Proteins have amid groups in their structure and negative charge so you must modify surface of your adsorption by ligand with positive charge such as quaternary amin groups.

Thanks. what you suggest about peptides and antibodies?

You need to specify the type of proteins you are planning to use and also on type of nanoparticles [especially in terms of net charge, size etc.] you wish to adsorb on the surface of these proteins.

P. Pardha-Saradhi BSA, OVA, B-casein by using silica coated iron nanoparticles. Basically I want to enhance adsorption capacity.

P. Pardha-Saradhi Mohammad Reza Toosi can you suggest me some idea about this?

Modify silica surface by APTS and then bond it with CTAB.

Mohammad Reza Toosi this work is already reported. Need modification with unique ligand

Dear Shumaila,

Can you please let me know your primary goal? Are you planning to use BSA/Casein with immobilized silica coated iron oxide nanoparticles for water purification or dye decolorization/degradation?

P. Pardha-Saradhi my goal is to adsorb/enrich protein from a given mixture. I have to use silica coated magnetic nanoparticles for the purpose of separation. As this work is already reported so I am looking for a different ligands which I should use to modify silica nanoparticles. In odor to increase adsorption capacity as well as selectivity

Change surface modifier, ligand, surfactant....

Dear Shumaila,

It depends on type of protein and amino acid composition of proteins. It may be more easy to capture the ones rich in cysteine, histidine etc. Please refer to attached Handbook for Protein purification/separation. Depending on type/composition of protein you may accordingly plan - so that you can prepare affinity chromatographic column with modified silica coated magnetic nanoparticles.

If you have to simply separate protein from a mixture, you may simply go for ammonium sulfate precipitation method instead of trying a complicated method. However, if you have to separate a definite protein from mixture of proteins or crude protein extract, you can go for affinity chromatography [wherein you can use silica coated magnetic nanoparticles with specific ligand as beads]. Ligand can even be a specific monoclonal antibody, Nickel etc.