TY - JFULL AU - Norzita Ngadi and John Abrahamson and Conan Fee and Ken Morison PY - 2009/2/ TI - Are PEG Molecules a Universal Protein Repellent? T2 - International Journal of Chemical and Molecular Engineering SP - 11 EP - 16 VL - 3 SN - 1307-6892 UR - https://publications.waset.org/pdf/7903 PU - World Academy of Science, Engineering and Technology NX - Open Science Index 25, 2009 N2 - Poly (ethylene glycol) (PEG) molecules attached to surfaces have shown high potential as a protein repellent due to their flexibility and highly water solubility. A quartz crystal microbalance recording frequency and dissipation changes (QCM-D) has been used to study the adsorption from aqueous solutions, of lysozyme and α-lactalbumin proteins (the last with and without calcium) onto modified stainless steel surfaces. Surfaces were coated with poly(ethylene imine) (PEI) and silicate before grafting on PEG molecules. Protein adsorption was also performed on the bare stainless steel surface as a control. All adsorptions were conducted at 23°C and pH 7.2. The results showed that the presence of PEG molecules significantly reduced the adsorption of lysozyme and α- lactalbumin (with calcium) onto the stainless steel surface. By contrast, and unexpected, PEG molecules enhanced the adsorption of α-lactalbumin (without calcium). It is suggested that the PEG -α- lactalbumin hydrophobic interaction plays a dominant role which leads to protein aggregation at the surface for this latter observation. The findings also lead to the general conclusion that PEG molecules are not a universal protein repellent. PEG-on-PEI surfaces were better at inhibiting the adsorption of lysozyme and α-lactalbumin (with calcium) than with PEG-on-silicate surfaces. ER -