TW201337256A - Method of measuring glycosylated protein proportion by AC impedance method - Google Patents

Abstract

A method of measuring a glycosylated protein proportion by all AC impedance method includes passing all AC voltage or AC to two inspecting electrodes; covering a solution containing glycosylated protein completely onto the inspecting electrodes; measuring an impedance value between the electrodes and calculating the difference between the impedance value and an impedance value of a solution without glycosylated protein by all AC impedance inspection device; comparing the impedance difference with AC impedance difference/glycosylated protein concentration to obtain the proportion of the glycosylated protein in the solution containing glycosylated protein. The solution without glycosylated protein includes a salt solution and a non-glycosylated protein; the proportion of glycosylated protein in the solution containing glycosylated protein refers to the proportion of glycosylated protein in the total quantity of protein in the salt solution; and the proportion of glycosylated hemoglobin of the total quantity of hemoglobin in the salt solution.

Description

Method for measuring the proportion of glycated protein by using an alternating current impedance method

The present invention relates to a method for measuring the ratio of glycated proteins using an alternating current impedance method.

Diabetes control often uses blood sugar levels as a control indicator, suggesting that the closer the blood sugar is to the normal value, the better the blood sugar control; and the relevant blood glucose measurement techniques such as the Republic of China Patent No. M384315 "non-invasive optical blood glucose tester" , No. I295566 "Glucose detection instrument with blood collection gun structure", or US Patent Publication No. 2009/0292186 "Method and System for Non-Invasive Optical Blood Glucose Detection Utilizing Spectral Data Analysis", etc., are direct quantities Measure the blood sugar level in the blood.

However, in fact, blood sugar will change greatly with time and diet. The blood glucose test value only represents the blood sugar value at the time of the investigation, so it is absolutely impossible to use this blood glucose value as absolute diabetes control. index.

In normal red blood cells, hemoglobin (Hb) accounts for more than 95%. When the body loses insulin control, glucose will be released into the blood in a large amount, and the glucose in the blood will slowly combine with Hb to form glycosylated hemoglobin (HbA). ₁ C), because the process of HbA ₁ C formation is slow and requires time to accumulate, the level of HbA ₁ C is related to the daily average blood glucose concentration, and does not change immediately due to changes in blood glucose concentration before and after meals. There is no significant difference; therefore, according to the degree of binding of glucose and Hb, the WHO indicates that when glycated hemoglobin accounts for more than 6.5% of the total hemoglobin amount, it can be considered as suffering from diabetes.

Therefore, in recent years, the detection of HbA ₁ C content has been widely used to monitor the average blood glucose level of diabetic patients, and since the life span of red blood cells is about 3 months, it is considered that HbA ₁ C content reflects the blood sugar control status about 3 months before blood collection. It can be used to monitor the situation of blood sugar control and can be used as a basis for dose adjustment. According to estimates by the International Diabetes Federation, the current global diabetes population is approximately 200 million, and the number of diabetes worldwide is estimated to be 2025. More than 300 million people, so the detection of HbA ₁ C has great business opportunities in the future, is a technology worthy of research and development, and the fast and convenient HbA ₁ C detection technology can also help diabetic patients accurately control blood sugar levels in the body and reduce the occurrence of complications. .

For the detection of HbA ₁ C, there is a method and apparatus for rapid measurement of HbA ₁ c, which is a method using optical detection; or US Patent Publication No. US2010/0178659 "METHOD" OF MEASURING HbA ₁ c" is a method for detecting enzymes. In addition, there are electrochemical measurement methods. The electrochemical measurement methods are DC and AC. For biosensors, Mainly based on the direct current measurement, such as the US Patent No. US7998017 "Systems and methods for replacing signal artifacts in a glucose sensor data stream", while the direct current measurement method mainly uses cyclic voltammetry, but in the face After the surface modification having the surface conductivity of the detecting electrode is lowered, the electron transfer activity of the detecting electrode is lowered, and at this time, the measurement between the detecting electrode and the object to be tested cannot be appropriately used by the cyclic voltammetry.

The AC impedance measurement method can solve the aforementioned deficiency, and therefore there is an invention of measuring a glycated protein using an AC impedance, for example, US Patent No. US 2011/0123399 "DEVICE FOR MEASURING PROTEINS USING BIOSENSOR".

Further, there is also the use of alternating current stimulation as a technical means for treating diabetes, for example, US Patent No. US 2009/0254133 "Method for treatment of diabetes by electrostimulatioin", which discloses that the available frequency is between 0.00065 Hz and 0.00085 Hz, and the amperage AC stimulation at 20 amps to 1 atto (10 ^-18 amps) achieves therapeutically controlled glycemic stability in insulin-dependent diabetic patients.

In view of the advantages of AC impedance measurement, the present invention can distinguish between biomolecules according to changes in frequency, voltage, current, impedance or phase of biomolecules based on their own electrical characteristics. Different changes, so the impedance electrochemical biosensing wafer is used in combination with the AC impedance method to distinguish the difference between glycated protein and unglycosylated protein. For example, glycated hemoglobin (HbA ₁ C) and heme (Hb) can be used. Judging the proportion of glycated hemoglobin in the body to total heme.

The glycated protein and the non-glycosylated protein are detected in a salt solution which is generally compatible with human tissue cells, which can prevent the denaturing of the glycated protein and the unglycosylated protein after being taken out of the body, and the charged ions which are separated from the salt solution will be glycated. The salt gain is diluted by the increase in signal gain and interference on the detection of protein and unglycosylated proteins.

Therefore, the present invention is a method for measuring the proportion of glycated protein by an alternating current impedance method, the method comprising: introducing an alternating voltage or an alternating current to a pair of detecting electrodes, and completely covering the detecting electrode with the glycated protein solution, through a The AC impedance detecting device obtains the impedance value between the electrodes; calculates the impedance difference between the impedance value and the impedance value of the solution containing no glycated protein; and compares the impedance difference with an AC impedance difference/glycoprotein concentration relationship to obtain the glycation The ratio of protein in the glycated protein solution.

The AC impedance difference/glycoprotein concentration relationship is established by: obtaining an A-glycated protein solution through the AC impedance detecting device, and dissolving different concentrations of glycated protein in the B-the aforementioned glycated protein-free solution; The impedance value of the two is taken as the impedance difference between A and B, and the relationship between the impedance difference and the impedance difference is obtained after the saccharified protein solution is dissolved in different concentrations of the glycated protein, so that the curve needs to be correspondingly exchanged. Impedance difference/glycosylated protein concentration relationship; the un-glycosylated protein solution mainly comprises a salt solution and an un-saccharified protein, and the total amount of the glycated protein and the un-saccharified protein is defined as total protein, and the glycated protein is in the glycated protein solution. The ratio in the medium refers to the ratio of the glycated protein to the total protein under the salt solution. Further, the glycated protein is glycated hemoglobin, and the un-saccharified protein is un-saccharified hemoglobin, and the total amount of the glycated hemoglobin and the un-saccharified heme is defined as total heme, and the ratio of the glycated protein to total protein is Refers to the ratio of the glycated hemoglobin to the total heme in the salt solution. The ratio of glycated hemoglobin is between 0% and 10% of total hemoglobin. The relationship between the AC impedance difference and the glycosylated protein concentration is a relationship between the AC impedance difference and the glycated hemoglobin concentration.

The effect of the invention is:

Alternating current impedance of the pre-established difference / concentration relationship of glycated proteins, glycated hemoglobin when used (HbA ₁ C) and the non-glycated hemoglobin (Hb) detection, can be easily achieved glycated hemoglobin (HbA ₁ C) of the total The ratio of hemoglobin is a rapid, simple and accurate method for determining whether or not you have diabetes, or to monitor the blood sugar control of diabetic patients.

In summary of the above technical features, the main effects of the method of the present invention for measuring the ratio of glycated proteins by the AC impedance method can be clearly shown in the following examples.

Heme is a protein, so the glycated protein of this example is exemplified by glycated hemoglobin (HbA ₁ C), and the unsaccharified protein is exemplified by un-glycated hemoglobin (Hb), glycated hemoglobin (HbA ₁ C) and The total amount of unstained hemoglobin (Hb) is total heme.

First to note that, upon detection of Hb and HbA ₁ C of the AC impedance, and Hb HbA ₁ C needs test sample was dissolved in a solution of salts, avoiding denaturation Hb and HbA ₁ C is taken after in vitro, but also consider salt The ion concentration is too high to interfere with the influence of the AC impedance measurement, so the present invention uses a deionized water to dilute a salt solution having a concentration equivalent to physiological saline to a volume percentage of between 0.01% and 90%, and Preferably, the salt solution is diluted to a volume percentage of between 0.01% and 1%, and the salt solution is compatible with human tissue cells, for example, physiological saline or phosphate buffer solution (PBS), wherein phosphoric acid is used. The salt buffer solution can be prepared by dissolving a PBS in 100 ml of deionized water. The above PBS contains 10 millimoles of phosphate, 137 millimoles of sodium chloride and 2.7 millimoles of potassium chloride. The PBS solution was diluted with deionized water.

Referring to the first figure, the detection electrode is used to measure the AC impedance of Hb dissolved in different dilution ratios of salt solution under different frequencies, and the impedance spectrum of relative impedance difference (dZ) is plotted to illustrate the present invention. For the reason of choosing the above salt solution, the concept of relative impedance difference (dZ) is expressed by formula (i):

(i)

Where dZ is the relative impedance difference, Z _Hb is the impedance value of the salt solution containing Hb, and Z _bg is the impedance value of the pure salt solution; wherein the parameter in the figure is set to input AC voltage 20mV, frequency 42Hz to 1MHz, Hb The concentration was 0.2 mg/ml.

It can be seen from the impedance spectrum of the first graph that the higher the salt concentration of the salt solution, the smaller the relative impedance difference dZ, so the test sample considering the Hb should be dissolved in the salt solution, and the salt ion concentration should be considered too. High interference to the influence of the AC impedance measurement makes the relative impedance difference dZ become inconspicuous, so the aforementioned salt solution is diluted to a volume percentage between 0.01% and 90% by dilution method, and preferably between Between 0.01% and 1%.

Referring to the second and third figures, the impedance difference curves of different concentrations of Hb and HbA ₁ c are plotted at different frequencies, and the impedance spectra of the same concentration of 0.04 mg/ml are compared. As shown in the four figures, it can be seen that the two have different impedance differences at the same concentration. At a frequency of 5.3 kHz, the Hb impedance difference is about 23.8 kΩ, and the HbA ₁ c impedance difference is about 256.5 KΩ. Difference, therefore it is expected that at the same concentration of 0.04 mg / ml, mixing different ratios of Hb and HbA ₁ c in the above salt solution, the impedance difference will be between the two.

Referring to the fifth and sixth figures, according to the foregoing experimental results, the method of the present invention takes glycated hemoglobin and heme as an example:

First, an alternating voltage or an alternating current is applied to a pair of detecting electrodes for detecting: A-free glycated hemoglobin solution, and B-the above-mentioned glycated hemoglobin solution are dissolved in different concentrations of glycated hemoglobin, and transmitted through an alternating current impedance The detecting device obtains the impedance values of the two, wherein the solution containing no glycated hemoglobin mainly comprises a salt solution and unstained hemoglobin, and then the impedance difference between A and B is taken to obtain a solution containing no glycated hemoglobin. After dissolving different concentrations of glycated hemoglobin, the relationship between the impedance difference and the curve is obtained by the corresponding AC impedance difference/glycated heme concentration relationship; further, and can be used for AC voltage or AC current. Full spectrum scanning, and the spectral range is between 1 Hz and 1 MHz. In this embodiment, the impedance value under the fixed frequency band of 5.3 KHz in the aforementioned spectral interval is taken to analyze the ratio of glycated hemoglobin ratio to impedance difference.

It should be further explained that the above-mentioned glycosylated hemoglobin solution is dissolved in different concentrations of glycated hemoglobin, which means that different ratios of glycated hemoglobin and unsaccharified hemoglobin are dissolved in the salt solution, in view of WHO recommendation HbA ₁ C More than 6.5% can be regarded as suffering from diabetes. Therefore, the ratio of glycated hemoglobin in the sampling interval in this example is between 0% and 10% of total hemoglobin, and the concentration of total hemoglobin dissolved in the salt solution is controlled to be greater than 0.001 mg. /ml is less than 1 mg / ml, as shown in the fifth figure, when the concentration of total heme in the salt solution is between 0.001 mg / ml to 1 mg / ml, the slope is large, indicating its sensitivity Preferably, when the specific concentration of the curve shown in the fifth figure is taken, the curve shown in the sixth figure can be obtained.

When actually used for detecting the ratio of glycated hemoglobin, an alternating voltage or an alternating current is applied to a pair of detecting electrodes, and the glycated hemoglobin solution is completely covered on the detecting electrode, and the impedance value between the electrodes is obtained through the alternating current impedance detecting device. And calculating an impedance difference between the impedance value and the impedance value of the pre-measured non-glycated heme solution, and obtaining the glycosylated hemoglobin by the impedance difference ratio to the AC impedance difference/glycated heme concentration relationship In the proportion of the glycated hemoglobin solution, since the aforementioned glycated hemoglobin solution contains a salt solution and unstained hemoglobin, the ratio of glycated hemoglobin in the glycated hemoglobin solution refers to the salt solution. Next, the glycated hemoglobin accounts for the proportion of the total hemoglobin, so we can understand the status of hemoglobin saccharification in the user, as a judgment of whether or not suffering from diabetes, or to observe the blood sugar control state of diabetes.

In view of the foregoing description of the embodiments, the operation and the use of the present invention and the effects of the present invention are fully understood, but the above described embodiments are merely preferred embodiments of the present invention, and the invention may not be limited thereto. </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt;

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The first figure is the impedance spectrum of the un-saccharified hemoglobin dissolved in the salt solution of different dilution ratios and the relative impedance difference dZ.

The second figure is the impedance spectrum of the impedance difference DeltaZ in the different concentrations of Hb in the embodiment of the present invention.

The third figure is the impedance spectrum of the impedance difference DeltaZ of different concentrations of HbA ₁ C in the embodiment of the present invention.

The fourth figure is the impedance spectrum of the impedance difference DeltaZ of Hb and HbA ₁ C at the same concentration in the embodiment of the present invention.

The fifth figure is the impedance spectrum of the fixed impedance band in the embodiment of the present invention, and the density corresponding to the impedance difference DeltaZ of HbA ₁ C at different ratios of total hemoglobin.

The sixth figure is the impedance spectrum of the impedance difference corresponding to the different proportions of total hemoglobin in HbA ₁ C at a fixed concentration.

Claims (14)

A method for measuring a ratio of glycated protein by an alternating current impedance method, comprising the steps of: introducing an alternating voltage or an alternating current to a pair of detecting electrodes, and completely covering a detecting layer of the glycated protein solution through an alternating current impedance detecting device; Obtaining an impedance value between the electrodes; calculating an impedance difference between the impedance value and an impedance value of the non-glycated protein solution; comparing the impedance difference to an AC impedance difference/glycoprotein concentration relationship to obtain a glycosylated protein in the glycated protein The ratio in the solution. A method for measuring a ratio of glycated proteins by an alternating current impedance method as described in claim 1, wherein the AC impedance difference/glycoprotein concentration relationship is established by: obtaining an A-through through the AC impedance detecting device. The saccharification protein solution, and the impedance value of the saccharified protein solution of the B-containing saccharified protein solution are dissolved in different concentrations, and the impedance difference between the two is obtained, so that the saccharified protein solution is dissolved in different concentrations. After saccharification of the protein, the curve of the impedance difference, the curve of the AC impedance difference / glycosylated protein concentration corresponding to the curve is obtained. The method for measuring the proportion of glycated protein by the alternating current impedance method according to the first aspect of the patent application is as follows: introducing an alternating voltage or an alternating current to the detecting electrode to obtain an impedance value of the glycated protein solution and the solution containing no glycated protein solution. Further, it can perform full spectrum scanning of AC voltage or AC current, and the spectrum interval is between 1 Hz and 1 MHz. For example, in the method of measuring the proportion of glycated protein by the alternating current impedance method according to the third aspect of the patent application, an alternating current voltage or an alternating current is applied to the detecting electrode, and the impedance value in the fixed frequency band of the spectrum interval is further taken for saccharification. Analysis of the ratio of protein ratio to impedance difference. A method for measuring a ratio of glycated proteins by an alternating current impedance method as described in claim 1, wherein the non-glycated protein solution comprises a salt solution and an unsaccharified protein. The method for measuring the proportion of glycated protein by the alternating current impedance method as described in claim 5, wherein the salt solution is diluted with deionized water in advance, and the dilution volume percentage ranges from more than 0.01% to less than 90%. The method for measuring the proportion of glycated protein by the alternating current impedance method according to the fifth aspect of the patent application, wherein the total amount of the glycated protein and the unsaccharified protein is defined as total protein, and the ratio of the glycated protein to the glycated protein solution is Refers to the ratio of the glycated protein to the total protein under the salt solution. The method for measuring a ratio of glycated proteins by an alternating current impedance method according to claim 7, wherein the glycated protein is glycated hemoglobin, the unsaccharified protein is unsaccharified heme, and the glycated hemoglobin and the unsaccharified The total amount of hemoglobin is defined as total hemoglobin, and the ratio of the glycated protein to total protein refers to the ratio of the glycated hemoglobin to the total heme in the salt solution. The method for measuring the proportion of glycated protein by the alternating current impedance method as described in claim 8 of the patent application, wherein the concentration of total hemoglobin in the salt solution is controlled to be greater than 0.001 mg/ml and less than 1 mg/ml. The method for measuring the proportion of glycated protein by the alternating current impedance method as described in claim 9 of the patent application has a ratio of glycated hemoglobin between 0% and 10% of total heme. The method for measuring a ratio of glycated protein by an alternating current impedance method according to claim 1, wherein the glycated protein is glycated hemoglobin, the glycated protein solution is a glycated hemoglobin solution, and the non-glycated protein solution The method comprises a salt solution and an un-saccharified hemoglobin, wherein the total amount of the glycated hemoglobin and the un-saccharified hemoglobin is defined as total hemoglobin, and the ratio of the glycated protein in the glycated protein solution refers to the salt. Under the solution, the glycated hemoglobin accounts for the proportion of the total heme. A method for measuring a ratio of glycated proteins by an alternating current impedance method as described in claim 11 wherein the ratio of glycated hemoglobin is between 0% and 10% of total hemoglobin. The method for measuring the proportion of glycated protein by an alternating current impedance method according to claim 11, wherein the relationship between the AC impedance difference/glycoprotein concentration is an AC impedance difference/glycated heme concentration relationship, which is The following method is established: the A-free glycated hemoglobin solution is obtained through the AC impedance detecting device, and the impedance value of the different concentrations of glycated hemoglobin is dissolved in the B-containing glycated hemoglobin solution, and A and B are taken. The difference between the two is obtained, and the relationship between the impedance difference and the impedance difference after the glycosylated hemoglobin solution is dissolved in different concentrations of glycated hemoglobin is obtained, and the curve corresponding to the AC impedance difference/glycated heme concentration is required to be detected. . The method for measuring the proportion of glycated protein by the alternating current impedance method according to claim 11 is the method of introducing an alternating voltage or an alternating current to the detecting electrode to obtain a solution containing glycated hemoglobin and a solution containing no glycated hemoglobin. The impedance value can be further scanned for full spectrum of AC voltage or AC current, and the spectrum interval is between 1 Hz and 1 MHz.