HABA and avidin-coated beads

[Sanjay Vijendran]

Hi All,

 I'm hoping to demonstrate avidin-biotin binding by first adding HABA
reagent to a solution of avidin-coated 10 micron silica beads in a
microchannel, observing a change in the colour of the beads  from
colourless to red, then adding biotin to show the beads go colourless
again.

 My question is can I expect to see individual 10 micron beads turn
red when reacted with the HABA under the microscope? I was wondering
whether the amount of protein on the bead surfaces may be too little
to expect to see a change in the colour of the bound dye.

 Anyone have any comments on this?

Thanks.

Regards,
Sanjay Vijendran