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Description
Human StAR ELISA KitProduct Specification Usage Required experimental equipment: 1. Microplate reader (450nm) 2. High precision pipettes and pipette tips: 0. 5 10uL, 5 50uL, 20 200uL, 200 1000uL 3. 37C incubator 4. Distilled or deionized water Sample preparation and requirements: 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 and
Product Specification
| Usage | Required experimental equipment: 1. Microplate reader (450nm) 2. High-precision pipettes and pipette tips: 0.5-10uL, 5-50uL, 20-200uL, 200-1000uL 3. 37°C incubator 4. Distilled or deionized water Sample preparation and requirements: 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 and mince the tissue. Add the minced tissue to the appropriate volume of PBS (generally a 1:9 weight-to-volume ratio, e.g., 1g of tissue sample to 9mL 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 freeze-thawed. Finally, centrifuge the homogenate at 5000×g for 5-10 minutes and remove the supernatant for analysis. Cell culture supernatant: Centrifuge at 1000×g for 20 minutes. Remove the supernatant for analysis or store at -20°C or -80°C, but avoid repeated freeze-thaw cycles. Preparation for Assay: 1. Remove the reagent kit from the refrigerator 10 minutes in advance and equilibrate to room temperature. 2. To 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 10 ng/mL). Then dilute to the following concentrations: 10 ng/mL, 5 ng/mL, 2.5 ng/mL, 1.25 ng/mL, 0.625 ng/mL, 0.3125 ng/mL, 0.15625 ng/mL, and 0 ng/mL. Serial dilution method: Take seven EP tubes and add 500uL of universal diluent to each. Pipette 500uL of the 10ng/mL standard working solution into the first EP tube and mix thoroughly to make a 5ng/mL standard working solution. Repeat this procedure for subsequent tubes. The last tube serves as a blank well; there is no need to pipette liquid from the penultimate tube. See the figure below for details. 3. Preparation of biotinylated detection antibody working solution: Centrifuge the concentrated biotinylated antibody at 1000×g for 1 minute 15 minutes before use. Dilute the 100× concentrated biotinylated antibody to a 1× working concentration with universal diluent (e.g., 10uL concentrate + 990uL universal diluent). Prepare and use immediately. 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 capture antibody against steroidogenic acute regulatory protein, mitochondrial (StAR). After incubation and washing, the sample is developed using the substrate TMB. TMB converts to blue under the catalysis of HRP and to yellow under the action of acid. The intensity of the color is positively correlated with the amount of steroidogenic acute regulatory protein, mitochondrial (StAR) in the sample. The absorbance (OD) is measured at 450 nm using a microplate reader to calculate the sample concentration. | |||||||||||||||||||||||||||||||||
| Source | Human | |||||||||||||||||||||||||||||||||
| Synonym | Human Steroidogenic acute regulatory protein, mitochondrial ELISA Kit | |||||||||||||||||||||||||||||||||
| Detection Type | Double antibody sandwich method | |||||||||||||||||||||||||||||||||
| Composition |
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| Background | The steroidogenic acute regulatory protein (StAR) is a transport protein that regulates cholesterol transfer within mitochondria, the rate-limiting step in steroid hormone production. It is primarily found in steroid-producing cells, including theca cells and corpus luteum cells in the ovary, Leydig cells in the testis, and cell types in the adrenal cortex. | |||||||||||||||||||||||||||||||||
| 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 | 0.156-10 ng/mL | |||||||||||||||||||||||||||||||||
| Applications | Tissue homogenate, cell culture supernatant |
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★★★★★ 5
Best pillow ever!
Size: King (2 Pack)
I love this pillow. I like a softer pillow and my partner prefers a firmer pillow. With these pillows you can adjust it to the comfort level you desire. For mine I took out quite a bit of the shredded memory foam (I call it fluff). I took out one 13 gallon trash bag of the fluff. After I slept on my pillow for a couple of weeks I found it was getting to soft so I took my saved bag of fluff and added it into the pillow. Now it's PERFECT! The cooling side works great. When you lay your head down on it you can feel the cool pillow. Helps falling a sleep easier. I would highly recommend this pillow!
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Reviewed in the United States on May 3, 2026
★★★★★ 5
Great Pillows for a Good Night’s Sleep
Size: Queen (2 pack), Size: Queen (2 pack)
These pillows are very comfortable and supportive. They keep their shape well and provide great neck and head support throughout the night. The material feels soft and high quality, and they helped improve my sleep. I wake up without neck pain and feel well rested. Definitely worth it.
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Reviewed in the United States on January 25, 2026
★★★★★ 5
Great quality for the price
Size: Queen (2 pack)
Wow! For the cost...these pillows are amazing! Comfortable, soft, supportive, and adjustable to your specific needs. Highly recommend, I would buy them again! 10/10
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Reviewed in the United States on May 22, 2026
★★★★★ 5
BEST PILLOW EVER! - But you must follow these instructions
Size: Queen (2 pack)
This is literally the BEST pillow I've ever slept on! It is SO COMFORTABLE, and I can't believe it was $40 for TWO PILLOWS! I slept on a similar, much more expensive name-brand pillow at my friend's house and thought, "I just HAVE to have this pillow!" When I found this one on Amazon for just $20 a pillow, I was so stoked! However, I was turned off by the "paint-like smell" when I slept on it right out of the box the first night. (I was too impatient to try it out!) Do NOT buy this pillow if you're in a hurry, because to get the paint smell to go away, you MUST follow these instructions: 1. Take the pillow out of its case and wash the case. 2. Leave the case off for TWO WEEKS (yes, you heard right!) to let the pillow out-gas. After waiting for two weeks, the smell will be GONE! Yes, I know it's a long time to wait, but it's WORTH IT! As far as the firmness of the pillow is concerned, I took about five big handfuls of the stuffing out and put it in a ZipLoc bag, but my husband liked the pillow as-is. I personally didn't want it so stuffed and wanted a bit "softer" feeling. I also sleep on my stomach sometimes, so taking out five handfuls of stuffing was perfect. I LOVE MY NEW PILLOW! (One thing I wish, however, is that the pillow came in a standard size. My husband and I have queen-size pillow cases, but our kids have standard-size pillow cases. Darn! I want THEM to have a chance to have such a comfy and inexpensive pillow too!)
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Reviewed in the United States on February 10, 2026
★★★★★ 4
The cold side really works. It's nice ;)
Size: King (2 Pack)
The soft side aspect of it is really awesome. We like the whole cold pillow thing but personally I feel like it keeps my head too high up so I wake up with a neck pain. But for someone who likes support, this would be a perfect option.
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Reviewed in the United States on March 14, 2026