Does filtering work? Yep, lab tested....
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@damic it’s a great question and using a .1um filter can disrupt certain peptides.
Size Exclusion via Aggregation: If individual peptide molecules clump together into larger micro-aggregates or complexes, those clumps may be trapped by the 0.1 µm pores.
High Shear Stress: Pushing a small volume through an ultra-fine 0.1 µm syringe filter requires high pressure, which can occasionally induce foaming or surface-induced denaturation in fragile, large-chain polypeptides.
Recommendations for HandlingPore Size Standard: A standard 0.22 µm filter is typically used for sterile filtration in peptide workflows, as it removes bacteria effectively while reducing resistance and adsorption risks compared to a 0.1 µm filter.Membrane Choice: Use low-binding membrane materials like PES (polyethersulfone) to minimize how much of the peptide sticks to the filter disc.
Had no idea glad I didn’t jump the gun on this one. Makes sense at some point a finer filter is going to disrupt the good stuff in an attempt to get rid of the bad stuff.
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@damic it’s a great question and using a .1um filter can disrupt certain peptides.
Size Exclusion via Aggregation: If individual peptide molecules clump together into larger micro-aggregates or complexes, those clumps may be trapped by the 0.1 µm pores.
High Shear Stress: Pushing a small volume through an ultra-fine 0.1 µm syringe filter requires high pressure, which can occasionally induce foaming or surface-induced denaturation in fragile, large-chain polypeptides.
Recommendations for HandlingPore Size Standard: A standard 0.22 µm filter is typically used for sterile filtration in peptide workflows, as it removes bacteria effectively while reducing resistance and adsorption risks compared to a 0.1 µm filter.Membrane Choice: Use low-binding membrane materials like PES (polyethersulfone) to minimize how much of the peptide sticks to the filter disc.
Had no idea glad I didn’t jump the gun on this one. Makes sense at some point a finer filter is going to disrupt the good stuff in an attempt to get rid of the bad stuff.
@Stevepep Thank you for running AI for us, but the way you presumably constructed your question predisposed the positive answer. If you ask: Will using 0.1 µm syringe filter be significantly more harmful for filtering small peptides solutions comparing to 0.22 µm filter made with the same low-binding hydrophilic membrane like PES?, you may get a different answer.
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@Stevepep Thank you for running AI for us, but the way you presumably constructed your question predisposed the positive answer. If you ask: Will using 0.1 µm syringe filter be significantly more harmful for filtering small peptides solutions comparing to 0.22 µm filter made with the same low-binding hydrophilic membrane like PES?, you may get a different answer.
@vpeptides Side note. I hate AI. It creates stupid people ignorant of their own ignorance. (No I'm not saying Stevepep is stupid. Just making a general statement about what I see in the real world work environment, etc). I get this 10 times a day as an IT director from users entering our response to a helpdesk ticket into AI. "Fine then....fix it yourself!" lol!
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@vpeptides Side note. I hate AI. It creates stupid people ignorant of their own ignorance. (No I'm not saying Stevepep is stupid. Just making a general statement about what I see in the real world work environment, etc). I get this 10 times a day as an IT director from users entering our response to a helpdesk ticket into AI. "Fine then....fix it yourself!" lol!
@jamiegallien AI is OK as long as you clearly realize it is NOT A PERSON, it's a tool that works as a fishing rod, so it all depends how and where you cast it, what bait you use, how deep you will let your line go, how fast you will pull, etc. You may get a different fish, or no fish at all.
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50count@$57.29 +tax,shpg
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@Stevepep Thank you for running AI for us, but the way you presumably constructed your question predisposed the positive answer. If you ask: Will using 0.1 µm syringe filter be significantly more harmful for filtering small peptides solutions comparing to 0.22 µm filter made with the same low-binding hydrophilic membrane like PES?, you may get a different answer.
@vpeptides I am no expert in this area and have no care either way what the correct answer is but they both essentially say the very same thing.
tertiary-structured proteins, highly fragile or complex peptide assemblies could theoretically be disrupted
Bottom line people can use whatever filter they want. I have no horse in this race. AI on peptides sucks because much of the generated information is old and wrong and compiled by people like you and I who know enough to be dangerous.
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@vpeptides I am no expert in this area and have no care either way what the correct answer is but they both essentially say the very same thing.
tertiary-structured proteins, highly fragile or complex peptide assemblies could theoretically be disrupted
Bottom line people can use whatever filter they want. I have no horse in this race. AI on peptides sucks because much of the generated information is old and wrong and compiled by people like you and I who know enough to be dangerous.
@Stevepep I agree. Still, the length of even a long 191 AA polypeptide (HGH) if unrolled in a line is about 67 nm (but it's usually rolled into 5 nm 3D structure), other peptides are much smaller. So even 0.1um (i.e. 100 nm) filter is theoretically fine if it is a low-binding material. Just do it slowly. But those Mycoplasma contaminants also don't scare me too much, it's a minor threat. So, I guess I don't care much either.
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@Stevepep I agree. Still, the length of even a long 191 AA polypeptide (HGH) if unrolled in a line is about 67 nm (but it's usually rolled into 5 nm 3D structure), other peptides are much smaller. So even 0.1um (i.e. 100 nm) filter is theoretically fine if it is a low-binding material. Just do it slowly. But those Mycoplasma contaminants also don't scare me too much, it's a minor threat. So, I guess I don't care much either.
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This post is deleted!
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@vpeptides I am no expert in this area and have no care either way what the correct answer is but they both essentially say the very same thing.
tertiary-structured proteins, highly fragile or complex peptide assemblies could theoretically be disrupted
Bottom line people can use whatever filter they want. I have no horse in this race. AI on peptides sucks because much of the generated information is old and wrong and compiled by people like you and I who know enough to be dangerous.
@Stevepep It's a non issue anyway just from a numbers standpoint. A 0.1 micron filter pore can pass compounds with a molecular weight rating of about 1 million Daltons. The larger peptides we use such as GLP's are ~6000 Daltons. Anything bigger than that is no longer a peptide but is a protein (insulin 5800Da, HGH~22000Da, etc). TRT and such are even smaller.
Stripping the peptide from the solution would happen with nylon or cellulosa based filters (these are PES and chemically modified specifically to allow peptides to pass), extreme pressure (why I tell people to take up to 1 min to filter 3ml - not necessary but a safe number), or if the reconstituted solution is clotted (cloudy and I won't use anyway). Also running a bit of bac only through the filter before introducing the peptide "wets" the filter so you aren't using peptide solution to do that, which would waste a small amount.
Hope this helps.
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Good info. Thanks.
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You guys are much more informed than I am on this topic. Curious - if there were mycoplasma (or any other biological contamination) in these lyophilized powders that were destroyed during the lyophilization process, would the remains be considered endotoxins? Is there any filter that will get rid of those? Without damaging the peptides, of course?
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50count@$57.29 +tax,shpg
I placed an order from them but unfortunately they don’t actually have them in stock. They expect to get it in September. I asked them to cancel my order.
denti
Thanks, they did not indicate on my order that it would take that long to receive them.
All of the other vendors I checked actually disclosed that they were resellers for this item. Also, one of the other vendors said it was only a week delay on the order, so maybe it doesn't take two months.
Novatech had the best prices, however, so I may wait it out.If you find someone who stocks them, please let us know.
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I just placed an order here, not sure how long it will take yet. I’ll keep you updated. But they have free shipping. I’ve ordered from them before, not medical related and they shipped quickly.
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@vpeptides - correct. 0.22 µm (220 nanometers) is the standard pore size used for laboratory sterile filtration. Anything else is overkill from a sterility standpoint.
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@vpeptides - correct. 0.22 µm (220 nanometers) is the standard pore size used for laboratory sterile filtration. Anything else is overkill from a sterility standpoint.
@Blueeyedme
Maybe not if the rat's bbb is not intact.
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