Determination of Peptide-Surface Adsorption Free Energy for Material Surfaces Not Conducive to SPR or QCM using AFM

作者：Thyparambil Aby A; Wei Yang; Latour Robert A^*

来源：Langmuir, 2012, 28(13): 5687-5694.

DOI：10.1021/la300315r

The interactions between peptides and proteins with material surfaces are of primary importance in many areas of biotechnology. While surface plasmon resonance spectroscopy (SPR) and quartz crystal microbalance (QCM) methods have proven to be very useful in measuring fundamental properties characterizing adsorption behavior, such as the free energy of adsorption for peptide-surface interactions, these methods are largely restricted to use for materials that can readily form nanoscale-thick films over the respective sensor surfaces. Many materials including most polymers, ceramics, and inorganic glasses, however, are not readily suitable for use with SPR or QCM methods. To overcome these limitations, we recently showed that desorption forces (F-des) obtained using a standardized AFM method linearly correlate to standard-state adsorption free energy values (Delta G degrees(ads)) measured from SPR in phosphate buffered saline (PBS: phosphate buffered 140 mM NaCl, pH 7.4). This approach thus provides a means to determine Delta G degrees(ads) for peptide adsorption using AFM that can be applied to any flat material surface. In this present study, we investigated the F-des-Delta G degrees(ads) correlation between AFM and SPR data in PBS for a much broader range of systems including eight different types of peptides on a set of eight different alkanethiol self-assembled monolayer (SAM) surfaces. The resulting correlation was then used to estimate Delta G degrees(ads) from F-des determined by AFM for selected bulk polymer and glass/ceramic materials such as poly(methyl methacrylate) (PMMA), high-density polyethylene (HDPE), fused silica glass, and a quartz (100) surface. The results of these studies support our previous findings regarding the strong correlation between F-des measured by AFM and Delta G degrees(ads) determined by SPR, and provides a means to estimate Delta G degrees(ads) for peptide adsorption on macroscopically thick samples of materials that are not conducive for use with SPR or QCM.

• 出版日期2012-4-3