cell binding assay with nanoparticles? - (Mar/21/2013 )

hey folks - I've recently picked up a new project, with very new techniques, and I've run into a minor stumbling block.

our collaborators have sent me some nanoparticle they have made. they have conjugated it to an antibody we use for targeting certain cell types. I need to assay for functionality to be certain our antibody targeting is not hindered by addition of the nanoparticle.

our typical plate-based cell binding assays involve adding our antibody to cells (human lymphoma and/or leukemia cells), going through a few wash steps, and assaying for remaining antibody (unbound Ab will be removed with supernatant when cells are pelleted).

well, the NP is very dense and can't be washed away. any spin that will pellet out cells will also pellet out Ab.

the NP is also magnetic, but I don't know a way to clearly pull the cells-Ab-NP complex out and quantify binding.

does anyone have any suggestions?

Could you pull the beads out and quantify the amount of Ab by HPLC?

it's possible we will have to use some sort of magnetic separation and do a backwards assay for the Ab that's left in solution. we're brainstorming...it's also possible a column can be designed to pull cells out of solution based on another surface receptor. it's an interesting puzzle.