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Description
Human SFRP-2 ELISA KitProduct Specification Usage Experimental equipment required for the experiment: 1. Microplate reader (450nm) 2. High precision pipette and gun tips: 0. 5 10uL, 5 50uL, 20 200uL, 200 1000uL 3. 37 constant temperature box 4. Distilled water or deionized water Sample processing and requirements: 1. Serum: Place the whole blood sample collected in the serum separation tube at room temperature for 2 hours or at 4 overnight, then centrifuge at 1000g for 20
Product Specification
| Usage |
Experimental equipment required for the experiment: 1. Microplate reader (450nm) 2. High-precision pipette and gun tips: 0.5-10uL, 5-50uL, 20-200uL, 200-1000uL 3. 37℃ constant temperature box 4. Distilled water or deionized water Sample processing and requirements: 1. Serum: Place the whole blood sample collected in the serum separation tube at room temperature for 2 hours or at 4℃ overnight, then centrifuge at 1000×g for 20 minutes, and take the supernatant, or store the supernatant at -20℃ or -80℃, but avoid repeated freezing and thawing. 2. Plasma: Collect the specimen using EDTA or heparin as an anticoagulant. Centrifuge the specimen at 1000 × g for 15 minutes at 2-8°C within 30 minutes of collection. The supernatant can be assayed or stored at -20°C or -80°C, but avoid repeated freezing and thawing. 3. Tissue homogenization: Rinse the tissue with pre-chilled PBS (0.01M, pH 7.4) to remove residual blood (lysed red blood cells in the homogenate will affect the measurement results). Weigh the tissue and mince it. Add the minced tissue to the appropriate volume of PBS (generally a 1:9 weight-to-volume ratio, e.g., 1 g of tissue sample to 9 mL of PBS. The specific volume can be adjusted according to experimental needs and recorded. It is recommended to add protease inhibitors to the PBS) in a glass homogenizer and grind thoroughly on ice. To further lyse tissue cells, the homogenate can be sonicated or repeatedly frozen and thawed. Finally, centrifuge the homogenate at 5000 × g for 5-10 minutes, and the supernatant can be assayed. 4. Other biological fluids: Centrifuge at 1000xg for 20 minutes, remove the supernatant, and test. Pre-test preparation: 1. Remove the test kit from the refrigerator 10 minutes in advance and equilibrate to room temperature. 2. Prepare the standard gradient working solution: Add 1 mL of universal diluent to the lyophilized standard, let it stand for 15 minutes to completely dissolve, then gently mix (concentration is 20 ng/mL). Then dilute to the following concentrations: 20 ng/mL, 10 ng/mL, 5 ng/mL, 2.5 ng/mL, 1.25 ng/mL, 0.625 ng/mL, 0.3125 ng/mL, and 0 ng/mL. Serial dilution method: Take 7 EP tubes and add 500 μL of universal diluent to each tube. Pipette 500 μL of the 20 ng/mL standard working solution into the first EP tube and mix thoroughly to make a 10 ng/mL standard working solution. Repeat this procedure for subsequent tubes. The last tube serves directly as a blank well; there is no need to aspirate the liquid from the penultimate tube. See the figure below for details. 3. Preparation of Biotinylated Antibody Working Solution: 15 minutes before use, centrifuge the concentrated biotinylated antibody at 1000×g for 1 minute. Dilute the 100× concentrated biotinylated antibody to a 1× working concentration using universal diluent (e.g., 10µL concentrate + 990µL universal diluent). Prepare immediately before use. 4. Prepare the enzyme conjugate working solution: 15 minutes before use, centrifuge the 100× concentrated enzyme conjugate at 1000×g for 1 minute. Dilute the 100× concentrated HRP enzyme conjugate to a 1× working concentration with universal diluent (e.g., 10 μL of concentrate + 990 μL of universal diluent). Prepare immediately. 5. Prepare the 1× wash solution: Dispense 10 mL of 20× wash solution into 190 mL of distilled water (concentrated wash solution removed from the refrigerator may crystallize; this is normal. Allow to stand at room temperature until the crystals have completely dissolved before preparing). Procedure: 1. Remove the desired strips from the aluminum foil bag after equilibration at room temperature for 10 minutes. Seal the remaining strips in a ziplock bag and return to 4°C. 2. Sample addition: Add 100 μL of sample or standard of varying concentrations to the corresponding wells. Add 100 μL of universal diluent to the blank wells. Cover with a film and incubate at 37°C for 60 minutes. (Recommendation: Dilute the sample to be tested at least 1-fold with universal diluent before adding it to the ELISA plate. This will reduce the impact of matrix effects on the test results. The sample concentration should be multiplied by the corresponding dilution factor when calculating the final sample concentration. It is recommended to run replicates for all test samples and standards.) 3. Add Biotinylated Antibody: Remove the ELISA plate and discard the liquid without washing. Add 100 μL of Biotinylated Antibody Working Solution directly to each well. Cover with a film and incubate at 37°C for 60 minutes. 4. Wash: Discard the liquid and add 300 μL of 1x Wash Solution to each well. Let stand for 1 minute, shake off the wash solution, and pat dry on absorbent paper. Repeat this process three times (a plate washer can also be used). 5. Add Enzyme Conjugate Working Solution: Add 100 μL of Enzyme Conjugate Working Solution to each well. Cover with a film and incubate at 37°C for 30 minutes. 6. Washing: Discard the liquid and wash the plate five times as in step 4. 7. Adding substrate: Add 90 μL of substrate (TMB) to each well, cover with a sealing film, and incubate at 37°C in the dark for 15 minutes. 8. Adding stop solution: Remove the ELISA plate and add 50 μL of stop solution directly to each well. Immediately measure the OD value of each well at a wavelength of 450 nm. Calculating experimental results: 1. Calculate the average OD value of the standard and sample replicates and subtract the OD value of the blank well as a correction factor. Plot the standard curve of the four-parameter logistic function on double-logarithmic graph paper, with concentration as the horizontal axis and OD value as the vertical axis. 2. If the sample OD value is higher than the upper limit of the standard curve, dilute the sample appropriately and retest. Multiply the sample concentration by the corresponding dilution factor. |
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| Theory | This kit uses a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA). Sample, standard, biotin-labeled detection antibody, and HRP conjugate are sequentially added to microwells pre-coated with a Secret Frizzled Related Protein 2 (SFRP-2) capture antibody. After incubation and washing, the sample is developed using the substrate TMB. TMB is converted to blue by HRP peroxidase and to yellow by acid. The intensity of the color is positively correlated with the amount of Secret Frizzled Related Protein 2 (SFRP-2) in the sample. The absorbance (OD) is measured at 450 nm using a microplate reader to calculate the sample concentration. | |||||||||||||||||||||||||||||||||
| Source | Human | |||||||||||||||||||||||||||||||||
| Synonym | Human Secreted Frizzled Related Protein 2 ELISA Kit | |||||||||||||||||||||||||||||||||
| Detection Type | Double antibody sandwich method | |||||||||||||||||||||||||||||||||
| Composition |
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| Background | Secreted frizzled-related protein 2 (sFRP-2) is a protein encoded by the SFRP2 gene in humans. This gene encodes members of the SFRP family that contain a cysteine-rich domain with homology to the putative Wnt-binding site of the Frizzled protein. SFRPs act as soluble regulators of Wnt signaling. Methylation of this gene is a potential marker for the presence of colorectal cancer. | |||||||||||||||||||||||||||||||||
| General Notes | 1. Strictly adhere to the specified incubation time and temperature to ensure accurate results. All reagents must be at room temperature (20-25°C) before use. Refrigerate reagents immediately after use. 2. Improper plate washing may result in inaccurate results. Ensure that all liquid in the wells is aspirated thoroughly before adding substrate. Do not allow the wells to dry out during incubation. 3. Remove any residual liquid and fingerprints from the bottom of the plate, as this will affect the OD value. 4. The substrate developer solution should be colorless or very light in color. Do not use substrate solution that has turned blue. 5. Avoid cross-contamination of reagents and specimens to prevent erroneous results. 6. Avoid direct exposure to strong light during storage and incubation. 7. Do not expose any reagents to bleaching solvents or the strong fumes emitted by bleaching solvents. Any bleaching agent will destroy the biological activity of the reagents in the kit. 8. Do not use expired products, and do not mix components with different product numbers and batches. 9. Recombinant proteins from sources other than the kit may not be compatible with the antibodies in this kit and will not be recognized. 10. If there is a possibility of disease transmission, all samples should be managed properly and samples and testing devices should be handled according to prescribed procedures. |
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| Storage Temp. | If the unopened kit is stored at 4°C, the shelf life is 6 months. | |||||||||||||||||||||||||||||||||
| Test Range | 0.31-20 ng/mL | |||||||||||||||||||||||||||||||||
| Applications | Serum, plasma, tissue homogenates and other biological fluids |
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4.4 ★★★★★
Based on 29 reviews
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Product Reviews
★★★★★ 5
Not very durable
Size: Small - 2 Count (Pack of 1)
I purchased some of these balls a while back and had forgotten how quickly my yorkie puppy was able to destroy them.. I recently ordered some more bc I saw them on sale. I now have another yorkie pup that also loves to play ball. They actually play ball with each other. Within 24 hrs, the balls are fraying and they are getting choked on the fuzzy s off the balls.
I'm not going to bother to return 3 2pks bc they were so cheap. Now I know why.
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Reviewed in the United States on November 9, 2023
★★★★★ 1
This ball seems to be a counterfeit.
Size: Large - 2 Count ( Pack of 1), Size: Large - 2 Count ( Pack of 1)
This ball seems to be a counterfeit and if it is not, it was made not to be played with by animal or human.
In a review I just read, Iduna had posted this:
Iduna
1.0 out of 5 stars Only for the most docile of play
Reviewed in the United States on March 6, 2024
Size: Large - Pack of 2Verified Purchase
I thought it was great that these came in all sizes and bought the large for an urban dog park hoping it would not go through the slats of the fence and bought these as sort of a test before I bought the launcher. While the sizing was great unfortunately each one lasted a little more than half an hour. The rubber sphere part is constructed of two halves and I don't know if there's any sort of sealant between those two halves or if it's just held together by the thin tennis ball type cover but some bouncing off of the turf covered concrete and dog play upon retrieval caused the two rubber halves to separate and a few more tosses led it to quit bouncing and sort of squished together when the dogs grabbed it. That caused the thin tennis ball type material to fray and all was lost.
This post was more than true without any exaggeration. Our dog fetched it in the house and tore it up within 5 mins. The original Chuckit launcher and ball was our first purchase thinking that these would be great balls to replace the Launcher ball which actually lasted our dog about 3 months of constant play and grinding on it (He loved that thing). This one came apart very easily as you can see, but the smell of the broken rubber was extremely solvent smelling (like toluene) of which I have good experience with chemicals like it from the industry in which I worked. Industrial solvents are definitely bad for our pets and that is the smell that comes out of this broken ball even at a distance. It filled our kitchen with the stench. I find this rather suspect when the description says: "this toy is designed with an extra-thick natural rubber core". In any case, the ball fell apart quickly and it is not like the launcher ball at all. I coach tennis and a real tennis ball would be better for our dog than this thing. Broken tennis balls don't smell like that at all and they last much longer and cost the same amount for 3 or 4 vs 2.
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Reviewed in the United States on March 17, 2024
★★★★★ 4
Chuck it Tennis Balls
Size: Large - 2 Count ( Pack of 1)
Aren’t indestructible with Rotties.
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Reviewed in the United States on April 16, 2026
★★★★★ 5
Good price/Good quality
Size: Large - 2 Count ( Pack of 1)
Dog enjoys. Lots of fun.
Holding up well
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Reviewed in the United States on May 10, 2026
★★★★★ 3
Defective seam
Size: Large - 2 Count ( Pack of 1), Size: Large - 2 Count ( Pack of 1)
My dogs love these, defective or not. I have purchased the two ball set this is the 3rd and last time. Each set has had one ball with a defective seam on interior rubber ball which means it splits open on the first squeeze from the dogs.
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Reviewed in the United States on August 5, 2025
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