. Use of the binary nanocomposite material prepared by the method of claim 1 in the preparation of anticancer drugs.

10. Use of the binary nanocomposite material according to claim 9 in the preparation of anticancer drugs, characterized in that: The anticancer drug is an anti-liver cancer drug; The liver cancer cells were HepG2 cells.

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