We report the development of thermoresponsive 4-mercaptoethylpyridine (MEP)-based chromatographic microsphere based resins for antibody separation that show switchable release abilities by adsorbing immunoglobulins at 40 °C and releasing the proteins at 5°C. The thermoswitchable release properties were introduced to the porous resins by the grafting of linear poly (N-isopropylacrylamide) (PNIPAM) chains synthesized via reversible addition−fragmentation chain transfer (RAFT) polymerization, which were modified to possess MEP end functionalities.

Adsorption of γ-globulins as a model antibody on the shortest PNIPAM-MEP (3 kDa) grafted microparticles display binding capacities of up to 20 g L − 1 at 40 °C and a significant decrease in binding capacity to less than 2.5 g L − 1 at 5 °C.

By switching the temperature to 5 °C, the release of bound γ-globulins is shown to be as high as 90%. The effects of polymer chainlength on the binding capacity are studied in detail and found to be critical as they influence the density of MEP functionalities on the particle surfaces.