Title

DNA isolation using avidin-coated magnetic nanoclusters

Document Type

Article

Date of Original Version

4-10-1997

Abstract

Using simple colloidal processing techniques, we have produced stable suspensions of avidin-coated magnetic nanoclusters and demonstrated their efficacy in magnetic triple-helix affinity capture. A mixture of target and non-target DNA is incubated with a biotinylated oligonucleotide containing a triple-helix sequence that binds to the homopurine-homopyrimidine sequence in the target under mild acidic conditions. The target DNA is then 'magnetized' by contact with avidin-coated magnetic nanoclusters through the avidin- biotin linkage. Exposure to a magnetic field gradient selectively moves the target and immobilizes the particles in the region of the highest magnetic field, leaving the non-target DNA dispersed in the remaining solution. This solution is withdrawn in the presence of the magnetic field gradient. The immobilized particle-target clusters are then exposed to mild basic conditions. The triple helix dissociates, releasing the magnetized oligonucleotides without affecting the double-stranded DNA. A second application of the magnetic field gradient is used to separate the magnetic particles from the DNA. The double-stranded target DNA is then available directly for further processing.

Publication Title

Colloids and Surfaces B: Biointerfaces

Volume

8

Issue

4-5

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