Nonspecific-adsorption behavior of polyethylenglycol and bovine serum albumin studied by 55-MHz wireless–electrodeless quartz crystal microbalance

• Published in: Biosensors & bioelectronics 2009-06, Vol.24 (10), p.3148-3152
• Main Authors: Ogi, Hirotsugu, Fukunishi, Yuji, Nagai, Hironao, Okamoto, Ken, Hirao, Masahiko, Nishiyama, Masayoshi
• Format: Article
• Language: English
• Subjects: Adsorption; Affinity; Animals; Binding Sites; Biological and medical sciences; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensing Techniques - statistics & numerical data; Biotechnology; Cattle; Crystallization; Electrochemical Techniques; Electrodeless; Fundamental and applied biological sciences. Psychology; Gold; Humans; Immunoglobulin G; Kinetics; Nonspecific adsorption; Polyethylene Glycols; QCM; Quartz; Sensitivity and Specificity; Serum Albumin, Bovine; Silicon Dioxide; Staphylococcal Protein A; Staphylococcus; Surface Properties
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2009.03.035

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 α -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 = 4.2 × 1 0 4 M −1) and the Au surface ( K A = 6.6 × 1 0 4 M −1), but BSA shows higher affinity for the SiO 2 surface ( K A = 1.4 × 1 0 6 M −1). Both PEG and BSA show low affinities for hIgG ( K A ∼ 1.5 × 1 0 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.