چكيده به لاتين
Adsorption and separation of biomolecules using modified magnetic nanoparticles (MNPs) is a inexpensive and fast method. In this study, adsorptions of two biomolecules of erythromycin (ERY) (pKa = 8.7-9) and bovine serum albumin (BSA) (pI = 4.7-5) on hydrophilic coated nanoparticles with single silica layer (TEOS) and hydrophobic coated nanoparticles with double layer including MPS polymer (with vinyl groups) on silica coating (TEOS@MPS) were investigated. Effective parameters such as pH, mass ratio of biomolecule to nanoparticles at different times on increasing the adsorption of biomolecules on both types of coated MNPs were investigated using a general factorial design method. The results showed that ERY as a hydrophobic biomolecule in phosphate buffer (pH = 6) in a mass ratio of 1:1 ERY to nanoparticles in 90 minutes has a maximum adsorption of 107 and 190 mg/g MNPs on hydrophobic and hydrophilic coating, respectively. In contrast, hydrophilic BSA biomolecule in 120 minutes has a maximum adsorption of 98 mg/g MNPs at pH = 4.5 on vinyl coating, whereas at pH=6, showed no adsorption due to electrostatic repulsion; whilst despite electrostatic repulsion, in 90 minutes, at pH = 6, 157 mg/g MNPs were adsorbed by silica hydrophilic coating. The results show that ERY biomolecule, despite its higher hydrophobic nature, due to possessing both hydrophilic and hydrophobic functional groups, even though exposes more of hydrophilic groups, can be adsorbed on both hydrophilic and hydrophobic coatings in a short time of 20 minutes, though the achieved adsorption efficiency on the hydrophilic coating was higher however. Despite having hydrophilic and hydrophobic functional groups, BSA as a hydrophilic biomolecule did not involve hydrophobic groups in binding to the vinyl hydrophobic coating, and as a result, at pH = 6, where there is electrostatic repulsion, no adsorption was observed, which in ERY purification, in the presence of BSA can be effective. ERY and BSA equilibrium adsorption data at 120 min were fitted to the pseudo-second-order and pseudo-first-order model, repectively. So the models indicating that the adsorption of ERY occurred chemically onto the hydrophobic and hydrophilic coated MNPs and the adsorption of BSA occurred physically onto these two coatings.
