Glass-ceramics: Fundamental aspects regarding the interaction with proteins

Abstract

Understanding protein adsorption to solid surfaces represents a topic of general interest, this phenomenon being crucial for disciplines such as biochemical engineering, biotechnology, biomedicine, biology, and environment science. For instance, in the field of biomedicine, it is of great importance to assess the adsorption of blood proteins to implants. This complex process is driven by different protein–surface or protein–protein forces and is strongly influenced by parameters like pH, temperature, ionic strength, protein type, and by the chemical and physical characteristic of the surface. Despite an increased understanding of many peculiarities of protein adsorption achieved in recent years, there still are unanswered questions or contradictory opinions related to this research topic. The present chapter summarizes some basic characteristics of the protein adsorption process, with focus on glass-ceramic type materials. The examples of protein adsorption studies described in the present material aim to enlighten aspects related to conformational changes or structural rearrangements of the protein domains upon adsorption, influence of surface functionalization on proteins adsorption and to elucidate details concerning protein dynamics and the amount of the protein attached. Three types of glass-ceramic materials were considered as concrete examples: bioactive glasses designed for tissue engineering, aluminosilicate glass-ceramics intended for both hyperthermia and radiotherapy applications, and silica matrices aiming to be used for therapeutic proteins delivery. Among the many methods used to investigate adsorption of proteins on solid surfaces, three spectroscopic techniques are highlighted: the method of site-directed spin labeling combined with electron paramagnetic resonance, Fourier transform infrared, and X-ray photoelectron spectroscopy.