Ampure versus Ampure XP

[nextgen]

Ampure

Ampure is just more expensive. Some of the time saved is just from reducing drying time. I think PCRClean is better in terms of band tightness.

thanks, the info helps a lot.

If anyone knows of any info about XP it would be helpful, such as if bead size or surface area of binding is larger than that of regular Ampure, or how binding chemistry is faster now?

[greigite]

I don't know how the chemistry differs, but a rep told me the main difference between the kits is a longer shelf life for XP (1 yr versus 6 mo for regular).

thanks, the info helps a lot.

If anyone knows of any info about XP it would be helpful, such as if bead size or surface area of binding is larger than that of regular Ampure, or how binding chemistry is faster now?

[seqgirl123]

thanks, the info helps a lot.

If anyone knows of any info about XP it would be helpful, such as if bead size or surface area of binding is larger than that of regular Ampure, or how binding chemistry is faster now?

[ECO]

Great questions. Many of these questions are answered in the original patents (the main one is attached...I really like http://patentstorm.us for a free source of patents if you need more).

PEG and some combination of high salts (based on the patent...most likely ~10-15% PEG6-8k, + 1-1.5M NaCl + some divalents) precipitates nucleic acids (and some other molecules)...directly onto the bead surface (which is carboxylated).

It's a very old technique to PEG precipitate via traditional centrifugation, the beads just allow you to avoid spinning by acting as nucleation sites for the precipitation.

As far as the exact chemical differences between standard and XP, I don't know.

[seqgirl123]

Does anyone use Ampure (aka SPRI) in their library prep to replace the other types of PCR purification methods? Ampure XP is a newer version of the existing Ampure, supposed to be faster cleanup.

I cannot find a good text description that will answer these questions. Does anyone know?

1) what is the Ampure buffer made of ?
2) what are the beads made up of? are they of a polymer substance?
3) how does the DNA bind to the beads and then to the magnet? (all I know is that probably the positive charge on the beads bind the negatively charged DNA, and this complex then binds to the magnet, but what is the actual chemistry here, such as carbon or phosphate bonds of the DNA involved or how the makeup of the beads react to the DNA?)
4) are the 70% ethanol washing steps to remove any contaminants that are bound to the beads?
5) how does dna elute off in Tris while the beads are still bound to the magnet, again want to know the chemistry behind it?
6) how does XP performs faster cleanup versus Ampure, meaning what is the difference in the binding chemistry? Are the beads bigger in XP versus regular Ampure, or does bead size matter at all?