Paramagnetic particles

Blaine Stine stine at
Wed Jun 24 10:52:46 EST 1992

In article <3418 at>.
> pnh at (Paul N Hengen) writes:
>  Here's my question:
>  We recently purchased some streptavidin paramagnetic particles
>  -nucleic acid qualified (cat. no. Z524/1,2) from Promega and
>  would like to know some more information concerning these beads.
>  1. What are the size of the particles?

Well they vary in size. I've imaged them in the TEM and with
my Atomic Force Microscope and they seem to average around
500nm but I've seen them as big as 1.5um and as small as
100nm. BTW these "MagneSphere" particles are in no way 
round! They're more like "MagneBlobs". The Dynal M-280
magnetic particles are very round and have a mean dia. of 
2.8um +/- 0.2um  if that's what you need.

>  2. What is the concentration of particles in the supplied buffer?

1 mg/ml

>  3. What is the buffer that the particles are shipped in?

PBS and it may have some BSA and/or Azide for the Streptavidin

>  4. What is the binding capacity of the beads for biotinylated
>  	oligonucleotides?

1.08 nanomoles biotinylated oligo d(T) per mg particles
1.1% Non-specific binding of radiolabeled oligo d(T) (no biotin)
is captured after incubation with 2ml particles for 10min at RT

>  Paul N. Hengen

All of this info can be found on the Certificate of Analysis
provided with the MagneBlobs. The info given here is for
lot 08540. They get their particles from Advanced Magnetics
and I think they coat them with Streptavidin themselves.
Also, check out Edmund Scientific for a good source for 
rare earth magnets. If you need more help drop me a line..

Blaine Stine
UCSD Biology 
Scanning Tunneling / Atomic Force Microscopy
stine at

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