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Description
Human POSTN 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: 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: 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. Plasma: Collect specimens using EDTA or heparin as anticoagulants and centrifuge them at 1000×g for 15 minutes at 2-8℃ within 30 minutes of collection. The supernatant can be tested or stored at -20℃ or -80℃, but repeated freezing and thawing should be avoided. 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 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 utilizes 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 periostin (POSTN) capture antibody. After incubation and washing, the sample is developed using the substrate TMB. TMB converts to blue under the catalysis of peroxidase (HRP) and to yellow under the action of acid. The intensity of the color is positively correlated with the amount of periostin (POSTN) in the sample. The absorbance (OD) is measured at 450 nm using a microplate reader to calculate the sample concentration. | |||||||||||||||||||||||||||||||||
| Source | Human | |||||||||||||||||||||||||||||||||
| Synonym | Human Periostin ELISA Kit | |||||||||||||||||||||||||||||||||
| Detection Type | Double antibody sandwich method | |||||||||||||||||||||||||||||||||
| Composition |
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| Background | Periostin (POSTN, PN, or osteoblast-specific factor OSF-2) is a protein encoded by the POSTN gene. Periostin acts as a ligand for α-V/β-3 and α-V/β-5 integrins, supporting epithelial cell adhesion and migration. Periostin, a vitamin K-dependent factor of enamel structure, is a secreted extracellular matrix protein originally discovered in mesenchymal lineage cells (osteoblasts, osteoblast-derived cells, periodontal ligament, and periosteum). It has been implicated in epithelial-mesenchymal transition in cancer and mesenchymal differentiation in the developing heart. The protein shares homology with Fasciclin I, a secreted cell adhesion molecule found in insects. In many cancers, periostin binds to integrins on cancer cells, activating Akt/PKB and FAK-mediated signaling pathways. This leads to increased cell survival, invasion, angiogenesis, metastasis, and epithelial-mesenchymal transition. In humans and mice, periostin undergoes alternative splicing at its C-terminal region, generating specific isoforms that are observed in a wide range of cancers, including pancreatic, colon, and breast cancer. While collagens play a wide range of roles in tissue development and disease, their function in tissue remodeling in response to injury is a fundamental common role among these diverse mechanisms. Periostin is temporally upregulated during changes in cell fate, both physiologically and pathologically. It influences extracellular matrix reorganization, tissue remodeling, and epithelial-mesenchymal transition, all of which may be relevant to tissue healing, development, and disease. Thus, it functions as a mediator, balancing appropriate and inappropriate responses to tissue injury. | |||||||||||||||||||||||||||||||||
| 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 | 0.15-10 ng/mL | |||||||||||||||||||||||||||||||||
| Applications | Serum, plasma, and other biological fluids |
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4.5 ★★★★★
Based on 10 reviews
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Product Reviews
★★★★★ 4
Decent, definitely got the job done
Size: X-Large, Color: Light Grey Heather, Size: X-Large, Color: Light Grey Heather
The came out to be a pretty decent quality for the price. Was going to a polo match and just needed something to creat on for my date
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Reviewed in the United States on April 1, 2026
★★★★★ 5
An Extinct Breed - Get before they are gone
Size: Medium, Color: Red
In my day polos used to be soft thick 100 % cotton with generous sleeves covering the upper arm till above the elbows and collars standing high and grand and covering the back of the neck till below the hairline. They had substantial structure/body (shape that held) and ultra comfortable soft cotton. This was my go to piece of clothing to step out in (as opposed to round neck collarless T-Shirts that I wore only at home or for sporting activities).
However, this simple good thing was not to be taken for granted. As time went by, I watched in horror this simple evergreen staple slowly vanish - being replaced by plastic, toxic, carcinogenic trash (synthetic, polyester, 'performance', 'hi-tech') being passed as clothing riding solely on deceptive/misleading/convincing marketing and rapidly transient 'fast fashion trends'. These pieces of junk being passed as 'performance polos'/'hi-tech' had no 'body', clung to your skin like plastic, caused my sensitive skin to itch, with arms so short as if there was shortage of clothing material in the world and were of such thin cheap uncomfortable material that I would wonder how in the world do people put these on their bodies.
The 'trend' continued ...
Fast forward to the present day, finding the 'cotton polo of my youth' is like finding a dinosaur. The polo I grew up with is practically extinct - replaced by trash made with ever cheaper feeling and more toxic materials. Its a win win for the corporates/brands - cheap synthetic lab created materials astronomically marked up (riding on advertisement) - filling the corporate pockets unlike never before and successfully 're-programming' the minds and purchasing behavior of the new generation to accept, get used to, and even get addicted to such toxic 'hi-tech' trash. As for the manufacturing ? No problem - hire some MBA's (with zero knowledge/passion for good quality textile/garment manufacturing) - their sole purpose to be 'maximizing profits' for the next 'earnings report' and they would find the 'cheapest' offshore factory to outsource the manufacturing to. This being a continuous process - if you get a cheaper bid from another factory, just switch to it. No wonder you can never get consistent material, sizing, quality for the exact same product purchased even months apart.
Not just that - even brands that sold fantastic quality 100 % cotton polos at a very reasonable price like Tommy Hilfiger etc went STEEP DOWNHILL. A Tommy Hilfiger polo being sold today is NOWHERE NEAR anything like the quality they had even a few years ago (even though still being theoritically 100 % cotton, the quality (material, cut) now is absolutely junk - in fact they went from being my favorite Polo Shirts (thick, soft, cloud like cotton with generous neck and sleeves and amazing body, texture and shape and in high quality colors and finish) to absolutely shockingly unwearable pieces of garbage (thin, rough, itchy cotton with skimpy sleeves and flat collars and dull cheap finsih and colors with NO lusture, body whatsoever).
I always wish I had seen this day come. I would have stocked up on a lifetim's supply of 'real' clothing when they were still available.
Given the above, I am extremely surprised (pleasantly) by this Amazon Essentials Cotton Polo. This is 100 % cotton, has generous non-skimpy sleeves and has decent material and shape reminiscent of the 100 % cotton polo I am habituated to from my time. Quality of material wise - it is about 65% - 70% of the cotton polos of yesteryears - BUT - even THAT - is like finding diamond (or a dinosaur) in these abhorrent-clothing-times for the 100 % cotton polo lover.
Get this before the 'real cotton polo' is gone for good. I think I may be getting a few.
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Reviewed in the United States on August 10, 2022
★★★★★ 5
Love these polos
Size: Large, Color: Olive
Nice material, fits true to size, colors are nice. Great work shirt in an office setting.
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Reviewed in the United States on June 4, 2026
★★★★★ 3
Sometimes Good, Sometimes Not So Good...
Size: X-Large, Color: Aqua
I've bought several of these shirts in the past, and I've always been very happy with them, right up until my latest purchase. Apparently, depending on which color/style you choose, the shirts may be manufactured in a completely different country. And despite Amazon's efforts to make sure their clothing brands have consistent sizing across the board, it's now clear to me that some of those countries are not on the same page. Case in point: Guatemala.
My latest Amazon Essentials polo shirt purchases consisted of the colors 'light yellow' and 'rust'. Now, the light yellow shirt seems fine. Maybe a tiny bit smaller than my previous shirt purchases, but nothing major. (I think it says made in Chihuahua - but it's hard to tell.) However, the rust colored shirt is drastically smaller than all my similar-sized Amazon polo shirts. I bought it in size Large, but the shirt tail alone is nearly four inches shorter than my previously purchased Amazon Essentials polo shirts. And while the Large-sized Amazon polo shirts normally fit me quite comfortably, with a little bit of room to spare, this rust-colored shirt is skin-tight. If I didn't know any better, I'd swear it was a size Medium masquerading as Large.
All of my previous shirt purchases (I now realize) are labeled as being made in either Madagascar or Vietnam. Those are great. They fit wonderfully. But this new rust-colored shirt (once again, same brand - Amazon Essentials) is labeled as made in Guatemala. And let me tell you, the factory in Guatemala is not on the same page as the factory in Madagascar. Not even close.
So yeah, these are great shirts. So long as you happen to buy the colors/styles that are being made in Madagascar or Vietnam. But buyer beware if you happen to get one from the factory in Guatemala, because those guys are using a whole different set of rulers over there. And unfortunately, there's no way to tell until it arrives on your doorstep.
I'm normally a big fan of Amazon brand products. But this experience has made me quite a bit more wary about buying their clothing items in the future. It really is so very important that their brands have consistent sizing across all colors and styles.
P.S. I actually bought the rust-colored shirt TWICE, because I at first assumed I must have gotten a mislabeled product. But, nope. Both rust-colored shirts are the same, drastically-smaller size, and both are labeled made in Guatemala.
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Reviewed in the United States on June 9, 2020
★★★★★ 5
Great
Size: Large, Color: Burgundy
Nice quality, great fit. Love the pique knit.
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Reviewed in the United States on May 26, 2026