Nonspecific-adsorption behavior of polyethylenglycol and bovine serum albumin studied by 55-MHz wireless-electrodeless quartz crystal microbalance.
The nonspecific binding ability of polyethylenglycol (PEG) and bovine serum albumin (BSA) on modified and unmodified surfaces is quantitatively studied by a wireless-electrodeless quartz crystal microbalance (WE-QCM). PEG and BSA are important blocking materials in biosensors, but their affinities for proteins and uncoated substrates have not been known quantitatively. The WE-QCM allows quantitative analysis of the adsorption behavior of proteins on the electrodeless surfaces. Affinities of PEG, BSA, human immunoglobulin G (hIgG), and Staphylococcus protein A (SPA) for alpha-SiO(2)(quartz), Au thin film, PEG, and BSA are systematically studied by the homebuilt flow-injection system. PEG shows low affinities for the SiO(2) surface (K(A)=4.2x10(4) M(-1)) and the Au surface (K(A)=6.6x10(4) M(-1)), but BSA shows higher affinity for the SiO(2) surface (K(A)=1.4x10(6) M(-1)). Both PEG and BSA show low affinities for hIgG (K(A) approximately 1.5x10(5) M(-1)). However, the number of binding sites of PEG to hIgG is significantly larger than that of BSA, indicating that blocking for hIgG is favorably achieved by BSA, rather than PEG.
Ogi
Hirotsugu
H
Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan. ogi@me.es.osaka-u.ac.jp
Fukunishi
Yuji
Y
Nagai
Hironao
H
Okamoto
Ken
K
Hirao
Masahiko
M
Nishiyama
Masayoshi
M
D000327:Adsorption; D000818:Animals; D001665:Binding Sites; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D002417:Cattle; D003460:Crystallization; D055664:Electrochemical Techniques; D006046:Gold; D006801:Humans; D007074:Immunoglobulin G; D007700:Kinetics; D011092:Polyethylene Glycols; D011791:Quartz; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine; D012822:Silicon Dioxide; D013205:Staphylococcal Protein A; D013499:Surface Properties
D007074:Immunoglobulin G; D013205:Staphylococcal Protein A; D011791:Quartz; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D006046:Gold; D012822:Silicon Dioxide