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Functionalization of medical devices with biomolecules is a key strategy to control implant outcomes, for instance, polyphenols can produce fast osseointegration and reduce both the infection risk and inflammatory response. This paper is designed to evaluate the role of calcium ions and surface features in surface functionalization with a red pomace extract. An in-depth investigation of the binding mechanism between surfaces and polyphenols was also performed. A smooth Ti6Al4V alloy was used as a control substrate and compared with a bioactive and nanotextured chemical-treated Ti6Al4V alloy. Solutions with and without the addition of calcium ions were used for functionalization. The results showed that polyphenols were adsorbed in all cases, but in a larger amount in the presence of calcium ions. The functionalized surfaces were hydrophilic (contact angles in the range of 45–15°) and had isoelectric points at pH 2.8–3.1. The acidic hydroxyl groups on the chemically treated titanium alloy favored the chemisorption of complex compounds of flavonoids and condensed tannins with calcium ions, through a bridging mechanism, and made desorption sensitive to pH. On the smooth surface, the absence of reactive functional groups led to a lower amount of adsorbed molecules and a physisorption mechanism. Selective physisorption of phenolic acids was supposed to be predominant on the smooth surface in the presence of calcium ions in the solution.

Surface chemistry, charge, wettability, and roughness affect the adsorbed protein layer, influencing biocompatibility and functionality of implants. Material engineering seeks innovative, sensitive, and reliable characterization techniques for study the adsorbed proteins. These techniques must be suitable to be directly used on the surfaces of clinical interest. In this paper, the characterization of surfaces with topography and chemistry developed for osseointegration is performed by innovative surface analysis techniques to investigate the properties of adsorbed bovine serum albumin. Ti6Al4V alloy chemically treated with an oxidative process to obtain peculiar surface features (roughness and surface hydroxylation) was tested and compared with mirror-polished titanium. Albumin forms a continuous layer on both Ti surfaces when adsorbed from near physiological concentrations, as proved by Kelvin force probe microscopy. It was observed that the hydroxylation degree plays a pivotal role in determining the conformation of proteins after adsorption, where it strongly drives protein unfolding, as confirmed by Surface Enhanced Raman scattering, and in influencing the mechanism and chemical stability of protein-surface interactions, which was highlighted by zeta potential titration curves.

Nano- and micro-structuring of implantable materials constitute a promising approach to introduce mechanical contact guidance effect, drive cells colonization, as well as to prevent bacteria adhesion and biofilm aggregation, through antifouling topography. Accordingly, this paper aims to extend the application of e-beam surface texturing and nano-structuring to the beta titanium alloys, which are of great interest for biomedical implants because of the low Young modulus and the reduction of the stress shielding effect. The paper shows that surface texturing on the micro-scale (micro-grooves) is functional to a contact guidance effect on gingival fibroblasts. Moreover, nano-structuring, derived from the e-beam surface treatment, is effective to prevent microfouling. In fact, human fibroblasts were cultivated directly onto grooved specimens showing to sense the surface micro-structure thus spreading following the grooves’ orientation. Moreover, Staphylococcus aureus colonies adhesion was prevented by the nano-topographies in comparison to the mirror-polished control, thus demonstrating promising antifouling properties. Furthermore, the research goes into detail to understand the mechanism of microfouling prevention due to nano-topography and microstructure.

Nowadays, there is a large amount of research aimed at improving the multifunctional behavior of the biomaterials for bone contact, including the concomitant ability to induce apatite formation (bioactivity), fast and effective osteoblasts colonization, and antibacterial activity. The aim of this study is to develop antibacterial and bioactive surfaces (Ti6Al4V alloy and a silica-based bioactive glass) by chemical doping with strontium and/or silver ions. The surfaces were characterized by Scanning Electron Microscopy equipped with Energy Dispersive X ray Spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), and Transmission Electron Microscopy (TEM). To better focus on the cells−bacteria competition for the implant surface, in addition to the standard assays for the evaluation of the bacteria adhesion (ISO22196) and for single-cell cultures or biofilm formation, an innovative set of co-cultures of cells and bacteria is here proposed to simulate a competitive surface colonization. The results suggest that all the bioactive tested materials were cytocompatible toward the bone progenitor cells representative for the self-healing process, and that the doped ones were effective in reducing the surface colonization from a pathogenic drug-resistant strain of Staphylococcus aureus. The co-cultures experiments demonstrated that the doped surfaces were able to protect the adhered osteoblasts from the bacteria colonization as well as prevent the infection prior to the surface colonization by the osteoblasts.

Nowadays, bioactive glasses (BGs) are mainly used to improve and support the healing process of osseous defects deriving from traumatic events, tumor removal, congenital pathologies, implant revisions, or infections. In the past, several approaches have been proposed in the replacement of extensive bone defects, each one with its own advantages and drawbacks. As a result, the need for synthetic bone grafts is still a remarkable clinical challenge since more than 1 million bone-graft surgical operations are annually performed worldwide. Moreover, recent studies show the effectiveness of BGs in the regeneration of soft tissues, too. Often, surgical criteria do not match the engineering ones and, thus, a compromise is required for getting closer to an ideal outcome in terms of good regeneration, mechanical support, and biocompatibility in contact with living tissues. The aim of the present review is providing a general overview of BGs, with particular reference to their use in clinics over the last decades and the latest synthesis/processing methods. Recent advances in the use of BGs in tissue engineering are outlined, where the use of porous scaffolds is gaining growing importance thanks to the new possibilities given by technological progress extended to both manufacturing processes and functionalization techniques.