title: Thermo-responsive adsorbent for size-selective protein adsorption.
abstract: A thermo-responsive random copolymer, POEGMA (poly(oligoethylene glycol) methacrylate) grafted on cationized agarose adsorbent was used for size selective protein adsorption. The effects of OEGMA300 ((oligoethylene glycol) methyl ether methacrylate, Mn=300g/mol) content and temperature on the adsorption of bovine serum albumin (BSA) were evaluated. Increasing the content of OEGMA300 resulted a reduction in BSA adsorption due to the enhanced shielding effect of OEGMA300 chains. Grafting of POEGMA chains onto cationized agarose adsorbent reduced the BSA adsorption by more than 95% at 26.5°C, which is below the LCST (lower critical solution temperature) of POEGMA. The BSA adsorption capacities for adsorbents grafted with 10 and 20mol% of OEGMA300 decreased by 48% and 46% respectively at 38°C, a temperature higher than their LCSTs. The temperature-dependent adsorption of BSA on the adsorbents was attributed to changes in the polymer conformation. The thermal transition of grafted POEGMA conformation exposed the ligand when the temperature was increased. Myoglobin (Myo), which was smaller than BSA, its adsorption behavior was less dependent on the polymer conformation. The adsorption of myoglobin onto the adsorbent with and without POEGMA showed similar percentage of reduction whereas the adsorption of BSA onto the adsorbent with POEGMA decreased by 7.6 times compared to the one without POEGMA. The packed bed of POEGMA grafted adsorbent was used for flow through separation of a protein mixture consisted of virus-like particle, Hepatitis B virus-like particle (HBVLP), BSA and insulin aspart. The recovery of HBVLP in 20mol% of OEGMA300 grafted adsorbent was increased by 19% compared to ungrafted adsorbent. The flow through of BSA can be reduced by increasing the operating temperature above LCST of 20mol% of OEGMA300 while the smaller protein, insulin aspart, remained adsorbed onto the cationized surface. Hence, this thermo-responsive adsorbent has a potential for size-selective separation of protein especially for the recovery of large biomolecule.
authors.affiliation: Chemical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, Malaysia.
authors.forename: Micky Fu Xiang
authors.initials: MF
authors.lastname: Lee
authors.affiliation: Chemical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, Malaysia; Multidisciplinary Platform of Advanced Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, Malaysia.
authors.forename: Eng Seng
authors.initials: ES
authors.lastname: Chan
authors.affiliation: Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: Kam Chiu
authors.initials: KC
authors.lastname: Tam
authors.affiliation: Chemical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, Malaysia; Multidisciplinary Platform of Advanced Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, Malaysia. Electronic address: tey.beng.ti@monash.edu.
authors.forename: Beng Ti
authors.initials: BT
authors.lastname: Tey
mesh_terms: D000327:Adsorption; D006515:Hepatitis B virus / Q000737:chemistry; D061267:Insulin Aspart / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry*; D009211:Myoglobin / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012996:Solutions; D013696:Temperature; D014771:Virion / Q000737:chemistry
chemical_list: D008689:Methacrylates; D009211:Myoglobin; D011506:Proteins; D012996:Solutions; C524499:polyethylene glycol methacrylate; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D061267:Insulin Aspart
keywords: Ion exchange chromatography; Lower critical solution temperature (LCST); Phase transition; Poly(oligoethylene glycol) methacrylate (POEGMA); Temperature-dependent; Thermo-responsive