China Wuhan Desheng Biochemical Technology Co., Ltd Company News

Luminol is abbreviated as luminol, which is a commonly used chemiluminescence reagent. It can emit a light blue glow when oxidized by an oxidant. It is usually used to detect blood stains in criminal investigations or used with POD for biochemical detection of chemiluminescence equipment.   Some people find that the luminous efficiency is not high when experimenting with luminol. What is the reason? Usually luminol is oxidized to emit light, and the effect is very obvious. If there is flashing or weak luminescence or no luminescence, there may be several reasons: 1. Luminol reagent problem Luminol is a luminescent reagent and is very sensitive to light, so it is usually stored in an opaque brown bottle sealed at low temperature. If luminol expires or has been partially oxidized, the luminous efficiency will be reduced or no light will be emitted.   2. Low peroxidase activity   When luminol is used in biochemical detection, it is usually oxidized with hydrogen peroxide, which needs to be catalyzed by peroxidase POD. If the enzyme activity is low, it will affect the oxidative luminescence performance of luminol. Enzyme catalytic reaction requires high temperature and pH value. Too much sodium hydroxide increases alkalinity or impurities in the system will affect enzyme activity.   Third, the concentration of the excitation solution and the proportion of ingredients The excitation liquid used for luminol luminescence usually refers to hydrogen peroxide solution and sodium hydroxide solution. When used in different sample detection tests, there are certain differences in the concentration of materials. The proportion of ingredients and the order of reagent addition are all related to the entire chemical The luminescence experiment has an impact, this needs to be adjusted for a specific experiment.   Some luminol chemiluminescence experiments were not completed under the catalysis of peroxidase, but potassium ferricyanide, ferric chloride, ferrous sulfate, potassium dioxalate ferrite, etc. were used as catalysts to catalyze the oxidation of H2O2. Mino. When using this type of catalyst, pay attention to the iron ion concentration not too high, otherwise luminol will easily cause instant flashing.   If the chemiluminescence effect of luminol is not good, it is mainly due to the above reasons. Desheng is a manufacturer of chemiluminescent reagents such as luminol and acridinium esters. According to experience, novices who buy luminol reagents for experiments should do a few more regular tests based on the above circumstances to cause the problem early.

Lithium-ion batteries have the advantages of high capacity, high voltage, small size, and light weight. They are widely used in electronic products such as mobile phones, notebook computers, and video cameras, and have become one of the main energy sources for communication electronic products. With the continuous expansion of the application fields of lithium-ion batteries, people have more and more requirements for their cycle life, and carbomer resin as an additive can improve the recycling performance of the battery.   Factors that affect the cycle life of lithium-ion batteries include many aspects, such as the selection of electrode active materials and inactive ingredients used, and the bonding strength of the coating. In the electrode, the main function of the binder is to bond the electrode active material to the current collector. The requirement for the binder is small ohmic resistance, stable performance in the electrolyte, no expansion, no looseness, and no powder removal. Generally speaking, the properties of the adhesive, such as adhesion, flexibility, alkali resistance, and hydrophilicity, directly affect the performance of the battery.   At present, polyvinylidene fluoride (PVDF) is generally used as a binder for lithium-ion batteries in industrial production. However, the pole pieces made of PVDF have poor flexibility, swell easily in the electrolyte, and are expensive. Therefore, high-performance electrode binders have become an important research direction of key materials for lithium-ion batteries. Kim et al. used styrene-butadiene rubber (SBR) as a binder and sodium carboxymethyl cellulose (CMC) as a thickener, and found that the binder was unevenly dispersed in the electrode sheet, and the CMC adhesion performance was poor. Trace amounts of residual moisture will have a serious impact on battery performance.     Cross-linked acrylic resin (carbomer resin) is a high molecular polymer of acrylic acid bonded allyl sucrose or pentaerythritol allyl ether, which has high adhesion. It has been reported in the literature that carbomer resin used in lithium-ion batteries can improve battery cycle performance. For this reason, some experts have studied and investigated the peeling strength of the pole piece, the stability of the electrolyte, the polarization of the battery, and the electrode after adding pure carbomer resin, pure PVDF and the 1:1 combination of the two in the positive electrode of the lithium ion battery. The influence of surface passivation film and electric double layer on impedance and cycle performance.   The results of the study found that by adding different proportions of carbomer resin to the lithium ion battery, the porosity of the pole piece is higher after the kaohm resin is added to the positive electrode, the peeling strength between the pole piece dressing and the electrode fluid increases, and the adhesion performance is significant After the pole piece is soaked in the electrolyte, the force between the pole piece dressing and the electrode fluid is not destroyed by the electrolyte. As the carbomer resin content in the positive electrode is gradually added, the polarization of the battery is improved. The impedance of the passivation film and the electric double layer on the battery electrode surface of the carbomer resin is significantly reduced, and the cycle performance of the battery is improved.   As a professional carbomer manufacturer, Desheng has professional advantages in independent research and development and synthesis. It can provide customers with free samples of carbomer 980 and carbomer 940. Its cost-effectiveness and high quality have been widely recognized by customers.

Acridine ester derivatives are a class of chemiluminescence reagents with high quantum yield. Because of their low initiator requirements, low background and noise, and high sensitivity during the luminescence process, they are often used in clinical immunoassays. It can be used as nucleic acid molecular probes to measure the activity of biological enzymes or other applications. It can label antibodies and is widely used in immunoassays. Such compounds can quickly produce chemiluminescence in the presence of hydrogen peroxide and have high chemiluminescence efficiency. In addition, because acridine esters have a structure similar to acetophenone esters and have a single ester bond, the detection sensitivity is high, so they can be used for the detection of enzyme activity.     As an efficient chemiluminescent reagent, acridinium ester has a wide range of applications in clinical immunoassay, DNA analysis, biological enzyme activity determination, etc. This article focuses on the application of acridine esters in DNA determination. Acridinium esters can be used for genetic testing or microbial testing in terms of DNA.   Application of acridinium ester in DNA determination:   Acridine esters can be used to label oligonucleotide fragment probes for genetic or microbial assays. Acridine ester compounds are very suitable for labeling DNA strands to make chemiluminescent DNA probes. Modern medical research results show that many diseases such as cancer and genetic diseases are related to DNA mutations, and many infectious diseases are caused by viruses, bacteria or parasites in the environment. The analysis of specific sequence DNA of viruses is beneficial Control of the epidemic. The detection of DNA sequence and base mutations in its chain has far-reaching significance in gene screening, early diagnosis and treatment of genetic diseases, and pathogenic gene determination.   In nucleic acid hybridization analysis, the preparation of labeled probes with strong specificity and high sensitivity is the key to successful nucleic acid hybridization analysis. Acridinium ester derivatives can be directly labeled on nucleic acid probes without the need for catalysts and the luminescence quantum yield is not affected. In addition, under certain conditions, the labeled acridinium ester on the unhybridized single-stranded DNA is hydrolyzed and destroyed, and only the double-stranded protected acridinium ester formed by hybridization can produce chemiluminescence, and the entire hybridization process can be monitored without separation.   Based on this principle, some researchers have established a new gene microarray method for hybridization protection detection of aldehyde dehydrogenase and Alzheimer's disease-related gene ApoE. This method designed two biotin-labeled DNA probes to detect the A/G site polymorphism of aldehyde dehydrogenase, and three biotin-labeled DNA probes were used to detect C/T at two sites of ApoE Polymorphism, label the acridinium ester at the mutation site, and then fix the DNA probe on the microtiter plate coated with streptavidin. Only when the target DNA and the probe DNA are completely matched, can acridine be guaranteed The pyridine ester is not hydrolyzed, and the aldehyde dehydrogenase and ApoE genes can be determined based on the presence or absence of chemiluminescence. Wang Xiaojuan and others used acridine ester as a chemiluminescence indicator embedded in the double helix structure of DNA, and used 0.1mol/LHNO3 and 3%H2O2 as well as 0.3mol/LNaOH plus 2%TritonX-100 as the luminescence starting reagent, and established a simple evaluation A new method for chemiluminescence analysis of DNA break damage.   The results showed that low concentration of formaldehyde caused DNA breakage damage, high concentration of formaldehyde caused DNA strand cross-linking, and acetaldehyde only caused DNA strand breakage damage. At the same time, the damage behavior and possible mechanisms of formaldehyde and acetaldehyde to DNA were studied. Acridine esters are also used as DNA probes for the determination of HBV and HIV type I and II DNA, HIV-I DNA oligonucleotide probes for gag gene determination and immunoassays, DNA oligonucleotide probes for determination of ΔF508, ΔI507 Cystic fibrosis gene mutation, etc.   Desheng has been focusing on the development and production of chemiluminescent substrates for more than ten years. It can provide 6 kinds of acridinium ester products (acridinium ester DMAE-NHS, acridinium ester NSP-DMAE-NHS, acridinium salt NSP-SA , Acridine salt NSP-SA-NHS, acridine hydrazide NSP-SA-ADH, acridine ester ME-DMAE-NHS), as well as luminol and isoluminol. If you need it, you can click on the official website to consult our customer service or call us directly.

Chemiluminescence immunoassay is a combination of chemiluminescence and immunoassay. It has both the high sensitivity of chemiluminescence and the high selectivity of immunoassay. The combination of the two is through the chemiluminescence reaction reagent (such as acridinium ester, alkaline phosphatase, etc.) and antibody or antigen labeling, the labeled antibody or antigen and the test substance undergo a series of immune reactions, physical and chemical steps (separation, Washing, etc.), and finally determine the luminous intensity to indirectly determine the content of the analyte. The choice of chemiluminescent markers determines the characteristics of the reaction system, as well as the characteristics of the instrument and reagents.   Chemiluminescence can be divided into three categories, direct chemiluminescence, enzymatic chemiluminescence, and electrochemiluminescence. Direct chemiluminescence uses light-emitting molecules, such as acridinium esters, luminols, etc. The representatives of manufacturers that use acridinium esters for direct chemiluminescence include Abbott, Siemens, Desheng Chemical, etc. So how do chemiluminescence manufacturers on the market choose? ? We have conducted statistical analysis on several major domestic chemiluminescence manufacturers. Desheng Chemical uses acridinium ester and luminol direct chemiluminescence, Roche uses electrochemiluminescence for diagnosis, Abbott uses acridinium ester direct chemiluminescence, and Beckman uses alkaline phosphatase-AMPPD luminescence system. For historical reasons, Siemens has three platforms under its control. The Centaur platform uses acridine ester direct chemiluminescence, the IMMULITE platform uses alkaline phosphatase chemiluminescence, and DIMENSION uses homogeneous photo-induced chemiluminescence.   Number of different chemiluminescence manufacturers   On the whole, in this statistics, the number of chemiluminescence manufacturers using alkaline phosphatase is the most, with a total of 32 platforms, accounting for more than one-third; followed by acridinium chemiluminescence, with 23 platforms using acridinium esters Direct chemiluminescence. If the open chemiluminescence platform compatible with acridine ester and alkaline phosphatase is included, the number of chemiluminescence platforms using alkaline phosphatase or acridinium ester reaches 63, which is 75% higher. It can be seen that the mainstream of the current market is the alkaline phosphatase and acridinium ester chemiluminescence platform. The second is the horseradish peroxidase (HRP) system, electrochemiluminescence due to patent intellectual property issues, this field has been firmly occupied by Roche.   Desheng Chemical is a professional manufacturer of chemiluminescence reagents. There are five acridinium ester products, including DMAE-NHS, NSP-DMAE-NHS, NSP-SA, NSP-SA-NHS, ME-DMAE-NHS, luminescence reagents The product has high purity, high sensitivity and stable supply from the manufacturer. With excellent product quality, it has accumulated a group of stable repurchase customers. Welcome to consult and order.

As an important chemiluminescent reagent, acridine ester plays an important role in chemiluminescence immunoassay. Compared with other luminescence systems, it has its special advantages: for luminescent markers, the label of acridine esters is relatively Simple, stable luminescence of the marker, long validity period of the kit, and relatively low cost; and the luminescence is flash type, the luminescence is fast and concentrated, and the intensity is high, which is convenient to realize rapid detection, and the detection sensitivity and precision are high. The requirements are relatively simple and easy to realize fully automated operation; in addition, the acridinium ester luminescence system has few interference factors, extremely low background, and high signal-to-noise ratio. Based on these advantages of the acridine ester luminescence system, the research and development of a chemiluminescence substrate solution suitable for the acridinium ester chemiluminescence system is of very positive significance.     Method for preparing acridine ester chemiluminescent substrate solution:   A chemiluminescence substrate solution suitable for acridine ester luminescence system, buffer A and buffer B separately stored before use:   Buffer A: inorganic acid and oxidant, and the pH of buffer A is less than 2; the concentration of acid is 0.03-0.10M, and the mass concentration of oxidant is 0.3-1.2wt%;   Buffer B: inorganic base and enhancer, and the pH of buffer B>13; the concentration of base is 0.2-0.65M, and the mass concentration of enhancer is 0.2-2wt%. The volume ratio of buffer A and buffer B is 2:3-3:2.   (1) Preparation of Buffer A: Put 4.2L purified water, 41.7mL 37% hydrochloric acid and 50.2g carbamide peroxide in a 5L wide-mouth glass container that is protected from light, add purified water to make the volume to 5L, stir and mix, and filter to obtain Buffer A;   The pH of the preparation buffer A is 1.0, where the concentration of hydrochloric acid is 0.10M, and the mass concentration of carbamide peroxide is 1.0 wt%;   (2) Preparation of buffer B: Add 4L purified water and 100.6g octaalkyltrimethylammonium chloride to a 5L wide-mouth glass container in turn, stir until the solid is completely dissolved, add 80.0g sodium hydroxide, and stir until complete After dissolving, add purified water to make the volume to 5L, and filter to obtain buffer B; The pH of the preparation buffer B was 13.3, the concentration of sodium hydroxide: 0.40M; the concentration of octaalkyltrimethylammonium chloride: 2.0wt%.   As a manufacturer, Desheng has been researching and developing in the field of chemiluminescence reagents for 15 years. The acridinium ester series developed by it has the advantages of good stability, high sensitivity, wide detection range and low cost.

The TRIS-HCL buffer is stable. It can be widely used in the preparation of buffers in biochemistry and molecular biology experiments. It has good compatibility with physiological body fluids and will not form precipitates with calcium and magnesium ions. On the contrary, phosphate and calcium and magnesium ions will produce precipitation. Moreover, the ionic strength of TRIS-HCL buffer with the same pH and same concentration is lower than that of phosphate buffer. This is particularly important for enzyme determination. Because of the high ionic strength, some enzymes are easily inactivated. Therefore, sometimes using TRIS-HCL instead of phosphate buffer, the effect is better.   However, the pH of TRIS-HCL buffer is greatly affected by temperature. Once the temperature changes, the pH will change significantly. The problem of causing changes in enzyme activity has not attracted enough attention from the clinical laboratory. For this reason, we measured the temperature coefficient of TRIS-HCL buffer and discussed its practical value. The Tris reagent used in the following experiment was developed and produced by Tecsun Technology. Desheng TRIS buffer packaging Experimental process: Put the TRIS-HCL buffer in a 37℃ water bath for 30 minutes. Distilled water, the calibration solution remains at room temperature. Place the temperature knob at 37°C, and take out the buffer after equilibrating the temperature. Adjust zero with distilled water at room temperature, calibrate with mixed phosphate at room temperature (pH 6.84 at 37°C), and immediately determine the pH of the TRIS-HCL buffer. The buffer is placed at room temperature until the temperature drops to 23°C. Adjust to zero with distilled water at room temperature. Calibration of mixed phosphate at room temperature (pH 6.86 at 23°C), and then immediately determine the corresponding pH. The solution was kept at room temperature. Wait until the temperature drops to room temperature. Adjust the temperature knob again. Calibrate and determine the pH at room temperature.   Experimental results: According to the above method, the pH at 37°C is on average 0.18 lower than the pH at 23°C. The pH is 0.32 lower than the pH at l2℃ on average. Temperature changes have a great influence on the pH of the buffer, so it must be prepared at the operating temperature. Tris-HCl buffer prepared at room temperature cannot be used at 0℃～4 ℃.   Therefore, the pH of the TRIS-HCL buffer is greatly affected by temperature changes. When measured by different methods, the changes are different. The pH changes of the two temperatures (37°C, 23°C) have nothing to do with the measurement method. We speculate that to determine the pH value of a solution at a certain temperature. It is necessary to adjust not only the temperature compensation value of the pH meter but also all the various solutions and distilled water to the measurement temperature.

There are many types of heparin salt blood anticoagulants. Heparin sodium is the most commonly used, but heparin calcium is used in some places. Is there any difference between heparin calcium and heparin sodium in blood anticoagulation?   Heparin sodium is used for anticoagulant drugs and other non-drug reagents such as blood collection tubes or cosmetics. The potency, purity and impurity content of heparin sodium for different purposes are different; while heparin calcium is mainly used for For drugs, the requirements are relatively high.   Heparin sodium and heparin calcium are both used as blood anticoagulants, and the principle of action is similar. Both use heparin to anticoagulate. Unfractionated heparin and low molecular weight heparin can be combined with antithrombin iii to increase the affinity of antithrombin iii and coagulation factors, and play the role of anticoagulation factors.     Low-molecular-weight heparin has two forms, sodium salt and calcium salt, but the clinical efficacy is not much different. Heparin calcium is slightly stronger than heparin sodium in anticoagulant factor 2a, and the anticoagulant effect is relatively weak, but overall there is no significant difference in clinical efficacy.   Heparin sodium is easy to cause subcutaneous hemorrhage when injected subcutaneously, and local stimulation of heparin calcium is slightly lighter than heparin sodium when injected subcutaneously, which can effectively avoid this adverse reaction.   In the beginning, there was only heparin sodium, but later it was discovered that its bioavailability was relatively low, and there would be local adverse reactions. For example, when choosing subcutaneous injections around the umbilical area, ecchymosis may appear. In severe cases, the bioavailability of heparin calcium is relatively high, and the absorption is relatively fast. Local adverse reactions, especially subcutaneous ecchymosis, are relatively rare.   Heparin sodium is generally used for needle sealing for infusion patients, and its effect is quite good. However, when patients choose subcutaneous injection, it is better to choose heparin calcium, so the adverse reactions will be smaller.   Regarding how to choose heparin sodium and heparin calcium, the specific use should be under the guidance of a specialist, and an individualized medication plan should be made according to your own situation. What needs to be reminded is that Desheng brand heparin sodium is not a medicine and cannot be used as a medicine. It can only be used as an anticoagulant for blood testing in blood collection tubes.

Serum separation gel is a viscous fluid with thixotropy. Through centrifugation, the separation gel will form a colloidal isolation layer between blood cells and serum, thereby preventing the mutual diffusion between serum components and blood cells. The layer enables the serum to be analyzed, tested and stored in the original state as much as possible, to ensure the original properties of the blood sample, and thus greatly improve the accuracy of the test results. So, can serum separating gel be applied to those blood collection tubes? Next, the editor of Desheng will answer for everyone.   1. Nucleic acid detection tube. The nucleic acid detection tube is mainly added with EDTA + serum separation gel. It is suitable for the collection, transportation and storage of venous blood samples for nucleic acid detection. It is aimed at DNA amplification detection of HBV DNA, HCV and HIV. The serum separation gel can It can block the interference of hemoglobin in red blood cells on nucleic acid detection experiments   2.The PRP tube, the Chinese name "High Concentration Platelet Plasma", uses serum separation gel to extract platelet richness with precise specific gravity, and then injects it into the part we need, so as to achieve the effect of beauty repair and regeneration or treatment. So the PRP tube is not actually what to check, but to extract high-concentration platelet rich for reuse. 3. CPT tube, also called vacuum mononuclear cell preparation tube, uses different specific gravity of serum separation gel to separate lymphocytes and mononuclear cells from whole blood. It is used in clinical medical testing, mainly for HLA or residual leukemia gene testing, tuberculosis Testing, HIV testing, etc.   4. PST tube is mainly used to separate blood cells and serum, plasma, increase its output, ensure the stability of plasma composition, collect plasma samples, eliminate clotting time, and are mostly used for intensive care and emergency inspections.   Desheng is an established manufacturer of serum separation gel. It has invested heavily in machinery, equipment, production personnel, and R&D and quality inspection. After the continuous improvement of the first, second and third generations, the separation gel has been continuously improved. The separation gel developed and produced belongs to the fourth generation product. It has the advantages of more inert hydrophobic material and suitable for long-term storage of blood. Even if it is in contact with water for a long time, the pH value will not change. Moreover, Desheng's serum separation gel has also gained resistance. The patent of irradiated separation gel, the gold content of this patent is particularly high, welcome to consult and order!

Carbomer is a high-molecular polymer cross-linked with acrylic acid and allyl sucrose ether or allyl pentaerythritol ether. Carbomer’s research began in the 1950s and was first developed and produced by Goodrich in the United States. By the 1970s and 1980s, the research on carbomer became mature and has been widely used, mainly in cosmetics and Pharmaceutical research and production. The following Desheng mainly explains the application of carbomer in bioadhesive drug delivery system.   carbomer gel   When carbomer is an anionic adhesive, it should not be used in combination with divalent basic drugs to avoid precipitation. The bioadhesive drug delivery system (BDDS) acts on various cavity epidermal cell mucosa or skin surface, such as gastrointestinal tract, vagina, oral cavity, nasal cavity, epidermis, etc. The dosage forms are tablets, membranes, and gels. Agent, stick, etc. Among them, gel is a new type of bioadhesive drug release system that has developed rapidly in recent years. It has good dispersion, strong adhesion, good stability, long-lasting drug effect, convenient application, and can avoid the first pass effect and the site of administration. Advantages of high concentration.   (1) Gastrointestinal bioadhesive   Sulpiride skeleton sustained-release retention tablets made of carbomer can adhere to the surface of gastrointestinal mucin or epithelial cells, prolong the retention time and achieve the purpose of sustained release. In vivo studies in rabbits have shown that compared with oral solutions and powder injections, the AUC of the sustained-release retention tablet can be increased by more than 1 time, the mean retention time (MRT) can be extended by 4 to 5 times, and the bioavailability is improved.   (2) Vaginal bioadhesive   Carbomer 974NF was used to make metronidazole liposome and clotrimazole liposome into gel to treat vaginitis. In vitro experiments showed that after 24 hours of release of the two drug-containing liposome gels, approximately 50% metronidazole and 30% clotrimazole remained in the gels. And the stability test shows that Carbomer 974NF can maintain the particle size distribution of two liposomes, indicating that the bioadhesive liposome gel is suitable for local treatment of vaginal diseases. In order to avoid removal of the uterus in patients with uterine cancer, carbomer-based preparations can be administered through the vagina to allow the drug to adhere to the uterine mucosa, kill cancer cells without damaging normal cells, and avoid removing the uterus.   Using an appropriate ratio of hydroxypropyl cellulose (HPC) and carbomer as an adhesive, the bleomycin can be directly pressed into tablets or made into a duckbill suppository, which can be adhered to the cervix, and the preparation remains in its original shape after being taken out after 24 hours. It is speculated that this dosage form can achieve satisfactory results when used in the treatment of uterine cancer.   (3) Oral bioadhesive   The drug can directly enter the systemic circulation after being absorbed by the oral mucosa, avoiding the first pass effect. The felodipine oral mucosal adhesive sheet prepared with hypromellose (HPMC) K4M and carbomer 974P as bioadhesive polymers has an apparent release rate constant of 3.3% h-1, and an average adhesive force of 131.08～181.35g. It has been verified by in vivo experiments that the preparation has a suitable adhesion force to the oral cavity and is less irritating to the oral mucosa. In order to obtain a good treatment of periodontitis, metronidazole oral adhesive tablets were prepared with carbomer 940 and hydroxyethyl cellulose (HEC). When the ratio of the two is 1:1, the drug loading of the product is 20mg. It can be released slowly in the oral cavity, and the drug concentration detected at 12h is higher than the minimum inhibitory concentration.   (4) Bioadhesive for nose   Nasal administration can be aimed at special patients who are inconvenient or difficult to implement oral and intravenous administration. Carbomer 971P was used as an auxiliary material to develop apomorphine nasal powder mist. The sustained release study showed that the bioavailability of this dosage form is equivalent to that of subcutaneous injection, and it has sustained release effect. Najafabadi et al. reported that insulin was made into card Pom gel spray.   Carbomer can be divided into products of various specifications according to the degree of polymerization. The application of products of each specification will vary due to the degree of polymerization and viscosity. Among them, carbomer 934, 940, 941, etc. are the most widely used. . Desheng is one of the manufacturers of Carbomer, which can provide Carbomer 940 and 980, and you can call for consultation if you need it.

We always add buffer solutions when performing DNA electrophoresis. Commonly used buffer solutions include TAE, which contains Tris, acetate and EDTA, and TBE (Tris-borate-EDTA).   What is the role of the buffer? One of the functions of the buffer is to maintain the pH of the solution stable. When an electric current passes through water, an oxidation reaction occurs at the anode to generate oxygen and hydrogen ions; a reduction reaction occurs at the cathode to generate hydrogen and hydroxide ions. Long-term electrophoresis will make the anode acid and the cathode alkaline. A good buffer system should have a strong buffering capacity to keep the pH of the solution at both poles basically stable. Another function of the electrophoresis buffer is to make the solution have a certain conductivity to facilitate the migration of DNA molecules. DNA is an alkaline substance that is negatively charged during electrophoresis (buffer pH=8) and migrates from the negative electrode to the positive electrode.   Another component of the electrophoresis buffer is EDTA, the purpose of which is to chelate Mg2+ plasma and prevent the activation of DNase during electrophoresis. Since nuclease needs these ions, EDTA can hold these ions firmly to avoid nucleic acid degradation. But it should be noted that magnesium ions are also cofactors of many enzymes, such as restriction enzymes, DNA polymerases, etc., so the concentration of EDTA is generally not too high (usually around 1mM). Desheng TRIS buffer packaging So which one is better, TAE or TBE? In fact, which one should I use for DNA electrophoresis? It really depends on the purpose of your experiment. Let's take a look at the difference between the two. 1. The conductivity of TBE is greater than that of TAE. Therefore, compared with TAE, TBE is less likely to cause overheating in the electrophoresis tank. TBE is recommended for long-term electrophoresis.   2. Boric acid is an enzyme inhibitor, so if you need to separate electrophoresis DNA for digestion reaction, it is recommended to use TAE as the electrophoresis buffer solution   3. TBE is better for separating smaller fragments. For fragments smaller than 300bp, the migration speed in TBE is faster on a 2% agarose gel.   4. TAE is suitable for the separation of large fragments. Fragments larger than 2kb migrate faster in TAE (in 0.8% agarose gel), and the speed is about 10% faster than in TBE. TAE is more suitable for recovery of DNA Fragment. Compared with TBE, TAE has higher resolution for supercoiled DNA.   In summary, the question of whether TBE or TAE is better cannot be generalized. The most suitable buffer system should be selected according to the specific experimental purpose. The biological buffer developed by Desheng has a wide buffer range, and only this kind of buffer is used. The system can prepare buffers with a wide range of pH values, and can provide various specifications of packaging. Buy buffers at Desheng Biochemical, welcome to consult and purchase.  

This year’s World Hepatitis Day "Chao Wen Tian Xia" reported a series of astonishing figures: Hepatitis B and C affect 325 million people worldwide. At present, there are about 70 million hepatitis B virus carriers in my country, and about 20-30 million people need treatment. , And only 18% can be diagnosed. These data show that the prevention and treatment of hepatitis B is still a big challenge.   Early screening and diagnosis is the key to effective control of hepatitis B infectious diseases. HBsAg is the first serum marker to appear after hepatitis B virus infection. It has high predictive value and is currently the most clinically used serum marker. It is also recognized by the WHO for judging HBV infection. Key indicators. High sensitivity, high specificity, and quantitative detection are the three major trends in HBsAg detection. Acridine ester chemiluminescence immunoassay has the characteristics of simple luminescence system, no catalyst, high sensitivity and few interference factors. It is widely used in the diagnosis of tumor markers, infectious diseases, especially viral hepatitis.     Some researchers have established a method for detecting HBsAg content in human serum/plasma based on the principle of chemiluminescence immunoquantitative analysis, using acridine ester labeling analysis technology and double-antibody sandwich method. This method uses a two-step method (washing twice). First, the sample is reacted with the biotinylated hepatitis B virus surface antibody (Anti-HBs). If the sample contains HBsAg, it will form an antigen-antibody complex , Adding streptavidin-coated particles, the complex forms a solid phase under the interaction of biotin and streptavidin. Then the reaction solution is placed in a magnetic field, the magnetic particles under test will be adsorbed, and the unbound substances will be washed and removed by washing. Then add the acridine ester labeled Anti. HBs reacts with the HBsAg complex on the magnetic particles, and the unbound substance is washed and removed by washing. Finally, a chemiluminescence buffer is injected to detect the intensity of the chemiluminescence photons, and the light intensity generated is proportional to the concentration of HBsAg in the sample.   The chemiluminescence quantitative detection kit based on the hepatitis B surface antigen acridinium ester chemiluminescence quantitative immunoassay method can be effectively used in the clinical diagnosis of hepatitis B and the dynamic monitoring of the disease. It has high sensitivity, good specificity, accurate quantification, and all performance indicators. It has the advantages of meeting clinical needs, and the price is relatively high in acceptability of imported reagents. It has great potential for large-scale clinical application and is of great significance for the prevention and treatment of hepatitis B.   Desheng is a professional company engaged in the research, development, production, sales and technical services of biochemical reagents, polymer materials and equipment, import and export of goods, technology import and export, and agent import and export. Although there is no ability to produce chemiluminescence quantitative detection kits, it can provide 6 kinds of acridinium ester products (acridinium ester DMAE-NHS, acridinium ester NSP-DMAE-NHS, acridinium salt NSP-SA, acridinium salt NSP-SA-NHS, acridine hydrazide NSP-SA-ADH, acridinium ester ME-DMAE-NHS), as well as the luminescent substrates luminol and isoluminol.

Real-time fluorescent quantitative PCR technology is a leap forward in DNA quantitative technology. It is used to amplify specific DNA fragments, which can be regarded as special DNA replication in vitro. Through the DNA gene tracking system, the virus content in the patient's body can be quickly grasped with an accuracy of nanometer level. The real-time fluorescent quantitative PCR is the carrier to realize this technology.   The PCR laboratory is actually extremely powerful. Qualitative analysis and quantitative detection are its two biggest application directions. In addition to the new crown nucleic acid detection, what else can our "universal" PCR laboratory do? Next, I will show you a few examples of projects with specific application directions, and hope that these examples can provide medical systems at all levels with ideas and directions for project development.     (1) Pathogen determination   The advent of PCR technology enables rapid and convenient pathogen detection. Because the false positive rate of PCR technology is too high, a positive result can be obtained as long as there is a small amount of pathogens, which cannot be used as a diagnostic basis, and it has clinical significance only when a certain number of pathogens exist. Therefore, it is particularly important to accurately quantify the template, and the results can be obtained quickly and accurately by using fluorescent technology PCR. PCR can be used to solve the "window period" of immunological testing, determine whether the disease is in a recessive or subclinical state, and when antibody testing cannot determine whether it is a current infection or a past infection.   (2) Genetic disease detection   Gene mutation and copy number variation are the main genetic basis of genetic disease and the main target of genetic disease detection. The complexity of genetic diseases is accompanied by a large number and wide types of gene mutations; gene copy number variation is not only manifested as deletions and duplications, but also the position, size and replication multiples of the deletions are diverse. The complexity of genetic variation poses a technical challenge for the clinical detection of genetic diseases. Real-time PCR technology is a new generation of real-time PCR technology that we have recently developed. Using fluorescent labeling or melting point analysis, multiple targets can be detected in a single reaction tube.   (3) Personalized medication   The development of pharmacology and pharmacogenomics has clarified the genetic nature of individual differences in drug metabolism and effects. Abnormal drug reactions are mainly caused by mutations in drug metabolizing enzyme genes that lead to abnormal enzyme activity, which in turn leads to the failure of normal metabolism of drugs in the body after taking the drug. Elimination and excretion from the body make the drug concentration in the body too high or too low, and the ideal therapeutic effect cannot be achieved. This kind of abnormal drug reaction can be used to detect genetic genes related to the drugs taken by the patient, adjust the drug dosage or search for alternative drugs, to maximize the formulation of a more reasonable, effective and economical drug treatment plan.