Preparation method of platinum-doped hollow gold nanorod with high photo-thermal stability

Abstract

The invention relates to a preparation method of a platinum-doped hollow gold nanorod with high photo-thermal stability. The invention belongs to the technical field of nano material preparation. The preparation method comprises the following steps: adding a tellurium precursor substance and a selenium precursor substance into a hydrazine hydrate-containing solution, continuously magnetically stirring, and diluting by using an aqueous solution of lauryl sodium sulfate after the reaction is completed, so as to obtain the tellurium-selenium nanorod; and dispersing the prepared tellurium-selenium nanorod in pure water, adding a gold precursor, a platinum precursor and a modifier at the same time, and then performing centrifugal separation to obtain the platinum-doped hollow gold nanorod. The thermal stability of the hollow gold nanorod is effectively improved through platinum doping, and when the platinum doping proportion is 10% or above, the light and heat stability of the hollow gold nanorod is obviously improved; the positive significance is realized on the full play of the effect of the material in photo-thermal therapy and related combined therapy application.

Description

Technical Field

[0001] The invention relates to a method for preparing platinum-doped hollow gold nanorods with high light and heat stability, and belongs to the technical field of nano material preparation. Background Art

[0002] The ripening of gold nanomaterials in solution causes changes in their morphology, with higher temperatures resulting in faster ripening. The optical properties of gold nanomaterials are closely related to their morphology, size, and structure. For example, the plasmon absorption peak of gold nanorods undergoes a significant red shift as their aspect ratio increases. When their aspect ratio reaches approximately 6, the absorption peak can be tuned to the near-infrared region II window (1000 nm). For hollow gold nanorods, the absorption peak can be shifted to the near-infrared region II range when the aspect ratio reaches approximately 3 (ACS Appl. Mater. Interfaces, 2018, 10, 36703). The near-infrared region II window is more suitable for biomedical applications than the traditional near-infrared region I window because near-infrared region II light sources have a stronger ability to penetrate biological tissue and have a higher maximum permissible radiation dose for use in living organisms. Therefore, photothermal therapy and photoacoustic imaging using near-infrared region II light sources can be performed at greater depths in biological tissue. However, during the photothermal application process, the heat generated by the hollow gold nanorods will cause their own and surrounding environment temperatures to rise, accelerating their ripening, resulting in morphological destruction and a reduction in photothermal conversion properties, which is very unfavorable for applications based on their photothermal conversion properties.

[0003] In addition, hollow gold nanorods are also an effective nanocarrier for combined therapy. Studies have shown that combined therapy is a method of combining two or more methods such as chemotherapy, photothermal therapy, photodynamic therapy or immunotherapy, and they are more effective in treating tumors than single treatment methods. Compared with solid nanorods, the hollow structure of hollow gold nanorods has a certain load capacity, and the uneven surface structure increases the specific surface area, which is very beneficial for modifying or loading chemotherapy or photodynamic therapy drugs. Therefore, hollow gold nanorods have greater potential as a comprehensive diagnostic and therapeutic nanoplatform in combined therapy than solid gold nanorods. Hollow gold nanorods are one of the few gold nanomaterials that can adjust the plasmon absorption peak to the near-infrared second window. In order to give full play to their effects in photothermal therapy and related combined therapy applications, it is necessary to improve the photothermal stability of hollow gold nanorods. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing platinum-doped hollow gold nanorods with high photothermal stability in view of the above-mentioned shortcomings or deficiencies of the prior art.

[0005] The technical solution of the present invention is: A method for preparing platinum-doped hollow gold nanorods with high photothermal stability, characterized in that it comprises the following steps: (a) adding a tellurium precursor and a selenium precursor to a solution containing hydrazine hydrate and continuously stirring under magnetic force, wherein the tellurium precursor is tellurium dioxide or tellurious acid, and the selenium precursor is selenious acid, in a molar ratio of 40:1 to 100:1; reacting at a temperature of 30 to 40° C. for 20 minutes, followed by dilution with an aqueous solution of sodium dodecyl sulfate, and then performing solid-liquid separation to obtain a precipitate to obtain tellurium selenide nanorods; (b) dispersing the tellurium selenide nanorods prepared in step (a) in a 1.0-3.0 μmol / L cysteine ​​aqueous solution, and then simultaneously adding a gold precursor and a platinum precursor to the solution, wherein the gold precursor is chloroauric acid and the platinum precursor is chloroplatinic acid or chloroplatinate; magnetic stirring is performed for a preset reaction time, and centrifugation is performed to obtain platinum-doped hollow gold nanorods.

[0006] In step (b), the molar ratio of the platinum precursor to the gold and platinum noble metals is 10% to 20%; the reaction temperature of the noble metal precursor in the cysteine ​​aqueous solution is 10 to 30°C.

[0007] In step (b), the platinum-doped hollow gold nanorods include a shell and a hollow region formed by covering the shell.

[0008] The beneficial effects of the present invention compared with the prior art are: The present invention effectively improves the thermal stability of hollow gold nanorods by platinum doping, and when the platinum doping ratio is 10% or above, the improvement in the photothermal stability of the hollow gold nanorods is very obvious; this has positive significance for fully exerting its effect in photothermal therapy and related combined treatment applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The absorption spectra of hollow gold nanorods not doped with platinum after irradiation with lasers of different powers; Figure 2 TEM image of hollow gold nanorods without platinum doping; Figure 3 The ratio of the absorbance of the hollow gold nanorods with different platinum doping contents after irradiation with lasers of different powers to the absorbance before irradiation is changed; Figure 4 TEM image of the hollow gold nanorods doped with 20% platinum according to the present invention; Figure 5 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0010] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0011] The preparation method of the platinum-doped hollow gold nanorods with high photothermal stability is as follows: (a) adding a tellurium precursor and a selenium precursor to a solution containing hydrazine hydrate and continuously stirring under magnetic force, wherein the tellurium precursor is tellurium dioxide or tellurious acid, and the selenium precursor is selenious acid, in a molar ratio of 40:1 to 100:1; reacting at a temperature of 30 to 40° C. for 20 minutes, followed by dilution with an aqueous solution of sodium dodecyl sulfate, and then performing solid-liquid separation to obtain a precipitate to obtain tellurium selenide nanorods; (b) dispersing the tellurium selenide nanorods prepared in step (a) in 1.0-3.0 μmol / L cysteine, and then adding a gold precursor and a platinum precursor to the solution simultaneously, wherein the gold precursor is chloroauric acid and the platinum precursor is chloroplatinic acid or chloroplatinate; magnetic stirring is performed for a preset reaction time, and centrifugation is performed to obtain platinum-doped hollow gold nanorods.

[0012] In step (b), the molar ratio of the platinum precursor to the gold and platinum noble metals is 10% to 20%; the reaction temperature of the platinum precursor and the gold precursor in the cysteine ​​solution is 10 to 30°C.

[0013] In step (b), the platinum-doped hollow gold nanorods include a shell and a hollow region formed by covering the shell.

[0014] The present invention will be further described below with reference to specific embodiments. Example 1

[0015] (a) Tellurium dioxide and selenious acid were added to a hydrazine hydrate solution at a molar ratio of 100:1, and the mixture was stirred at 40°C. After 20 minutes of reaction, the reaction solution was transferred to a solution containing sodium dodecyl sulfate, stirred for 10 minutes, and then centrifuged to obtain a precipitate to obtain tellurium selenide nanorods. (b) The tellurium selenide nanorods prepared in step (a) were dispersed in a 3.0 μmol / L cysteine ​​aqueous solution and magnetically stirred at 30°C. A solution of chloroauric acid and chloroplatinic acid was then added, wherein the molar ratio of chloroauric acid to chloroplatinic acid was 9:1. The mixture was stirred for 10 minutes and centrifuged to obtain platinum-doped hollow gold nanorods. Example 2

[0016] (a) Tellurious acid and selenious acid were added to a hydrazine hydrate solution and stirred at 35°C for reaction, wherein the molar ratio of tellurious acid to selenious acid was 40:1. After 20 minutes of reaction, the reaction solution was transferred to a solution containing sodium dodecyl sulfate, stirred for 10 minutes, and then centrifuged to obtain a precipitate to prepare tellurium selenide nanorods; (b) Dispersing the tellurium selenide nanorods prepared in step (a) in a 1.0 μmol / L cysteine ​​aqueous solution, magnetically stirring at 20° C., then adding chloroauric acid and chloroplatinic acid solutions, wherein the molar ratio of chloroauric acid to chloroplatinic acid is 4:1, stirring for 15 minutes, and centrifuging to obtain platinum-doped hollow gold nanorods. Example 3

[0017] (a) Tellurium dioxide and selenious acid were added to a hydrazine hydrate solution at a molar ratio of 100:1, and the mixture was stirred at 40°C for 20 minutes. The reaction solution was then transferred to a solution containing sodium dodecyl sulfate, stirred for 10 minutes, and centrifuged to obtain a precipitate, thereby obtaining tellurium selenide nanorods. (b) Dispersing the tellurium selenide nanorods prepared in step (a) in a 2.0 μmol / L cysteine ​​aqueous solution, magnetically stirring at 25°C, then adding chloroauric acid and chloroplatinic acid solutions, wherein the molar ratio of chloroauric acid to chloroplatinic acid is 19:1, stirring for 10 minutes, and centrifuging to obtain platinum-doped hollow gold nanorods. Example 4

[0018] (a) Tellurium dioxide and selenious acid were added to a hydrazine hydrate solution at a molar ratio of 100:1, and the mixture was stirred at 40°C for 20 minutes. The reaction solution was then transferred to a solution containing sodium dodecyl sulfate, stirred for 10 minutes, and centrifuged to obtain a precipitate, thereby obtaining tellurium selenide nanorods. (b) Dispersing the tellurium selenide nanorods prepared in step (a) in a 2.0 μmol / L cysteine ​​aqueous solution, magnetically stirring at 20°C, then adding chloroauric acid and chloroplatinic acid solutions, wherein the molar ratio of chloroauric acid to chloroplatinic acid is 17:3, stirring for 10 minutes, and centrifuging to obtain platinum-doped hollow gold nanorods.

[0019] Example 5 (Comparative Example) (a) adding tellurious acid and selenious acid to a hydrazine hydrate solution and stirring the mixture at 35°C, wherein the molar ratio of tellurious acid to selenious acid is 80:1. After reacting for 20 minutes, the reaction solution is transferred to a solution containing sodium dodecyl sulfate, stirred for 10 minutes, and then centrifuged to obtain a precipitate, thereby preparing tellurium selenide nanorods; (b) The tellurium selenide nanorods prepared in step (a) were dispersed in a 2.0 μmol / L cysteine ​​aqueous solution and magnetically stirred at 25°C. A chloroauric acid solution was then added and stirred for 10 min. The mixture was centrifuged to obtain platinum-free hollow gold nanorods.

[0020] In order to verify the thermal stability of the platinum-doped hollow gold nanorods prepared by the present invention, the inventors used 1064 nm laser, which is commonly used in near-infrared region II research, as the test condition and tested the spectra of the undoped hollow gold nanorods after irradiation with different laser powers (see Figure 1 ), Figure 2 TEM image of hollow gold nanorods. Figure 1 It can be seen that as the laser power increases, the greater the wavelength difference of the blue shift of the hollow gold nanorod plasma absorption peak position, the greater the decrease in absorbance at the 1064 nm position. After 2.48W laser irradiation, the absorbance at 1064 nm decreased by nearly 50% compared to before irradiation. For better comparison, the inventors prepared platinum-doped hollow gold nanorods under the conditions that the molar ratio of platinum precursor to gold and platinum precious metal was 5%, 10%, 15% and 20%, respectively. The hollow gold nanorods prepared under four different platinum doping conditions were then subjected to photothermal testing. The ratio of their absorbance after irradiation with lasers of different powers to the absorbance before irradiation was statistically analyzed and compared with undoped hollow gold nanorods (see Figure 3 The results showed that only the 5% platinum-doped hollow gold nanorods showed a significant decrease in absorbance. After 1.82 W laser irradiation, the decrease exceeded 10%, and after 2.48 W laser irradiation, the decrease exceeded 20%. The decreases of the other three hollow gold nanorods were all less than 10%. The smaller the decrease, the higher the thermal stability of the material. The highest was the hollow gold nanorod with a platinum precursor doping dosage of 20%. Figure 4 This is a TEM image of platinum-doped hollow gold nanorods. Although the absorbance of the 5% Pt-doped hollow gold nanorods decreased significantly, the magnitude of this decrease was less than half that of the undoped hollow gold nanorods. In summary, improving the stability of hollow gold nanorods by Pt-doping is effective and feasible.

Claims

1. A method for preparing platinum-doped hollow gold nanorods with high photothermal stability, characterized in that: It includes the following steps: (a) adding a tellurium precursor and a selenium precursor to a solution containing hydrazine hydrate and continuously stirring under magnetic force, wherein the tellurium precursor is tellurium dioxide or tellurious acid, and the selenium precursor is selenious acid, in a molar ratio of 40:1 to 100:1; reacting at a temperature of 30 to 40° C. for 20 minutes, then diluting with an aqueous solution of sodium dodecyl sulfate, and performing solid-liquid separation to obtain a precipitate to obtain tellurium selenide nanorods; (b) dispersing the tellurium selenide nanorods prepared in step (a) in 1.0-3.0 μmol / L cysteine, and then adding a gold precursor and a platinum precursor to the solution simultaneously, wherein the gold precursor is chloroauric acid and the platinum precursor is chloroplatinic acid or chloroplatinate; magnetic stirring is performed for a preset reaction time, and centrifugation is performed to obtain platinum-doped hollow gold nanorods.

2. The method for preparing platinum-doped hollow gold nanorods with high photothermal stability according to claim 1, characterized in that: In step (b), the molar ratio of the platinum precursor to the gold and platinum noble metals is 10% to 20%; the reaction temperature of the platinum precursor and the gold precursor in the cysteine ​​solution is 10 to 30°C.

3. The method for preparing platinum-doped hollow gold nanorods with high photothermal stability according to claim 1, characterized in that: In step (b), the platinum-doped hollow gold nanorods include a shell and a hollow region formed by covering the shell.

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