I'm having a glass surfaces and I want to adsorb proteins onto them. I have no problem, when I first adsorb fibronectin (human) onto some areas and afterwards any other protein. The second protein will only adsorb onto the remaining "free" areas.
But as soon as I apply fibronectin in the second place, it just adsorbs everywhere. And I want to avoid this.
More detailed Protocol
(direct microcontact printing):
- Incubate a pdms-stamp with Protein-Solution #1 for some time and concentration
- Dry pdms stamp and press onto coverslip for some time
- Remove stamp and put a drop of Protein-Solution #2 for some time and concentration onto the coverslip
I varried already concentrations and times without noticeable success. I also tried adding some BSA to Fibronectin - also without success. All solutions are within PBS.
Further steps I anticipate:
- Varying pH around the protein's isolectric point (Fibronectin: around 5.2)
- Adding some detergens to fn-solution (e.g. Tween)
- Variation of salt-content in fn-protein-buffer
I'm wondering what the exact reason for the stickiness of Fibronectin is and which parameter is the best to vary? Did I miss something? Does Fibronectin stick to the other proteins or rather to "free areas" of the surface?
Please note: surface modification techniques (e.g. using epoxys) are no option.
I'm not sure, whether this topic perhaps suits the chemistry-community better. Feel free to move.