The adhesive capabilities of marine mussel proteins are well-known, exhibiting the ability to stick to different underwater substrates, either inorganic or organic. These unique adhesive properties are due to the high levels of amino acid, 3,4-dihydroxyphenyl-L-alanine (DOPA), which presents the reactive catechol group. Herein, novel antibacterial free-standing (FS) films were developed with natural polymers, namely chitosan (CHT) and hyaluronic acid (HA), being the catechol-functionalized hyaluronic acid (HA-DN) also included to provide wet adhesive properties. In order to obtain composite films, silver doped bioglass nanoparticles (Ag-BGs) were incorporated to promote bactericidal and bioactive properties, being tested four distinct formulations of FS films. Their surface morphology and topography, wettability, weight loss, swelling, mechanical, adhesion and bioactivity was analyzed. In particular, bioactivity tests revealed that upon immersion in simulated body fluid, there was the formation of a bone-like apatite layer. Moreover, upon 16 h in direct contact with Staphylococcus aureus and Escherichia coli cultures, these FS films exhibited a clear antibacterial effect. Therefore, such bioactive, antibacterial and adhesive free-standing films could potentially be used as temporary guided bone regeneration films, in particular to regenerate small bone defects and also periodontal tissues.

Bioglass nanoparticles (BGs) are of outmost importance in the biomedical field, because their unique characteristics, namely osteoconductivity and osteoinductivity, and also in certain conditions, angiogenic and bactericidal properties. In this work, novel bioglass nanoparticles containing silver (AgBGs) were synthesized by a sol-gel method, adopting different thermal treatments to obtain new nanoparticles with bioactive and antibacterial features. This is the first systematic study of the effect of the thermal treatment on the properties of AgBGs. The effect of the studied thermal treatments on the properties of synthesized nanoparticles was analyzed by several characterization techniques: FT-IR, XRD, STEM , SEM-EDS and Zeta potential. FT-IR allowed the identification of the characteristic peaks of the nanoparticles and XRD revealed the presence of the characteristic peaks of an apatite-like phase. By STEM analysis it was found that the produced nanoparticles are dense and have a diameter < 200 nm. The SEM micrographs showed their surface morphology and Zeta potential measurements were performed to study their suspension stability. Additionally, in vitro bioactivity tests confirmed their bioactive potential and the microbiological tests evidenced their bactericidal effect. These promising AgBGs could be incorporated either in 2D or 3D structures for several biomedical applications, namely in the orthopedic and dental fields.

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