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Issue 13, 2017
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Controlling adsorption and passivation properties of bovine serum albumin on silica surfaces by ionic strength modulation and cross-linking

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Abstract

Understanding the physicochemical factors that influence protein adsorption onto solid supports holds wide relevance for fundamental insights into protein structure and function as well as for applications such as surface passivation. Ionic strength is a key parameter that influences protein adsorption, although how its modulation might be utilized to prepare well-coated protein adlayers remains to be explored. Herein, we investigated how ionic strength can be utilized to control the adsorption and passivation properties of bovine serum albumin (BSA) on silica surfaces. As protein stability in solution can influence adsorption kinetics, the size distribution and secondary structure of proteins in solution were first characterized by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and circular dichroism (CD) spectroscopy. A non-monotonic correlation between ionic strength and protein aggregation was observed and attributed to colloidal agglomeration, while the primarily α-helical character of the protein in solution was maintained in all cases. Quartz crystal microbalance-dissipation (QCM-D) experiments were then conducted in order to track protein adsorption onto silica surfaces as a function of ionic strength, and the measurement responses indicated that total protein uptake at saturation coverage is lower with increasing ionic strength. In turn, the QCM-D data and the corresponding Voigt–Voinova model analysis support that the surface area per bound protein molecule is greater with increasing ionic strength. While higher protein uptake under lower ionic strengths by itself did not result in greater surface passivation under subsequent physiologically relevant conditions, the treatment of adsorbed protein layers with a gluteraldehyde cross-linking agent stabilized the bound protein in this case and significantly improved surface passivation. Collectively, our findings demonstrate that ionic strength modulation influences BSA adsorption uptake on account of protein spreading and can be utilized in conjunction with covalent cross-linking strategies to prepare well-coated protein adlayers for improved surface passivation.

Graphical abstract: Controlling adsorption and passivation properties of bovine serum albumin on silica surfaces by ionic strength modulation and cross-linking

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Publication details

The article was received on 28 Feb 2017, accepted on 03 Mar 2017 and first published on 06 Mar 2017


Article type: Paper
DOI: 10.1039/C7CP01310H
Citation: Phys. Chem. Chem. Phys., 2017,19, 8854-8865
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    Controlling adsorption and passivation properties of bovine serum albumin on silica surfaces by ionic strength modulation and cross-linking

    J. H. Park, T. N. Sut, J. A. Jackman, A. R. Ferhan, B. K. Yoon and N. Cho, Phys. Chem. Chem. Phys., 2017, 19, 8854
    DOI: 10.1039/C7CP01310H

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