| Description | The hydroxyl radical (·OH) is the neutral form of the hydroxide ion (OH⁻) and possesses strong oxidizing capacity. Hydroxyl radicals act on biological molecules such as proteins, nucleic acids, and lipids within the body, damaging cellular structure and function, which can lead to The hydroxyl radical (·OH) is the neutral form of the hydroxide ion (OH⁻) and possesses strong oxidizing capacity. Hydroxyl radicals act on biological molecules such as proteins, nucleic acids, and lipids within the body, damaging cellular structure and function, which can lead to metabolic disorders and disease. The hydroxyl radical scavenging capacity is a key indicator of antioxidant ability and is widely used in research on antioxidant health products and pharmaceuticals.Detection Principle: H₂O₂/Fe²⁺ generates hydroxyl radicals via the Fenton reaction. Salicylic acid effectively captures these generated hydroxyl radicals and reacts with them to produce a purple compound, 2,3-dihydroxybenzoic acid. When a substance capable of scavenging hydroxyl radicals is added, it inhibits the formation of this purple product. Therefore, a darker color indicates a higher hydroxyl radical content, and vice versa. The change in absorbance at 520 nm is measured to calculate the sample's hydroxyl radical scavenging capacity.Applicable Samples: Animal and plant tissues, serum (plasma), cells, bacteria, cell culture supernatants, fruit juice, honey, urine, and other samples.P1501782Component48 T96 TStorageP1501782AFerrous Salt10 mL20 mL2-8℃. Store in the dark.P1501782BH₂O₂5 mL10 mL2-8℃. Store in the dark.P1501782CSalicylic Acid10 mL20 mL2-8℃. Store in the dark.Please check the quantities of all components before starting the experiment.An additional 10% of each component is provided beyond the specified volumes for standard curve preparation or preliminary experiments.User-Prepared Instruments and ReagentsTypeNameNotesInstrumentMicroplate ReaderCapable of measuring absorbance at 520 nm.Consumables96-well MicroplateStandard microplate.ReagentsPBS (pH7.4)For washing samples.OthersHomogenizer (for tissue samples), Incubator, Ice Box, Refrigerated Centrifuge, Adjustable Micropipettes and TipsUsing a multi-channel pipette can improve efficiency for large-scale assays.Experimental Procedure1. Reagent PreparationReagent NameReagent PreparationNotesFerrous SaltReady-to-use; Equilibrate to room temperature before use.Store at 4°C protected from light. Corrosive. Use appropriate personal protective equipment.H₂O₂Ready-to-use; Equilibrate to room temperature before use.Store at 4°C protected from light.Salicylic AcidReady-to-use; Equilibrate to room temperature before use.Store at 4°C protected from light. Irritating to skin and mucous membranes. Use appropriate personal protective equipment.2. Sample PreparationNote: Fresh samples are recommended. If not used immediately, samples can be stored at -80°C for one month. To compare the hydroxyl radical scavenging capacity of different samples, the dilution factor must be the same for the same batch of samples, and extracts or drugs should be prepared at the same concentration.2.1 Animal Tissue SamplesWeigh approximately 0.1 g of tissue, add 1 mL of deionized water, and homogenize in an ice bath. Centrifuge at 10,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.2.2 Plant Tissue SamplesWeigh approximately 0.1 g of tissue, add 1 mL of deionized water and grind. Sonicate in an ice bath for 5 minutes (power 20% or 200W, pulse 3s on, 7s off, repeat 30 times). Centrifuge at 10,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.2.3 Cells or BacteriaCollect 5×10⁶ cells or bacteria into a centrifuge tube. Wash with pre-cooled PBS, centrifuge, and discard the supernatant. Add 1 mL of deionized water. Sonicate in an ice bath for 5 minutes (power 20% or 200W, pulse 3s on, 7s off, repeat 30 times). Centrifuge at 10,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.2.4 Serum (Plasma) and Other Protein-Rich or Turbid LiquidsTake 0.1 mL of sample, add 1 mL of deionized water and mix well. Centrifuge at 10,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.2.5 Honey, Urine, and Other Clear Liquids with Low Protein ContentAssay directly.2.6 Extracts or DrugsCan be prepared to a specific concentration, e.g., 0.5 mg/mL.3. Assay Steps3.1 Microplate Reader Preparation: Preheat for at least 30 minutes. Set the wavelength to 520 nm.3.2 Assay System Setup: Perform the following operations in a 96-well plate. The Blank and Standard wells only need to be set up 1-2 times. Each test well requires a corresponding control well.ReagentBlank Well (µL)Standard Well (µL)Test Well (µL)Control Well (µL)Ferrous Salt40404040H₂O₂040400Deionized Water120804080Salicylic Acid40404040Sample0040403.3 Absorbance Measurement: Mix well, incubate at 37°C for 20 minutes. Read the absorbance at 520 nm, recorded as A blank, A standard, A test, and A control respectively.4. Calculation of ResultsBoth the derived formula and the simplified formula provided below are equivalent.4.1 Data ProcessingCalculate ΔA test = A test - A control Calculate ΔA standard = A standard - A blank 4.2 Calculation of Hydroxyl Radical Scavenging RateHydroxyl Radical Scavenging Rate D% = (ΔA standard - ΔA test ) / ΔA standard × 100%5. Representative ResultsExample: 0.1 g of nectarine pulp was taken and assayed according to the procedure using a 96-well plate.Measured: ΔA standard = A standard - A blank = 1.020 - 0.051 = 0.969ΔA test = A test - A control = 0.465 - 0.052 = 0.413Calculated Hydroxyl Radical Scavenging Rate D% = (0.969 - 0.413) / 0.969 × 100% = 57.38%Precautions1. Before formal testing, it is recommended to perform a preliminary test with 2-3 samples expected to have significant differences.2. For tissue samples, cell samples, etc., results can be normalized between samples by measuring protein concentration. Aladdin's BCA Protein Quantification Kit (B665595) or Ready-to-Use BCA Protein Quantification Kit (R1491648) is recommended.3. This kit is compatible with spectrophotometer detection. Adjust the reagent preparation volumes proportionally according to the spectrophotometer's requirements.4. Biochemical reagents are generally irritating and potentially biologically toxic. For your safety and health, implement appropriate biosafety precautions throughout the experiment, including wearing lab coats, masks, gloves, and head covers. Perform experiments in a fume hood or biosafety cabinet.5. This product is for research use only. Not for use in clinical diagnosis.Frequently Asked QuestionsQ: What should I do if the measured ΔA test for the sample is too high or too low?A: If ΔA test < 0.02, appropriately increase the sample volume and re-run the assay. If ΔA test > ΔA standard, further dilute the sample with deionized water or reduce the amount of sample used for extraction, and re-run the assay... Read More | The bacterial viability / toxicity detection kit contains two fluorescent dyes. Nucgreen is a green nucleic acid dye that can stain live and dead bacteria; Ethd III is a red nucleic acid dye that only stains dead bacteria with damaged cell membranes. When nucgreen and ethd III are properly mixed, The bacterial viability / toxicity detection kit contains two fluorescent dyes. Nucgreen is a green nucleic acid dye that can stain live and dead bacteria; Ethd III is a red nucleic acid dye that only stains dead bacteria with damaged cell membranes. When nucgreen and ethd III are properly mixed, the bacteria with intact cell membrane appear green, while the bacteria with damaged cell membrane can appear green and red under different channels, respectively. A common criterion for bacterial viability is the ability to propagate in a suitable nutrient medium, known as a growth assay. This kit is generally in good agreement with the growth assay results in liquid or solid medium. However, under certain conditions, membrane damaged bacteria may recover and propagate in nutrient medium, and such bacteria will be identified as dead bacteria in this assay. On the contrary, some bacteria with intact membranes may not be able to propagate in nutrient medium, but will be recognized as viable bacteria in this assay. Therefore, if there is a large difference between the test results of this kit and the bacterial growth assay, the above possibilities should be considered. Component： Product parameters： NucGreen: Ex/Em = 503/530 nm (结合 DNA)；EthD-III: Ex/Em = 530/620 nm (结合 DNA)。Usage:1 Preparation of control samples for live and dead bacteria (optional)1. Cultivate 4 mL of bacteria in liquid medium until late logarithmic phase.2. Prepare two 1 mL bacterial solutions in an EP tube and centrifuge for 10-15 minutes under 5000-10000 g conditions.3. Remove the supernatant and add 0.3 mL of 0.85% NaCl resuspended bacteria to one of the EP tubes, and 1 mL of 0.85% NaCl resuspended bacteria to the other tube.4. Add 0.7 mL of isopropanol to a tube containing 0.3 mL of 0.85% NaCl, and mix thoroughly (with a final concentration of 70% isopropanol) to prepare a dead bacterial sample.5. Incubate the two samples at room temperature for 1 hour and mix every 15 minutes.6. Centrifuge the two samples at 5000-10000 g for 10-15 minutes.7. Remove the supernatant, add 1 mL of 0.85% NaCl to resuspend the bacteria in both samples, and centrifuge again as in step 6.8. Use a spectrophotometer to measure the absorbance values (OD670) of two bacterial suspensions at 670 nm.9. Adjust the density of the two bacterial suspensions (live and dead) to 108 bacteria/mL (OD670 ≈ 0.3), and then dilute with 0.85% NaCl at 1:100 to achieve a final density of 106 bacteria/mL.10. Mix two bacterial suspensions as shown in the table below to obtain the required live cell ratio: dead cell ratio.Table 1 Mix live and dead bacterial suspensions by a certain volume to achieve the required ratio of live and dead cellsLive cells: Dead cellsVolume of viable bacterial suspension（mL）Volume of dead bacterial suspension（mL）0:10001.010:900.10.920:800.20.830:700.30.750:500.50.5100:01.00II Staining methods for fluorescence microscopy observation1. Mix 1 volume of component A, NucGreen, and 2 volumes of component B, EthD-III, in a microcentrifuge tube. After thorough mixing, add 8 volumes of 0.85% NaCl solution to obtain a 100 x dye solution.2. Every 100 µ L bacterial suspension, add 1 µ 100 x dye solution of L.3. Mix thoroughly and incubate at room temperature in the dark for 15 minutes.4. Take 5 µ The bacterial suspension after L staining was dropped onto a glass slide with an 18 mm square cover glass.5. Observe under a fluorescence microscope. The fluorescence of live and dead bacteria can be observed simultaneously under any standard FITC long-acting filter. Alternatively, live (green fluorescent) and dead (red fluorescent) bacteria can be observed using FITC and Cy3 (or Texas Red) channels, respectively.Attention: (1) Before staining bacteria, attention must be paid to removing residues of growth media. Nucleic acid and other media components can bind to NucGreen and EthD-III dyes in some way, resulting in unacceptable staining changes. A simple washing step is usually sufficient to remove interfering media components from bacterial suspension. It is not recommended to use phosphate buffer solutions as they can reduce staining efficiency. (2) Before starting the formal experiment, the dye concentration should be adjusted to distinguish between NucGreen labeling live bacteria and EthD-III labeling dead bacteria. The optimal concentration may vary depending on the bacterial strain. It is generally best to use the lowest dye concentration that can provide sufficient signal. The above conditions have been optimized for staining live/dead cells of Escherichia coli.III Before starting the staining method experiment of flow cytometry, please read the precautions under the fluorescence microscope staining steps.According to Table 1, add 11 different proportions of live and dead bacteria to the EP tube. Each of the 11 samples has a volume of 1 mL.2. Add 12 µ The A component of L, NucGreen, and 24 µ The B component EthD-III of L was mixed in a microcentrifuge tube. Add 3 to each of the 11 samples µ Mix the mixed dyes of L thoroughly by blowing them up and down several times. (Note: Additional control bacterial samples need to be prepared for separate NucGreen and EthD-III staining)3. Incubate at room temperature in the dark for 15 minutes.4. Analyze each sample using a flow cytometer, detect NucGreen positive cells using FITC channels, and detect EthD-III positive cells using PI or PE channels.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. if the orifice plate is used for detection, a small amount of bacterial liquid can be left for imaging after standing for 10 min, which can effectively reduce the background. 3. in order to be closer to the real results, it is recommended to keep the brightness of red fluorescence consistent with that of green fluorescence in merge pictures. 4. fluorescent dyes have quenching problems. Please try to avoid light during experimental operation to slow down fluorescence quenching. 5. for your safety and health, please wear experimental clothes and disposable gloves.Scope of application：Staining of dead and live bacteria... Read More | Product introduction：Product introduction：Cell Cycle Assay Kit Plus ( Cell Cycle Assay Kit Plus ) has certain applicability for live cells and fixed cell cycle detection. For different types of cells, whether it is applicable or not needs to be determined after testing. Cell Cycle Product introduction：Product introduction：Cell Cycle Assay Kit Plus ( Cell Cycle Assay Kit Plus ) has certain applicability for live cells and fixed cell cycle detection. For different types of cells, whether it is applicable or not needs to be determined after testing. Cell Cycle Assay Kit Plus ( Cell Cycle Assay Kit Plus ) uses RedNucleus I staining to detect cell cycle. RedNucleus I is a far-infrared nucleic acid dye with cell membrane permeability, which can quickly enter living cells, specifically bind to DNA, and perform cell cycle detection on living cells without RNase digestion. Compared with the traditional PI staining method, the cells do not need to be broken or fixed, and the operation is simpler. RedNucleus I is a fluorescent dye of double-stranded DNA, and the fluorescence intensity after binding to double-stranded DNA is proportional to the content of double-stranded DNA. The intracellular DNA content can be measured by flow cytometry, and then the cell cycle analysis can be carried out according to the distribution of DNA content. After RedNucleus I staining, assuming that the fluorescence intensity of G0 / G1 phase cells is 1, the theoretical value of the fluorescence intensity of G2 / M phase cells containing two copies of genomic DNA is 2, and the fluorescence intensity of S phase cells undergoing DNA replication is between 1-2. In addition, RedNucleus I is compatible with dyes such as Horizon BV / BUV, FITC and R-PE, and can be periodically detected after sample staining.The kit is usually used to detect the cell cycle of cultured adherent or suspended cells. If it is used for cell cycle detection of tissues, the tissues must be digested into a single cell state.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. this product is applicable to the detection of living cells and fixed cell cycle with certain limitations. Whether it is applicable to different types of cells needs to be determined after testing. If fixation is needed, it is recommended to use ice bath pre cooling 75-80% ethanol -20 ℃ to fix cells overnight. 3. fluorescent dyes have quenching problems. Please try to avoid light during storage and use to slow down fluorescence quenching. 4. for your safety and health, please wear experimental clothes and disposable gloves.Instruction： Experimental materials ( self-provided )：①cell lines or other cell samples ( self-prepared ) ；②This kit ; ③ trypsin ( self-prepared ) ;④ Cell culture medium containing FBS ( self-prepared ) ; Experimental procedure： 1.Preparation of cell samples : ( 1 ) ( This step is for adherent cells, if suspended cells, can be carried out directly step ( 2 ) ) Digest cells with trypsin, add cell culture medium, gently blow away cells, collected into the centrifuge tube. Note : The number of cells on the machine needs to reach 50,000 and above, so the initial number of cells collected needs to be sufficient. ( 2 ) Centrifuged about 1000 g for 3-5 min to precipitate cells. Carefully remove the supernatant, add about 1 mL of ice bath pre-cooled 1 × staining buffer ( 10 × staining buffer diluted with diH2O at 1 : 10 ), re-suspend the cells. Repeat once. ( 3 ) Centrifuged about 1000 g for 3-5 min to precipitate cells. After the supernatant was discarded, 1 mL of culture medium was added to re-suspend the cells ( for fixed cells, 1 × PBS can also be used to re-suspend ). Gently flick the bottom of the centrifuge tube to properly disperse the cells to avoid cell aggregation. 2.Staining : 4 µL of RedNucleus I staining solution was added to each tube of cell samples, slowly and fully mixed, and incubated at room temperature in dark for 20 min ( or incubated at 37 ° C in dark for 5-10 min ). The optimal incubation time of different cells is different, and the staining time can be adjusted and optimized according to the actual staining effect to obtain a more ideal staining effect. 3.Flow cytometry detection and analysis : Excited at 638 nm by flow cytometry, it is recommended to detect in RL3 or FL4 channels, or use RL1 and RL2 channels. Cell DNA content analysis and light scattering analysis were performed using appropriate analysis software.Scope of application：Cell cycle detection... Read More | Inquire | DescriptionMaterials included in the kit are designed to be used with the Hy-Energy′s PCTPro-2000 System. They also can be used for demonstration purposes and as standards during the development of novel hydrogen storage and battery materials |