Department of Inorganic and Analytical Chemistry School of Chemistry and Biochemistry

Tuesday, December 13, 2016, 15:30–16:30 Room 174, Sciences II

Katarzyna Kubiak

University of Strasbourg, Strasbourg, France Noble metal particles play an important role due to their wide range of practical applications in many different areas of nanoscience and technology. Especially significant are silver nanoparticle monolayers and films deposited on solid surfaces, which offer a wide spectrum of applications as e.g. antibacterial coatings, catalytic materials, antireflection coatings or filters. Fibrinogen is a protein which has a fundamental role in many important processes e.g. blood clotting cascade, platelet adhesion, inflammatory response and thrombosis. Because of wide application capabilities like bio sensing, immunological assays and disease diagnostic, investigation of fibrinogen deposition kinetic on various substrates plays an important role in nanoscience.

The quartz crystal microbalance (QCM) offers an opportunity to investigate in situ kinetics of protein and silver nanoparticles deposition by controlling a mass of particles adsorbed on a surface of a sensor. In the first part of this work silver particle monolayers at polyelectrolyte modified surfaces were investigated. The deposition kinetics of silver nanoparticles at SiO2/PAH substrate were studied under in situ conditions by using the QCM method and the ex situ AFM and SEM imaging. Measurements were done for various bulk suspension concentrations, flow rates and ionic strengths. It was shown that particle deposition for the low coverage regime is governed by the bulk mass transfer step that results in a linear increase of the coverage with the time. A comparison of QCM and SEM results showed that the hydration of the silver monolayers was negligible. This allowed one to derive a universal kinetic equation that describes the mass transfer rates in the QCM cell as a function of the bulk concentration, flow rate and diffusion coefficient.

The fibrinogen adsorption kinetics at SiO2 surface were determined for various conditions such as bulk suspension concentration, flow rate and pH, using QCM method. These experimental data were compared with the theoretical dry coverage data derived from the solution of the mass transfer equation. In this way, the hydration functions and water factors of fibrinogen monolayers were quantitatively evaluated for various pHs. Measurements which were performed, lead us to obtain the maximum coverage of proteins which were adsorbed on a QCM sensor.

Formation of Silver Nanoparticle Monolayers as a Reference System useful for the Interpretation of Protein

Adsorption Kinetic Runs