AU2018100220A4

AU2018100220A4 - A PtCu oxidase mimic with nanoflower structure

Info

Publication number: AU2018100220A4
Application number: AU2018100220A
Authority: AU
Inventors: Mingji Li; Boyuan Xiao; Ziqian Xu
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-02-20
Filing date: 2018-02-20
Publication date: 2018-03-22
Anticipated expiration: 2026-02-20

Abstract

The present invention discloses a one-pot synthesis method for the preparation of PtCu nanoparticles in aqueous solution. According to the Transmission Electronic Microscopy (TEM) image, the observed PtCu nanoparticles have nanoflower structure and with an average size less than 20 nm. The prepared PtCu nanoparticles with a Pt/Cu feeding molar ratio of 3:1 show the highest oxidase-like activity. The influence of temperature, pH value, and the concentration of TMB substrate on the oxidase catalytic activity of PtCu nanoparticles were also studied in this patent. According to the result, the optimum reaction temperature is 30 - 60 'C, the optimal pH value of the reaction buffer is at 3.0 and the optimal concentration of 3,3',5,5' tetramethylbenzidine (TMB) is at 0.4 mM.

Description

DESCRIPTION

TITLE A PtCu oxidase mimic with nanoflower structure

FIELD OF THE INVENTION

The present invention relates to synthesis of PtCu nanoenzyme, which has significant in chemical, catalytical, biosensing, industrial and environmental fields.

BACKGROUND OF THE INVENTION

Enzymes not only play the crucial roles in living activities, but also have profound influence in environmental science and industrial fields. However, natural enzymes have distinct defects since they cannot stand high temperature or strong acid/base condition. In addition, due to their few amounts in living creatures, it is costly to prepare for quantitative analysis, as well as purification.

With the development of nanoscience, researchers have found that some nanomaterials have enzyme-like activities. Compared to natural enzymes, these nanoenzymes have better stability under extreme conditions, better biocompatibility as well as high catalytic activities.1 Furthermore, nanoenzymes are cost-effective and convenient for mass production. Thus, nanoenzymes can be applied both in scientific fields and industrial fields. Over the past decade, several types of nanoenzymes have been reported. The first type is called Iron-Based nanoenzymes, which uses Iron (II, III) oxide, Fe304 or Iron (III) oxide, Fe203 to serve as the body of catalyst.2 The second type is called non-iron Metallic nanoenzymes, which uses non-iron metal oxides nanomaterials or multi-metal nanocomposites such as PtAu or AgAu to improve reaction rate. The third type is called non-Matallic nanoenzymes, which uses carbon-based nanomaterials or other non-metal nanomaterials to lower activation energy. In recent studies, researchers have found that bimetallic nanoenzymes have better stability and higher catalytic activity compared to monometallic nanoenzymes. As reported, PtCo3, PtAg4 and PdAg5 hybrid nanomaterials all had high oxidase or peroxidase catalytic activity as nanoenzymes. However, most of these bimetallic nanoenzymes are produced by hydrothermal synthesis and their water dispersibility was varied, which means it requires innovations to renovate current technique.

PtCu nanoparticles have been widely used in electrochemical catalysis and show excellent performance.6'7 However, the oxidase catalytic activity of PtCu nanoparticles has not been well investigated. In this patent, it introduces a one-pot synthesis method to prepare PtCu nanoparticles in water, and the prepared PtCu nanoparticles show high oxidase catalytic activity.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a simple synthesis method to prepare PtCu nanoparticles with good water dispersibility, and to investigate the oxidase catalytic activity of the prepared PtCu nanoparticles.

In order to solve the above problem, the present invention discloses a one-pot synthesis method for the preparation of PtCu nanoparticles in aqueous solution. The preparation of PtCu nanoparticles should match the following steps: A) 5.0 mL ultrapure water was added into the reaction flask. B) Then H2PtCl6 (20.0 mmol/L) and CuCl2 (20.0 mmol/L) were added to the above solution. (With Pt/Cu atomic ratio of 3:1, noticed that the concentration of total Cu and Pt ions should be 0.2 mmol/L. The prepared nanoparticles were denoted as PtsCui.) C) The mixture was stirred in the ice-water bath for 10 minutes. D) The prepared NaBH4 solution with concentration of 1 mg/mL was added to the above reaction flask under stirring with fixed volume and at the rate of 15 s/drop. E) Once the addition of NaBEE solution was completed, the reaction was under the ice bath stirring for another one hour. F) TEM image of the obtained PtCu nanoparticles is shown in Figure 1.

The investigation of oxidase-like catalytic activity of as prepared PtCu nanoparticles should match the following steps: 50 pL Pt3Cui nanoenzyme was added to 0.4 mL of pH 3.0 solution. The mixture was kept under the constant temperature at 30 °C for 10 minutes. Once done, 20 pL TMB was added to each of the tubes and the reaction was still kept under the constant temperature. During this time, the color change of the solution was observed. After 10 minutes, the absorbance of the mixture was recorded at 650 nm. Repeat three samples for error reduction.

DESCRIPTION OF DRAWINGS

Figure 1: TEM image of PtCu nanoparticles.

Fig.2 Effect of different proportions (A), pFI(B), temperature (C) and substrate concentration (D) on the activity of PtCu nanoenzyme.

DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiment of the present invention will be explained in details so that the present invention can be more readily understood.

The present invention provides includes following: A: Preparation of PtCu nanoparticles with different proportions. A) 5.0 mL ultrapure water was added into the reaction flask. B) Then H2PtCl6 (20.0 mmol/L) and CuCl2 (20.0 mmol/L) were added to the above solution. (With Pt/Cu atomic ratio of 1:5, 1:3, 1:1 and 3:1, 5:1, in addition to only Pt and only Cu solution, noticed that the concentration of total Cu and Pt ions should be 0.2 mmol/L)

C) The mixture was stirred in the ice-water bath for 10 minutes. D) The prepared NaBH4 solution with concentration of 1 mg/mL was added to the above reaction flask under stirring with fixed volume and at the rate of 15 s/drop. E) Once the addition of NaBH4 solution was completed, the reaction was under the ice bath stirring for another one hour. F) Once finished, the oxidase-like activity of PtCu nanoparticles obtained from A-G samples were studied.

According to Figure 2A, the prepared PtCu nanoparticles with a Pt/Cu feeding molar ratio of 3:1 show the highest oxidase-like activity. B: Investigation of the oxidase-like activity of PtCu nanoenzyme mimic dependent on pH value, temperature and concentration of TMB substrate. A) pH value. Choose Pt3Cui sample for analysis. 50 pL Pt4Cui nanoenzyme was added to 0.4 mL of solution with different pH value at 2.0, 2.5,3.0,3.5 , 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 8.0, 9.0, 10.0. The mixture was kept under the constant temperature at 30°C for 10 minutes. Once done, the 20 pL TMB was added to each of the tubes and the reaction was still kept under the constant temperature. During this time, the color change of the solution was observed. After 10 minutes, the absorbance of the mixture was recorded at 650 nm. Repeat three samples for error reduction.

According to Figure 2B, the optimal pH value for this nanoenzyme was 3.0. B) Temperature: Choose Pt3Cui sample for analysis. 50 pL Pt3Cui nanoenzyme was added to 0.4 mL of pH 3.0 solution. The mixture was kept under the constant temperature for 10 minutes. The reactions were carried out at 0, 10, 20, 25, 30, 35, 40, 50, 60°C. The solution was kept under the constant temperature for 10 minutes. After that, 20 pL TMB was added to each of the tubes and the reaction was still kept under the constant temperature. During this time, the color change of the solution was observed. After 10 minutes, the absorbance of the mixture was recorded at 650 nm. Repeat three samples for error reduction.

According to Figure 2C, PtCu nanoenzyme had a broad temperature range, and the optimal temperature for reaction was at range of 30 - 60 °C. C) Concentration of substrate: Choose Pt3Cui sample for analysis. 50 pL Pt3Cui nanoenzyme was added to 0.4 mL of pH 3.0 solution. The mixture was kept under the constant temperature at 30 °C. After 10 minutes, 1,2.5, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 pL TMB was added to each tube, respectively (The rest of the volume was occupied with pH 3.0 solution if the added volume was not equal to 50 pL). The reaction was still kept under the constant temperature. During this time, the color change of the solution was observed. After 10 minutes, the absorbance of the mixture was recorded at 650 nm. Repeat three samples for error reduction.

According to Figure 2D, the optimal concentration of TMB substrate for PtCu nanoenzyme was 0.4 mM.

Claims

1. A one-pot synthesis method for the preparation of PtCu nanoparticles with oxidase-like catalytic activity, including following steps: 1) 5.0mL ultrapure water was added into the reaction flask; 2) Then H2PtCl6 (20.0 mmol/L) and CuCl2 (20.0 mmol/L) were added to the above solution, with Pt/Cu atomic ratio of 3:1, noticed that the concentration of total Cu and Pt ions should be 0.2 mmol/L; 3 ) The mixture was stirred in the ice-water bath for 10 minutes; 4 ) The prepared NaBH4 solution with concentration of 1 mg/mL was added to the above reaction flask under stirring with fixed volume and at the rate of 15 s/drop; 5) Once the addition of NaBH4 solution was completed, the reaction was under the ice bath stirring for another one hour.

2. Investigation of oxidase-like catalytic activity of as prepared PtCu nanoparticles, including following steps: 50 pL Pt3Cui nanoenzyme was added to 0.4 mL of pH 3.0 solution. The mixture was kept under the constant temperature at 30 °C for 10 minutes. Once done, 20 pL TMB was added to each of the tubes and the reaction was still kept under the constant temperature. During this time, the color change of the solution was observed. After 10 minutes, the absorbance of the mixture was recorded at 650 nm.