Biotechnological Approaches to Purifying High Value Products (i.e. antibodies)

Must write about the purification what it is and why it important and the methods and some examples. The examples should be Insulin, Antibodies, Protein A, and DARPins. Should write about the purification methods and the therapeutic use of each example. Add some marketing analysis information and any other related issues about them.
Need to focus more in Insulin than other examples.

Essay should be no more than 2000 words in length.
No limit for references but no less than 10.