Preparation of TiO2 core Ag satellite hybrid super nanostructure and SERS detection application of sisomicin

Abstract

The invention discloses preparation of a TiO2 core Ag satellite hybrid super nanostructure and application to SERS (Surface Enhanced Raman Scattering) detection of sisomicin, and relates to the field of analytic detection.The TiO2 core Ag satellite hybrid super nanostructure is synthesized by modifying the surfaces of TiO2 microspheres, adsorbing Ag nano-particles through static electricity and can be used as an SERS substrate to detect sisomicin, and through a charge transfer mechanism between cores and satellites, the SERS detection of the sisomicin can be realized. The detection sensitivity of sisomicin is greatly improved. Under the optimal experimental conditions, the linear detection range of sisomicin is 10 <-5 >-10 <-11 > M, the detection limit is 7.12 * 10 <-12 > M, and the relative standard deviation of SERS intensity is less than 10%; the method is simple and convenient to operate and high in accuracy and sensitivity, does not need a complicated operation technology, and meets the requirements of large-batch and rapid analysis and detection.

Description

Technical Field

[0001] The present invention relates to the field of analysis and detection, and in particular to the preparation of a TiO2 core-Ag satellite hybrid super nanostructure and the SERS detection application of sisomicin. Background Art

[0002] Sisomicin is an important water-soluble aminoglycoside antibiotic clinically used to treat local or systemic infections caused by Gram-negative bacteria. However, sisomicin can cause strong ototoxicity and nephrotoxicity. Improper use may lead to allergic reactions and drug resistance in some pathogens. Therefore, it is crucial to monitor the dose of sisomicin to ensure its therapeutic effect while minimizing side effects.

[0003] Currently, there are limited methods for the detection of sisomicin, and most of the available methods are high performance liquid chromatography (HPLC), which is generally equipped with detectors such as UV-visible light, fluorescence, and resonance Rayleigh scattering. Because it lacks a chromophore, sisomicin must be treated with a derivatization reagent (1-fluoro-2,4-dinitrobenzene or o-phthalaldehyde) for these research methods. In addition, by-products are inevitably produced during the derivatization process. For resonance Rayleigh scattering and evaporative light scattering detectors, their sensitivity and selectivity are not satisfactory. Therefore, there is an urgent need to establish a convenient and sensitive sisomicin detection technology. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems in the prior art and provide a simple, rapid and reliable SERS (surface enhanced Raman scattering) detection method for sisomicin, which uses a TiO2 core Ag satellite hybrid super nanostructure as a SERS substrate to quantitatively analyze sisomicin. Under the conditions of optimizing the binding amount ratio, optimal detection time and pH, quantitative analysis of sisomicin is achieved. The linear detection range of sisomicin is 10 -5 ~10 -11 M, detection limit is 7.12×10 -12 M, the relative standard deviation of SERS intensity is less than 10%. TiO2 core Ag satellite hybrid super nanostructure as SERS substrate has the advantages of simple operation, high accuracy and sensitivity, and no need for complex operation technology. It can be widely used in practical detection of antibiotics in SERS detection.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A TiO2 core-Ag satellite hybrid super nanostructured sisomicin SERS detection application comprises the following steps:

[0007] 1) Preparation of silver nanoparticle sol;

[0008] 2) Amino modification of TiO2 nanoparticles;

[0009] 3) Mixing the amino-modified TiO2 with silver nanoparticle sol to obtain a TiO2 core-Ag satellite hybrid super nanostructure, which is used as a SERS substrate;

[0010] 4) The sisomicin sample solution is mixed with the SERS substrate to perform surface enhanced Raman detection on sisomicin.

[0011] In step 1), the silver nanoparticle sol is prepared by sodium citrate reduction method.

[0012] In step 2), TiO2 nanoparticles are dispersed in water, and then ammonia water and aminopropyltriethoxysilane are added under stirring in a water bath for amino modification.

[0013] In step 4), the pH value of the mixed solution of the sisomicin sample solution and the SERS substrate is 3-5.

[0014] In step 4), the test is performed within 0.5 min after mixing.

[0015] In step 4), at the optimal excitation wavelength, as the concentration of the sample solution increases, the Raman peak of the sample to be tested at a specific wavelength gradually increases. A standard curve is established using the relationship between the intensity of the Raman characteristic peak of the sample to be tested and the amount of the sample to be tested, and the sample to be tested is quantitatively analyzed and detected.

[0016] The optimal excitation wavelength refers to an excitation wavelength of 785 nm.

[0017] In the present invention, the Raman peak of sisomicin at a specific wavelength refers to the peak of sisomicin at 932 cm -1 The characteristic Raman peak at .

[0018] In the present invention, the linear detection range of sisomicin is 10 -5 ~10 -11 M, detection limit is 7.12×10 -12 M.

[0019] The relative standard deviation of the SERS intensity of the present invention is less than 10%.

[0020] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0021] The present invention uses electrostatic adsorption to prepare TiO2 core Ag satellites as SERS substrates. The SERS substrate not only has excellent SERS Raman enhancement effect, but also has excellent sensitivity. At the same time, the SERS substrate preparation process is simple, low-cost, highly repeatable, has excellent detection sensitivity, and the detection method is simple and easy to operate. Sisomicin was selected as the target molecule, and the Raman enhancement effect of TiO2 core Ag satellite nanoparticles on sisomicin was tested by adjusting parameters such as pH. The experimental results show that the TiO2 core Ag satellite has an excellent Raman enhancement effect as a SERS substrate. By utilizing the linear relationship between the signal intensity and concentration of the sample solution at the characteristic Raman peak, a simple and rapid analysis method is established without the need for complex specific modification, and the SERS characteristic peak of the sample solution is directly used for quantitative analysis. The linear detection range of sisomicin in the present invention is 10 -5 ~10 -11 M, detection limit is 7.12×10 -12 The relative standard deviations of SERS intensities are all less than 10%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 SEM image of Ag satellite in the TiO2 core.

[0023] Figure 2 A in the middle is the SERS spectra of the TiO2 core Ag satellite and sisomicin solution at different volume ratios; Figure 2 B in the figure is the SERS spectrum of sisomicin measured under different pH conditions.

[0024] Figure 3 SERS spectra of TiO2 core Ag satellite and sisomicin solution under different mixing time conditions.

[0025] Figure 4 A in the figure shows sisomicin measured ten times in parallel (10 -5 M) SERS spectrum; Figure 4 B in the figure shows sisomicin measured ten times in parallel (10 -5 M) at 932 cm -1 Histogram of SERS peak intensity at .

[0026] Figure 5 A in the figure is the SERS spectra of sisomicin at different concentrations, where the concentrations from top to bottom are (a) 10 -5 M (b) 10 -6 M (c) 10 -7 M (d) 10 -8 M (e) 10 -9 M(f) 10 -10 M(g) 10 -11M; Figure 5 B in the middle is sisomicin at 932cm -1 The relationship between the SERS intensity at and the negative logarithm of the concentration.

[0027] Figure 6 The SERS spectra of different aminoglycoside antibiotic solutions, where, from top to bottom a→h are (a) sisomicin (b) neomycin (c) tobramycin (d) streptomycin (e) gentamicin (f) kanamycin (g) netilmicin (h) acamycin. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0029] The present invention comprises the following steps:

[0030] 1) Preparation of silver nanoparticle sol (silver sol) by sodium citrate reduction method;

[0031] 2) Preparation of TiO2 core-Ag satellite hybrid super nanostructures;

[0032] 3) Determine the best sample detection conditions. Under the optimal excitation wavelength, optimize the sample solution and SERS substrate according to the optimal binding ratio, optimize the mixing time of the sample solution and SERS substrate, optimize the pH conditions of the detection, and determine the best sample detection conditions.

[0033] 4) Quantitative analysis and detection of sample solution on SERS substrate. As the concentration of sample solution increases, the Raman peak of the sample to be tested at a specific wavelength gradually increases. The relationship between the intensity of the Raman characteristic peak of the sample to be tested and the amount of the sample to be tested is used to establish a standard curve to perform quantitative analysis and detection on the sample to be tested.

[0034] In step 1), take the AgNO3 solution in a flask, stir and heat to boiling reflux state, add sodium citrate until the solution becomes a slightly green opaque liquid, continue heating and reflux for 50 to 60 minutes, stop heating, cool naturally to room temperature, seal and store in a dark place. The mass percentage concentration of the sodium citrate is 0.8% to 1.5%, the volume ratio of sodium citrate to silver nitrate is 30 to 50; the concentration of the silver nitrate solution is 1 to 3 mmol / L; the reaction temperature is 90 to 100 °C.

[0035] In step 2), TiO2 nanoparticles are dispersed in ultrapure water, stirred in a water bath for 5 to 6 minutes, and ammonia water and aminopropyl triethoxysilane are added, and the water bath is continued and stirred fully. Cool to room temperature, centrifuge and ultrasonicate for 20 to 30 minutes, and wash three times with deionized water. The amino-modified TiO2 is mixed with silver sol and stirred for 2 to 3 hours to obtain the TiO2 core Ag satellite. The TiO2 nanoparticles are 0.8 to 1g, the dispersed ultrapure water is 800 to 1000ml, the mass fraction of ammonia water added is 25%, and the volume is 0.25 to 0.32ml. The aminopropyl triethoxysilane is 0.8 to 1ml.

[0036] In step 2), the volume ratio of the silver sol to the TiO2 solution is 25:1.

[0037] In step 3), the optimal binding ratio is to control the concentration of the TiO2 core Ag satellite to be the synthetic stock solution concentration and the concentration of the sample solution to be 10 -5 M, the volume ratio of the TiO2 core Ag satellite to the sample solution is 1:0.5. The optimal pH condition is to adjust the pH value of the mixed solution of the TiO2 core Ag satellite and the sample solution to 3-5, wherein sisomicin is adjusted with HNO3. The sample solution refers to a sample solution prepared with water as a solvent. The optimal excitation wavelength refers to an excitation wavelength of 785 nm. The optimal detection time refers to detection within 0.5 min after all substances are mixed.

[0038] In step 4), the Raman peak of sisomicin at a specific wavelength refers to the Raman peak of sisomicin at 932 cm -1 The standard curve is established under the optimal experimental conditions, with the logarithmic value of the series concentration of the sample solution as the horizontal axis and the peak intensity of the sample solution at the strongest characteristic peak as the vertical axis; the linear detection range of sisomicin is 10 -5 ~10 -11 M, detection limit is 7.12×10 -12 M, the relative standard deviation of SERS intensity is less than 10%.

[0039] Specific examples are given below.

[0040] 1. Synthesis of Ag satellite in TiO2 core

[0041] Synthesize Ag nanoparticles with a particle size of about 50 ± 10 nm: prepare a 1% sodium citrate aqueous solution in advance, prepare a 1 mmol / L AgNO3 solution, take 100 mL of the prepared AgNO3 solution in a single-mouth round-bottom flask, stir with a magnetic stirrer, and heat to boiling reflux with an electric heating mantle (reaction temperature is 90-100 °C, stirring speed is 1000-1500 r / min), add 3 mL of the pre-prepared 1% sodium citrate aqueous solution, about 1 minute after addition, the solution changes from colorless to milky white, and then to a slightly green opaque liquid. Continue stirring and heating to a slight boil for 50-60 min, then remove the heating mantle to stop heating, cool naturally to room temperature, and then cover the round-bottom flask with aluminum foil to seal and store away from light.

[0042] For TiO2 modification, 0.8g TiO2 nanodispersed in 800ml ultrapure water, stirred in a water bath at 80℃ for 5-6min, added 0.25ml 25% ammonia water and 0.8ml aminopropyltriethoxysilane, continued to be water bathed and stirred for 6-7h. Cooled to room temperature, centrifuged and ultrasonicated for 30min, washed three times with deionized water. The amino-modified TiO2 was mixed with silver sol and stirred for 2-3h to obtain the TiO2 core Ag satellite.

[0043] The particle size of the prepared TiO2 core Ag satellite is about 200 ± 10 nm. The particle size and shape of the core-shell nanoparticles were characterized by scanning electron microscopy (SEM) (see Figure 1 ).

[0044] 2. Optimal ratio of TiO2 core Ag satellite to sisomicin solution

[0045] The concentration of Ag satellite in TiO2 core was fixed to the original solution concentration, and the concentration of sisomicin solution was 10 -5 M, the volume ratio of TiO2 core Ag satellite and sisomicin solution was adjusted to 1:0.25, 1:0.5, 1:0.75, 1:1, 1:1.25, and SERS spectra were collected. Figure 2 In Figure A, it can be seen that when the volume ratio of the TiO2 core Ag satellite to the sisomicin solution reaches 1:0.5, the SERS intensity of sisomicin reaches the strongest. Therefore, in subsequent experiments, the volume ratio of the TiO2 core Ag satellite to the sisomicin solution is fixed at 1:0.5.

[0046] 3. Optimal detection time of Ag satellite and sisomicin in TiO2 core

[0047] The concentration of Ag satellite in TiO2 core was fixed to the original solution concentration, and the concentration of sisomicin solution was 10 -5M, adjust the mixing time of TiO2 core Ag satellite and sisomicin solution to 0.5min, 2.5min, 4.5min, 6.5min, 8.5min, 10.5min. Scan the surface enhanced Raman spectrum of sisomicin to determine the optimal mixing time. Figure 3 , it can be seen that when the mixing time of TiO2 core Ag satellite and sisomicin is 0.5min, the SERS intensity of sisomicin reaches the strongest.

[0048] 4. Optimal pH of TiO2 core Ag satellite and sisomicin solution

[0049] The volume ratio of TiO2 core Ag satellite and sisomicin solution was fixed at 1:0.5, and the pH of the mixed solution of TiO2 core Ag satellite and sisomicin solution was adjusted to 3, 5, 7, 9, and 11, respectively. The surface enhanced Raman spectrum of sisomicin was scanned to determine the optimal pH.

[0050] Figure 2 B is the SERS spectra of sisomicin measured under different pH conditions. It can be seen from the figure that when pH=5, the intensity of the surface enhanced Raman signal peak of sisomicin is the strongest, so the optimal pH value of the detection system of sisomicin is 5.

[0051] 5. Uniformity of SERS substrate of sisomicin

[0052] Take the TiO2 core Ag satellite and the concentration as 10 -5 The volume ratio of sisomicin solution was fixed at 1:0.5, the pH was adjusted to 5, the mixing time was 0.5 min, and the SERS spectra were randomly collected ten times on the substrate with an excitation wavelength of 785 nm. The SERS peak intensities of sisomicin collected ten times in parallel were compared to determine the uniformity of the SERS substrate.

[0053] Figure 4 A in the middle is the SERS spectrum of sisomicin measured ten times in parallel. Figure 4 B is ten parallel measurements of sisomicin at 932 cm -1 From the histogram of SERS peak intensity at 932 cm, we can see that the relative standard deviation (RSD) of the SERS characteristic peak intensity calculated for 10 sets of parallel samples is -1 The SERS substrate has good uniformity and can be applied to the quantitative analysis of surface-enhanced Raman spectroscopy of sisomicin.

[0054] 6. SERS detection of sisomicin

[0055] Take TiO2 core Ag satellite and sisomicin solutions of different concentrations, fix their volume ratio at 1:0.5, control the pH at 5, mix for 0.5 min, collect SERS spectra under excitation at 785 nm excitation light wavelength, and measure SERS spectra of sisomicin of different concentrations.

[0056] Figure 5 A in the figure is the SERS spectra of sisomicin at different concentrations, where the concentrations of a→g from top to bottom are 10 -5 M, 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M, 10 -10 M, 10 -11 M, it can be seen that with the increase of concentration, the surface enhanced Raman peak intensity of sisomicin becomes stronger.

[0057] Figure 5 B is the standard curve established after testing different concentrations of sisomicin standard solutions. -5 ~10 -11 M range, sisomicin 932cm -1 The intensity of the characteristic peak has a negative logarithmic relationship with the concentration of sisomicin, showing a positive correlation (y = 1559.5 x + 19804), R 2 = 0.9945, and the limit of detection (LOD) is 7.12 × 10 -12 M.

[0058] 7. Selectivity of TiO2 core Ag satellite for sisomicin, neomycin, tobramycin, streptomycin, gentamicin, kanamycin, netilmicin, and acamycin

[0059] Take the TiO2 core Ag satellite with a concentration of 10 -5 The volume ratio of sisomicin, neomycin, tobramycin, streptomycin, gentamicin, kanamycin, netilmicin and akamicin was fixed at 0.6-0.7, the pH value was adjusted to 4-6, and the surface enhanced Raman spectra of sisomicin, neomycin, tobramycin, streptomycin, gentamicin, kanamycin, netilmicin and akamicin were obtained at an excitation wavelength of 785 nm.

[0060] Figure 6The SERS spectra of different aminoglycoside antibiotics sisomicin, neomycin, tobramycin, streptomycin, gentamicin, kanamycin, netilmicin, and akamycin solutions are shown in Figure 1. From top to bottom, from a→h, they are (a) sisomicin (b) neomycin (c) tobramycin (d) streptomycin (e) gentamicin (f) kanamycin (g) netilmicin (h) akamycin. It can be seen from the figure that under acidic conditions, the eight antibiotics can be divided into three categories according to the peak shape, namely akamycin; streptomycin, gentamicin, kanamycin, netilmicin; sisomicin, neomycin, and tobramycin. There is no characteristic peak for akamycin; for streptomycin, gentamicin, kanamycin, and netilmicin, streptomycin and gentamicin have peaks at 932 cm -1 The peak at 785 cm -1 、932cm -1 and 1396cm -1 The peak at 1089 cm -1 The peak intensity is the strongest at 785 cm-1, and neomycin and tobramycin are at 785 cm-1. -1 Therefore, under acidic conditions (pH = 5), the TiO2 core Ag satellite can be used as a SERS substrate to distinguish sisomicin, neomycin, tobramycin, streptomycin, gentamicin, kanamycin, netilmicin, and acamycin.

[0061] The present invention uses TiO2 core Ag satellite nanoparticles as SERS substrates, adsorbs sisomicin in the SERS enhancement region of the aggregates of TiO2 core Ag satellite nanoparticles through electrostatic action, enhances and amplifies the SERS signal of sisomicin, and performs quantitative analysis on sisomicin. Under the conditions of optimizing the binding amount ratio and pH, quantitative analysis of sisomicin is achieved. The linear detection range of sisomicin is 10 -5 ~10 -11 M, the detection limit was 7.12 × 10 -12 M, the relative standard deviation of SERS intensity is less than 10%. TiO2 core Ag satellite as SERS substrate has the advantages of low cost, controllability, high detection efficiency, etc., and can be widely used in practical detection in SERS detection of antibiotics. In addition, this method is easy to operate, has high accuracy and sensitivity, does not require complex operating techniques, and can meet the requirements of large-scale and rapid analysis and detection.

Claims

1. A TiO2 core-Ag satellite hybrid super nanostructure for sisomicin SERS detection, characterized in that: The following steps are involved: 1) Preparation of silver nanoparticle sol; 2) Amino modification of TiO2 nanoparticles; 3) Mixing the amino-modified TiO2 with silver nanoparticle sol to obtain a TiO2 core-Ag satellite hybrid super nanostructure, which is used as a SERS substrate; 4) The sisomicin sample solution is mixed with the SERS substrate to perform surface enhanced Raman detection on sisomicin.

2. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure according to claim 1, characterized in that: In step 1), the silver nanoparticle sol is prepared by sodium citrate reduction method.

3. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure as claimed in claim 1, characterized in that: In step 2), TiO2 nanoparticles are dispersed in water, and then ammonia water and aminopropyltriethoxysilane are added under stirring in a water bath for amino modification.

4. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure according to claim 1, characterized in that: In step 4), the pH value of the mixed solution of the sisomicin sample solution and the SERS substrate is 3-5.

5. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure as claimed in claim 1, characterized in that: In step 4), the test is performed within 0.5 min after mixing.

6. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure according to claim 1, characterized in that: In step 4), at the optimal excitation wavelength, as the concentration of the sample solution increases, the Raman peak of the sample to be tested at a specific wavelength gradually increases. A standard curve is established using the relationship between the intensity of the Raman characteristic peak of the sample to be tested and the amount of the sample to be tested, and the sample to be tested is quantitatively analyzed and detected.

7. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure as claimed in claim 6, characterized in that: The optimal excitation wavelength refers to an excitation wavelength of 785 nm.

8. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure as claimed in claim 6, characterized in that: The Raman peak of sisomicin at a specific wavelength refers to the peak of sisomicin at 932 cm -1 The characteristic Raman peak at .

9. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure as claimed in claim 1, characterized in that: The linear detection range of sisomicin is 10 -5 ~10 -11 M, detection limit is 7.12×10 -12 M.

10. The SERS detection application of sisomicin of the TiO2 core-Ag satellite hybrid super nanostructure according to claim 1, characterized in that: The relative standard deviation of SERS intensity is less than 10%.

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