Disclosure of Invention
Aiming at the defects of the prior method for detecting urea by chromatography, ultraviolet spectrophotometry and the like, the invention aims to provide a rapid urea concentration detection method which has low cost, is suitable for on-site monitoring, is rapid and convenient to use and application thereof
The invention provides a method for rapidly detecting urea concentration, which comprises the following steps:
(1) preparing urease-nano gold composite materials, urea solutions with different concentrations, 790-820nm infrared laser and a barometer;
(2) adding a urea solution with one concentration into the urease-nanogold composite material prepared in the step (1) to form a mixed solution;
(3) irradiating the mixed solution in the step (2) by using the infrared laser in the step (1), converting light energy into heat energy by using the photo-thermal property of nano particles in the mixed solution, heating the solution, accelerating the decomposition of urea into carbon dioxide and ammonia gas under the catalysis of urease, and measuring the air pressure value by using a barometer;
(4) recording the air pressure value in the step (3);
(5) respectively repeating the steps (2) to (4) by using urea solutions with different concentrations to obtain different air pressure values;
(6) drawing a standard curve comparison graph according to the urea solutions with different concentrations respectively corresponding to the different air pressure values obtained in the step (5);
(7) and (3) adding a sample solution to be detected with unknown concentration into the urease-nanogold composite material prepared in the step (1), repeating the step (3) and the step (4) to obtain an air pressure value, and contrasting the air pressure value with the standard curve comparison chart in the step (6) to obtain the urea concentration of the solution to be detected.
The preparation method of the urease-nanogold composite material comprises the following steps:
(1.1) respectively taking 640 mu L of hydroquinone solution with the solution concentration of 100mM, 40 mu L of silver nitrate solution with the solution concentration of 60mM and 40 mu L of chloroauric acid solution with the solution concentration of 25mM, sequentially adding the hydroquinone solution with the solution concentration of 18ml and polyvinylpyrrolidone solution with the solution concentration of 90mM, shaking to change the color of the solution from colorless to blue to light red brick color, adding 200 mu L of concentrated ammonia water, and removing a silver chloride template to obtain the spherical hollow porous nanogold.
(1.2) mixing the spherical hollow porous nano-gold in the step (1.1) with a urease solution, wherein the concentration of the spherical hollow porous nano-gold is 0.05-0.10mg/mL, the concentration of the urease solution is 0.10-0.20mg/mL, the spherical hollow porous nano-gold and the urease solution are assembled according to the volume ratio of (1-2) to (3-4), urease is adsorbed on the spherical hollow porous nano-gold, and then the urease-nano-gold composite material is obtained through centrifugal separation, wherein the particle size of the spherical hollow porous nano-gold in the urease-nano-gold composite material is 100-130 nm.
In the preferable step (1.2), the concentration of the urease solution is 0.15mg/mL, the particle size of the spherical hollow porous nano-gold in the urease-nano-gold composite material is 105nm, the concentration is 0.07mg/mL, and the spherical hollow porous nano-gold and the urease solution are assembled in a volume ratio of 1: 3.
And (3) reacting the spherical hollow porous nano gold and the urease solution in the step (1.2) in a centrifugal tube at room temperature at a shaking table speed of 500r for 8-12h, centrifuging at 13000rpm for 5min, removing free urease, and dissolving with secondary water to obtain the urease-nano gold composite material. The urease solution is dissolved by potassium dihydrogen phosphate buffer solution with pH between 4-6.
The pH value of the urease-nanogold composite material adopted in the step (1) is 4-6, the air pressure is measured by using an air pressure gauge under the condition that the temperature of the urease-nanogold composite material is 60-70 ℃ under the irradiation of infrared laser, and the laser irradiation power is 1.5-2.5W/cm2And reading the barometer after the laser irradiation of 790-820nm for 10-20 min. Preferably, the urease-nanogold composite used in the step (1) has a pH of 5.4, a reaction time of 12 hours, and a gas pressure is measured using a barometer under infrared laser irradiation at a temperature of 60 ℃. The laser irradiation power was 2.0W/cm2Reading the barometer after irradiating for 15min by using laser with wavelength of 808nm
As a further object of the invention is that the method is used for detecting urea concentration in a body fluid of a human.
The invention also aims to provide a urea concentration detection sensor directly obtained by the rapid detection method for the urea concentration, which comprises a urease-nanogold composite material, 790-820nm infrared laser, a barometer and the standard curve comparison chart. The barometer is a portable barometer.
The invention has strong photo-thermal efficiency of the urease-nano gold composite material, can rapidly raise the temperature in a short time, and accelerate the urease to catalyze the urea to decompose into carbon dioxide and ammonia gas, the inventor further discovers that when the urease-nano gold composite material is measured by an air pressure gauge at the pH value of 4-6 and the temperature of 60-70 ℃, the urea concentration and the air pressure value form a very stable direct proportion relation, and by utilizing the corresponding relation, the method can accurately detect the urea concentration, and experiments prove that the method can detect the urea concentration with the sensitivity of 1.00-100mM, and the normal contents of the urea in the urine and the blood of a normal human body are respectively 55-388mM (9.3-23.3g/L) and 2.5-7.5mM (0.15-0.4g/L), and the urea concentration in sweat is 1.8-46 mM, therefore, the detection range of the method meets the detection of urea in body fluid, and can be used for detecting the concentration of urea in body fluid of a human. The method does not need to use precise instruments and equipment, the instant detection effect of the detection sensor directly obtained by the method is very obvious on site, the detection is rapid, the operation is convenient, the sensitivity is high, the detection range is wide, and the detection cost is low, which cannot be compared with the existing equipment.
Detailed Description
In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.
Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
The following is a list of some data from the experiments of the present invention:
TABLE 1 Experimental data List
The concentration of the spherical hollow porous nano gold is within the range of 0.05-0.10mg/mL, the particle size is 100-130nm, the concentration of the urease solution is 0.10-0.20mg/mL, and the volume ratio of the spherical hollow porous nano gold to the urease solution is (1-2) to (3-4); the PBS solution is potassium dihydrogen phosphate, the pH value is between 4 and 6, the spherical hollow porous nano-gold and the urease solution react for 8 to 12 hours under the specified conditions, the pH value of the adopted urease-nano-gold composite material is 4 to 6, and the air pressure is measured by using a barometer under the condition that the temperature of the urease-nano-gold composite material is 60 to 70 ℃ under the irradiation of infrared laser.The laser irradiation power is 1.5-2.5W/cm2And reading the barometer after the laser irradiation of 790-820nm for 10-20 min.
Example 1
An embodiment of the method for rapidly detecting the urea concentration is shown in fig. 1, and a schematic diagram of the principle of the method is shown in the figure. The detection method specifically comprises the following steps:
the first step is as follows: preparing urease-nano gold composite material, urea solution with different concentrations, infrared laser with wavelength of 808nm and a portable barometer.
(1) And (3) synthesizing the urease-nanogold composite material as shown in figure 1.
(1.1) preparation of spherical hollow porous Nanogold
To a round bottom flask containing 18mL of 90mM PVP solution was added 640. mu.L of 100mM hydroquinone, 40. mu.L of 60mM AgNO3The solution is protected from light, 40 mu L of 25mM chloroauric acid is added dropwise while shaking (500r), the solution is placed on a shaking table for continuous reaction for one hour after shaking vigorously for 5min (1000r), and the color of the solution is changed from colorless to blue to light red brick color. Adding 200 mu L of concentrated ammonia water, reacting for 2 hours at 500r under a shaking table, and then deepening the color of the solution; after the reaction, the supernatant was removed by centrifugation and dispersed in 2mL of water to obtain spherical hollow porous nanogold having a particle size of 105nm and a concentration of 0.07 mg/mL.
(1.2) Synthesis of urease-Nanogold composite Material
In this example, the PBS solution is potassium dihydrogen phosphate, pH is 5.4, the concentration of the dissolved urease solution is 0.15mg/mL, 5 μ L of the spherical hollow porous nanogold is taken, and 15 μ L of the urease solution is assembled according to a ratio of 1: 3. And (3) carrying out self-assembly at room temperature at a shaking table speed of 500 r/shaking for 12h, carrying out centrifugal treatment at a rotating speed of 13000rpm for 5min after the assembly is finished, and dissolving with secondary water to obtain the urease-nanogold composite material.
The second step is that: obtaining a standard curve map
(2) Adding a urea solution with one concentration into the urease-nanogold composite material prepared in the step (1) to form a mixed solution;
(3) irradiating the mixed solution in the step (2) by using infrared laser with wavelength of 808nm, heating the mixed solution to release carbon dioxide and ammonia gas, and measuring the air pressure value by using an air pressure meter;
(4) reading the air pressure value in the step (3);
(5) respectively repeating the steps (2) to (4) by using urea solutions with different concentrations to obtain different air pressure values;
(6) and (5) respectively drawing a standard curve comparison graph according to the urea solutions with different concentrations corresponding to the different air pressure values obtained in the step (5), and showing the standard curve comparison graph in a figure 2.
The third step: in actual practice, the urea content in a blood sample of unknown concentration is measured.
(7) Taking a blood sample solution with unknown concentration, adding 80 mu L of solution to be detected into the urease-nanogold composite material prepared in the step (1), and repeating the step (3) and the step (4), wherein the infrared laser with the wavelength of 808nm in the step (3) is used, and the infrared laser with the wavelength of 2.0W/cm is used2Irradiating the solution for 15min, reading the air pressure value, and comparing the air pressure value reading with the standard value comparison chart in the step (6) to quickly obtain the concentration of the urea in the solution to be detected. Knowing that the urea concentration in normal blood is in the range of 2.5-7.5mM, our test range is satisfactory for determining the urea concentration in blood.
Example two
An embodiment of the method for rapidly detecting the urea concentration is shown in fig. 1, and a schematic diagram of the principle of the method is shown in the figure. The detection method specifically comprises the following steps:
the first step is as follows: preparing urease-nano gold composite material, urea solution with different concentrations, infrared laser with the wavelength of 790nm and a portable barometer.
(1) And (3) synthesizing the urease-nanogold composite material as shown in figure 1.
(1.1) preparation of spherical hollow porous Nanogold
To a round bottom flask containing 18mL of 90mM PVP solution was added 640. mu.L of 100mM hydroquinone, 40. mu.L of 60mM AgNO3The solution is protected from light, 40 mu L of 25mM chloroauric acid is added dropwise while shaking (500r), the solution is placed on a shaking table for continuous reaction for one hour after shaking vigorously for 5min (1000r), and the color of the solution is changed from colorless to blue to light red brick color. Adding 200 mu L of concentrated ammonia water, reacting for 2 hours at 500r under a shaking table, and obtaining a solutionDeepening the color; after the reaction, the supernatant was removed by centrifugation and dispersed in 2mL of water to obtain spherical hollow porous nanogold having a particle size of 100nm and a concentration of 0.05 mg/mL.
(1.2) Synthesis of urease-Nanogold composite Material
The spherical hollow porous nanogold obtained in step (1.1) and a urease solution (0.10mg/mL) dissolved in PBS solution (potassium dihydrogen phosphate, pH 4) were each assembled in the following proportions. Shaking for 8h (500r) at room temperature for self-assembly, centrifuging at 13000rpm for 5min after the assembly is finished, and dissolving with secondary water to obtain the urease-nanogold composite material.
And (3) taking 4 mu L of the spherical hollow porous nano gold, and assembling 16 mu L of the urease solution according to the volume ratio of 1: 4.
The second step is that: obtaining a standard curve map
(2) Adding a urea solution with one concentration into the urease-nanogold composite material prepared in the step (1) to form a mixed solution;
(3) irradiating the mixed solution in the step (2) by using 790nm infrared laser, heating the mixed solution to release carbon dioxide and ammonia gas, and measuring the air pressure value by using an air pressure meter;
(4) reading the air pressure value in the step (3);
(5) respectively repeating the steps (2) to (4) by using urea solutions with different concentrations to obtain different air pressure values;
(6) and (5) respectively drawing a standard curve comparison graph according to the urea solutions with different concentrations corresponding to the different air pressure values obtained in the step (5), and showing the standard curve comparison graph in a figure 2.
The third step: in actual practice, the urea content in a blood sample of unknown concentration is measured.
(7) Taking a blood sample solution with unknown concentration, adding 80 mu L of solution to be detected into the urease-nanogold composite material prepared in the step (1), and repeating the step (3) and the step (4), wherein 790nm infrared laser in the step (3) is used, and 1.5W/cm is used2Irradiating the solution for 10min, reading the air pressure value, and comparing the air pressure value reading with the standard value comparison chart in the step (6) to quickly obtain the concentration of the urea in the solution to be detected.Knowing that the urea concentration in normal blood is in the range of 2.5-7.5mM, our test range is satisfactory for determining the urea concentration in blood.
Example three
An embodiment of the method for rapidly detecting the urea concentration is shown in fig. 1, and a schematic diagram of the principle of the method is shown in the figure. The detection method specifically comprises the following steps:
the first step is as follows: preparing urease-nano gold composite material, urea solution with different concentrations, 820nm infrared laser and portable barometer.
(1) And (3) synthesizing the urease-nanogold composite material as shown in figure 1.
(1.1) preparation of spherical hollow porous Nanogold
To a round bottom flask containing 18mL of 90mM PVP solution was added 640. mu.L of 100mM hydroquinone, 40. mu.L of 60mM AgNO3The solution is protected from light, 40 mu L of 25mM chloroauric acid is added dropwise while shaking (500r), the solution is placed on a shaking table for continuous reaction for one hour after shaking vigorously for 5min (1000r), and the color of the solution is changed from colorless to blue to light red brick color. Adding 200 mu L of concentrated ammonia water, reacting for 2 hours at 500r under a shaking table, and then deepening the color of the solution; after the reaction, the supernatant was removed by centrifugation and dispersed in 2mL of water to obtain spherical hollow porous nanogold having a particle size of 130nm and a concentration of 0.10 mg/mL.
(1.2) Synthesis of urease-Nanogold composite Material
To 13.3. mu.L of urease dissolved in PBS (potassium dihydrogen phosphate, pH 4) at a ratio of 1:2 was added 6.7. mu.L of the spherical hollow porous nanogold obtained in step (1.1) at 0.20 mg/mL. Shaking for 12h (500r) at room temperature for self-assembly, centrifuging at 13000rpm for 5min after the assembly is finished, and dissolving with secondary water to obtain the urease-nanogold composite material.
The second step is that: and detecting the urea content in the blood sample with unknown concentration.
Taking a blood sample solution with unknown concentration, adding 80 mu L of solution to be detected into the urease-nanogold composite material prepared in the step (1), and repeating the step (3) and the step (4), wherein 820nm infrared laser in the step (3) is used, and 2.5W/cm is used2Irradiating the solution for 20min at the power of (1), and reading gasAnd (4) reading the pressure value, and comparing the pressure value reading with a standard value comparison map to quickly obtain the concentration of the urea in the solution to be detected.
Example four
An embodiment of the method for rapidly detecting the urea concentration is shown in fig. 1, and a schematic diagram of the principle of the method is shown in the figure. The detection method specifically comprises the following steps:
the first step is as follows: preparing urease-nano gold composite material, urea solution with different concentrations, infrared laser with the wavelength of 810nm and a portable barometer.
(1) And (3) synthesizing the urease-nanogold composite material as shown in figure 1.
(1.1) preparation of spherical hollow porous Nanogold
To a round bottom flask containing 18mL of 90mM PVP solution was added 640. mu.L of 100mM hydroquinone, 40. mu.L of 60mM AgNO3The solution is protected from light, 40 mu L of 25mM chloroauric acid is added dropwise while shaking (500r), the solution is placed on a shaking table for continuous reaction for one hour after shaking vigorously for 5min (1000r), and the color of the solution is changed from colorless to blue to light red brick color. Adding 200 mu L of concentrated ammonia water, reacting for 2 hours at 500r under a shaking table, and then deepening the color of the solution; and after the reaction is finished, centrifuging to remove the supernatant, and dispersing into 2mL of water to obtain the spherical hollow porous nanogold with the particle size of 120nm and the concentration of 0.08 mg/mL.
(1.2) Synthesis of urease-Nanogold composite Material
To 12 μ L of urease dissolved in PBS solution (potassium dihydrogen phosphate, pH 4.5) and 0.17mg/mL, 8 μ L of the spherical hollow porous nanogold obtained in step (1.1) was added, and the assembly ratio was 2: 3. Shaking for 10h (500r) at room temperature for self-assembly, centrifuging at 13000rpm for 5min after the assembly is finished, and dissolving with secondary water to obtain the urease-nanogold composite material.
The third step: and detecting the urea content in the urine sample with unknown concentration.
Taking a urine sample solution with unknown concentration, adding 80 mu L of solution to be detected into the urease-nanogold composite material prepared in the step (1), and repeating the step (3) and the step (4), wherein the solution with the concentration of 810nm and the concentration of 1.6W/cm in the step (3) is used2Irradiating the solution with infrared laser at power for 13min, and reading air pressureAnd (4) reading the value, and comparing the pressure value reading with a standard value comparison map to quickly obtain the concentration of the urea in the solution to be detected. The urea concentration of normal urine is known to be in the range of 55-388mM (9.3-23.3g/L), and the detection range meets the determination of the urea concentration in urine.
Example five
An embodiment of the method for rapidly detecting the urea concentration is shown in fig. 1, and a schematic diagram of the principle of the method is shown in the figure. The detection method specifically comprises the following steps:
the first step is as follows: preparing urease-nano gold composite material, urea solution with different concentrations, infrared laser of 800nm and portable barometer.
(1) And (3) synthesizing the urease-nanogold composite material as shown in figure 1.
(1.1) preparation of spherical hollow porous Nanogold
To a round bottom flask containing 18mL of 90mM PVP solution was added 640. mu.L of 100mM hydroquinone, 40. mu.L of 60mM AgNO3The solution is protected from light, 40 mu L of 25mM chloroauric acid is added dropwise while shaking (500r), the solution is placed on a shaking table for continuous reaction for one hour after shaking vigorously for 5min (1000r), and the color of the solution is changed from colorless to blue to light red brick color. Adding 200 mu L of concentrated ammonia water, reacting for 2 hours at 500r under a shaking table, and then deepening the color of the solution; and after the reaction is finished, centrifuging to remove the supernatant, and dispersing into 2mL of water to obtain the spherical hollow porous nanogold with the particle size of 115nm and the concentration of 0.06 mg/mL.
(1.2) Synthesis of urease-Nanogold composite Material
mu.L of the spherical hollow porous nanogold obtained in step (1.1) was added to 15. mu.L of urease dissolved in PBS (potassium dihydrogen phosphate, pH 5.5) at an assembly ratio of 1:3, at 0.20 mg/mL. Shaking for 11h (500r) at room temperature for self-assembly, centrifuging at 13000rpm for 5min after the assembly is finished, and dissolving with secondary water to obtain the urease-nanogold composite material.
The third step: and detecting the urea content in the urine sample with unknown concentration.
Taking a urine sample solution with unknown concentration, adding 80 mu L of solution to be detected into the urease-nanogold composite material prepared in the step (1), and repeating the step (a)3) And a step (4) of using the infrared laser of 800nm in the step (3) with 1.7W/cm2The solution is irradiated for 18min, the reading of the air pressure value is read, and the comparison is carried out by using the reading of the air pressure value and a standard value comparison map, so that the concentration of the urea in the solution to be detected can be quickly obtained. Knowing that the urea concentration of normal urine is in the range of 55-388mM (9.3-23.3g/L), our assay range is satisfactory for determining the urea concentration in urine.