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.

Introduction: According to the 2016 Italian National Institute of Statistics (Istat) data in Italy, about 6.7% of all newborns are born prematurely. Due to the lack of data on current complementary feeding in preterm infants in Italy, the aim of the survey was to evaluate individual attitudes of primary care paediatricians, concerning the introduction of complementary foods in preterm infants. Methods: An internet-based survey was conducted among primary care paediatricians, working in Italy, regarding (1) timing of the introduction of complementary foods to preterm newborns; (2) type of complementary foods introduced; (3) vitamin D and iron supplementations. Results: A total of 347 primary care Italian paediatricians answered the questionnaire; 44% of responders based the timing of the introduction of solid food exclusively on an infant’s age, 18% on an infant’s neurodevelopmental status and 4% on the body weight; the remaining 34% based the timing on two or more of these aspects. The type of complementary foods did not comply with an evidence-based sequence; 98% of participants promoted vitamin D supplementation and 89% promoted iron supplementation with great diversity in timing and doses. Conclusions: Due to limited evidence, there is a great heterogeneity in the attitudes of primary care paediatricians concerning the introduction of complementary foods to preterm newborns. Further research is needed to provide evidence-based guidelines regarding weaning preterm newborns.

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