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Microbial colonization and biofilm formation on implanted devices represent an important complication in orthopaedic and dental surgery and may result in implant failure. Controlled release of antibacterial agents directly at the implant site may represent an effective approach to treat these chronic complications. Resistance to conventional antibiotics by pathogenic bacteria has emerged in recent years as a major problem of public health. In order to overcome this problem, non-conventional antimicrobial agents have been under investigation. In this study, polyacrylate-based hydrogel thin coatings have been electrosynthesised on titanium substrates starting from poly(ethylene glycol diacrylate)-co-acrylic acid. Silver nanoparticles (AgNPs) with a narrow size distribution have been synthesized using a "green" procedure and immobilized on Ti implant surfaces exploiting hydrogel coatings' swelling capabilities. The coatings have been characterized by XPS and SEM/EDX, while their silver release performances have been monitored by ICP-MS. The antibacterial activity of these AgNP-modified hydrogel coatings was tested evaluating in vitro inhibition growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, among the most common pathogens in orthopaedic infections. Moreover, a preliminary investigation of the biocompatibility of silver-loaded coatings versus MG63 human osteoblast-like cells has been performed. An important point of strength of this paper, in fact, is the concern about the effect of silver species on the surrounding cell system in implanted medical devices. Silver ion release has been properly tuned in order to assure antibacterial activity while preserving osteoblasts' response at the implant interface.

The protection of metal orthopedic implants against corrosion is a crucial medical problem. It was found that electrochemical polymerization of thin, passive poly(acrylic acid) (PAA) films on titanium and TiAlV substrates provides good anti-corrosion properties. In this work, an investigation of anti-corrosion features was carried out to clarify the hypothesis of the presence of an electrostatic contribution to the performance of a PAA coating. Ion release tests were performed at three different pHs; the pH dependence of the polymer swelling was examined by quartz crystal microbalance with dissipation monitoring, to establish the role of this phenomenon on the polymer barrier properties. The potential application of these PAA thin films as biocompatible protective coatings for metal implants and compatibility towards MG-63 human osteoblast-like cells was assessed.

The formulation and characterization of dopamine (DA)-loaded chitosan nanoparticles (CSNPs) are described as preliminary steps for the development of potential DA carrier systems intended for Parkinson's disease treatment. For this purpose, CSNPs were firstly produced and, afterwards, they were incubated in a DA aqueous solution to promote neurotransmitter loading. The characterization of the resulting nanoparticles started with Fourier transform infrared spectroscopy analysis to ascertain the presence of DA in the nanocarrier, whereas X-ray photoelectron spectroscopy analysis provided evidence of the localization of DA on the nanoparticle surface. A quartz crystal microbalance with dissipation monitoring (QCM-D) was then exploited to investigate both swelling of CSNPs and interaction of DA with CSNPs. In particular, the QCM-D revealed that this interaction is fast and so this allows a stable nanostructured system to be obtained.