Development of a molecularly imprinted polymer for the recovery of lactoferrin

• Molecular imprinting was successfully used to separate a valuable protein from a complex mixture.
• Accessible Surface Area proved to be a valuable tool for the selection of proper functional monomer.
• Molecular imprinting could be us for the purification of valuable whey proteins.

Lactoferrin (LF) was recovered by molecular imprinting using either vinylpirydin alone (MIP1) or mixed with methacrylic acid (MIP2) as functional monomers. In order to create the specific cavity, pure LF was used as template. Controls were prepared for every MIP. The polymers obtained were tested against a protein mixture containing LF, and the recovery efficiency was calculated determining the diminution of LF from the supernatant by titration of the iron of the LF, as well as native PAGE to determine the protein composition of the supernatants. The only polymer which was able to specifically bind LF was MIP1 (vinylpirydin alone). Measuring the proportions of the different proteins in the mixture, it was demonstrated that before the separation with MIP1, LF represented 81.9% of the total protein content of the mixture, and diminished to 70.5% after the exposure to MIP1, suggesting that LF was specifically sorbed by this polymer. The retention efficiency of the polymer showed that MIP1 retained 34.5% of the total LF content, while its control did not retain any, demonstrating that the retention of the protein is not due to unspecific adsorption in the polymer, but rather to a selective retention in the cavity formed by the template.