## 1 Introduction  
In the orthopedic and orthodontic fields, titanium alloys are commonly employed for their exceptional combination of biocompatibility, chemical stability, mechanical strength, fatigue resistance and high corrosion resistance [1; 2]. However, these materials present some disadvantages that need to be addressed. One of these regards the bacterial-associated diseases/infections during surgery, which could not only lead to implant failure, but also have deleterious side effects. In order to reduce the risk of infection, many preventative strategies have been proposed with the aim of improving the antibacterial ability of the material before surgery [3; 4]. Most of the solutions suggested for obtaining an antibacterial surface without losing its bioactivity were based on the use of coatings. One processing technique developed and used nowadays to produce coatings is electrospinningning. The type of polymer employed is an important factor responsible for the features of the nanofibers [5]. One of the most used materials for the development of electrospinningning nanofibers is chitosan (CS), a biopolymer obtained by deacetylation of chitin, which consists of repeating units of \(N\)-acetyl-D-glucosamine and \(N\)-glucosamine linked by glycosidic bonds [6]. It possesses various technological properties like biodegradability and biocompatibility, as well as antiviral, insecticidal and antimicrobial activity [7]. CS nanofibers, in particular, were found to be effective in inhibiting the growth of several bacterial strains [8; 9; 10; 11]. Furthermore, due to its structural similarity with glycosaminoglycan (which is one of the main bone and cartilage constituents), it plays important roles in the attachment, differentiation, and morphogenesis of osteoblast cells, providing the cell signals necessary for bone formation [12; 13; 14]. CS is used in the production of different hybrid scaffolds upon mixing with a second polymer. An example is represented by polyethylene oxide (PEO), a synthetic polymer as a second component in order to improve spinning stability and increase the chain entanglement of chitosan, while the electrical conductivity of the spinning solution decreases [15; 16; 17; 18]. This mixture facilitates fiber formations.  
Through electrospinningning technique, it is possible to incorporate a variety of bioactive inorganic materials into the polymeric fibers. Among these there are bioactive glasses (BGs), which are commonly used as promising scaffold materials for bone and soft tissue regeneration [19]. For orthopedic applications, different composite nanofiber scaffolds have been developed using CS and other polymers and incorporating bioactive glasses [20; 21; 22; 23; 24]. However, in literature no comparison of these composite coatings with uncoated titanium alloys has been yet provided in order to evaluate effectively the antibacterial effect and the simultaneous osteeconductive activity. In this study, the major objective was to produce composite nanofibers deposited on titanium alloy disks using CS blended with polyethylene oxide (PEO) and BG incorporated into the solution in order to improve the bioactivity and the antimicrobial properties of the bulk. The bacteriostatic behavior and the bone tissue formation were monitored in comparison with Ti-alloy and CS/PEO nanofibers without BG, investigating the properties of the different substrates and subsequently performing different biological tests.