Una presunta disputa di scuola in Gai., inst. 3.147

FULL TEXT PD

Three-dimensional cell culture of human mesenchymal stem cells in nanofibrillar cellulose hydrogels

Human mesenchymal stem cells (MSCs) are the most intensely studied and clinically used adult stem cell type. Conventional long-term cultivation of MSCs as a monolayer is known to result in a reduction of their functionality and viability. In addition, large volumes of cell culture medium are required to obtain cell quantities needed for their clinical use. In this proof of concept study, we cultivated human MSCs within a 3D nanofibrillar cellulose (NFC) hydrogel. We show that NFC is biocompatible with human MSCs, and represents a feasible approach to upscaling of their culture

Multiplex boundary work in innovation projects: the role of collaborative spaces for cross-functional and open innovation

Purpose This study investigates the role of collaborative spaces as organizational support for internal innovation through cross-functional teams and for open innovation with external stakeholders. In particular, the study focuses on collaborative spaces as tools for multiplex (i.e., simultaneous internal and external boundary management in innovation projects). Design/methodology/approach The authors conducted a qualitative study in a multi-divisional organization that set up in its headquarters a collaborative space for collaborative product development. Data were collected through semi-structured interviews and participant observations. Findings Findings highlight that the relation between expectations and experiences about the collaborative space impact on employees\u27 ability to perform boundary work inside and outside the organization. In addition to the collaborative space\u27s affording role for expectations about hands-on collaborative innovation (space as laboratory), the study also highlights a set of collaboration constraints. These latter are generated by perceived boundary configurations (i.e. degree of boundary permeability and infrastructure in internal and external collaborations) and by discrepancies between expectations (space as laboratory) and actual collaboration experiences in the space (i.e. space as maze, cloister, showcase and silo). We show that space-generated constraints slow down internal and external boundary work for innovation and generate a trade-off between them. Originality/value Using the process-based perspective of boundary work, the paper connects studies on cross-functional teaming and open innovation through the concept of “multiplex boundary work.” It also contributes to the literature on boundary work by showing the challenges of using collaborative spaces as organizational support tools for multiplex boundary spanning

Antioxidant Activity of Silica-Based Bioactive Glasses

Bioactive glasses are the materials of choice in the field of bone regeneration. Antioxidant properties of interest to limit inflammation and foreign body reactions have been conferred to bioactive glasses by the addition of appropriate ions (such as Ce or Sr). On the other hand, the antioxidant activity of bioactive glasses without specific ion/molecular doping has been occasionally cited in the literature but never investigated in depth. In the present study, three silica-based bioactive glasses have been developed and characterized for their surface properties (wettability, zeta potential, chemical composition, and reactivity) and radical scavenging activity in the presence/absence of cells. For the first time, the antioxidant activity of simple silica-based (SiO2-CaO-Na2O) bioactive glasses has been demonstrated

Nano-topography and functionalization with the synthetic peptoid GN2-Npm9 as a strategy for antibacterial and biocompatible titanium implants

In recent years, antimicrobial peptides (AMPs) have attracted great interest in scientific research, especially for biomedical applications such as drug delivery and orthopedic applications. Since they are readily degradable in the physiological environment, scientific research has recently been trying to make AMPs more stable. Peptoids are synthetic N-substituted glycine oligomers that mimic the structure of peptides. They have a structure that does not allow proteolytic degradation, which makes them more stable while maintaining microbial activity. This structure also brings many advantages to the molecule, such as greater diversity and specificity, making it more suitable for biological applications. For the first time, a synthesized peptoid (GN2-Npm9) was used to functionalize a nanometric chemically pre-treated (CT) titanium surface for bone-contact implant applications. A preliminary characterization of the functionalized surfaces was performed using the contact angle measurements and zeta potential titration curves. These preliminary analyses confirmed the presence of the peptoid and its adsorption on CT. The functionalized surface had a hydrophilic behaviour (contact angle = 30°) but the hydrophobic tryptophan-like residues were also exposed. An electrostatic interaction between the lysine residue of GN2-Npm9 and the surface allowed a chemisorption mechanism. The biological characterization of the CT_GN2-Nmp9 surfaces demonstrated the ability to prevent surface colonization and biofilm formation by the pathogens Escherichia coli and Staphylococcus epidermidis thus showing a broad-range activity. The cytocompatibility was confirmed by human mesenchymal stem cells. Finally, a bacteria-cells co-culture model was applied to demonstrate the selective bioactivity of the CT_GN2-Nmp9 surface that was able to preserve colonizing cells adhered to the device surface from bacterial infection

Electron beam structuring of Ti6Al4V: New insights on the metal surface properties influencing the bacterial adhesion

Soft tissue adhesion and infection prevention are currently challenging for dental transmucosal or percutaneous orthopedic implants. It has previously been shown that aligned micro-grooves obtained by Electron Beam (EB) can drive fibroblast alignment for improved soft tissue adhesion. In this work, evidence is presented that the same technique can also be effective for a reduction of the infection risk. Grooves 10-30 \u3bcm wide and around 0.2 \u3bcm deep were obtained on Ti6Al4V by EB. EB treatment changes the crystalline structure and microstructure in a surface layer that is thicker than the groove depth. Unexpectedly, a significant bacterial reduction was observed. The surfaces were characterized by field emission scanning electron microscopy, X-ray diffraction, confocal microscopy, contact profilometry, wettability and bacterial adhesion tests. The influence of surface topography, microstructure and crystallography on bacterial adhesion was systematically investigated: it was evidenced that the bacterial reduction after EB surface treatment is not correlated with the grooves, but with the microstructure induced by the EB treatment, with a significant bacterial reduction when the surface microstructure has a high density of grain boundaries. This correlation between microstructure and bacterial adhesion was reported for the first time for Ti alloys