During the last decades, the continuous population aging led to a significant increase in bone fracture, as well as of musculoskeletal diseases. This phenomenon, due to the weakening of skeleton and immune system of the elder patients, has been negatively impacting on the quality of life of many people, in addition to overloading the public healthcare system worldwide.
Various materials have been developed and optimized to repair or substitute bone. However, based on relevant clinical studies in the field, among the numerous developed materials, a poor correlation between in vitro and in vivo outcomes was observed, suggesting a low significance and predictability of the current in vitro testing system.
Such poor correlation can be explained by the limited knowledge available on biomaterials-proteins interactions. The implant, indeed, does not directly interact with cells, but this interaction is mediated by the proteins adhering on its surface. Proteins adsorption (or lack thereof) at the surface of the material and their self-organization are crucial in determining the cells fate. Furthermore, if cells do not properly colonize the implant, the surface is available for bacteria to adhere and proliferate.
In her doctoral dissertation, MSc Virginia Alessandra Gobbo focused on two classes of biomaterials: bioactive glasses (BGs) and titanium alloys. BGs are a relatively recent class of biomaterials, some of which are already commercially available and clinically used as bone fillers to treat bone defects. They promote bone regeneration and are highly versatile, therefore being promising in a myriad of applications.
“Conversely, titanium alloys are well-characterized and have been widely used as a support for bone reconstruction. Nowadays they are broadly applied for joint replacements and dental implants. However, despite the efficacy of titanium alloys in supporting bone fracture healing, its non-bioactive surface is not always leading to osteointegration and sometimes this leads to bacterial infection”, Gobbo says.
Gobbo’s thesis aims at controlling the surface physicochemical properties of BGs and titanium alloys to reach two main goals: 1) evaluating protein adsorption to control or even predict the biological response, and 2) adding beneficial bioactive properties to titanium alloys while targeting the grafting of specific antimicrobial peptides for limiting bacteria adhesion and proliferation and, consequently, the risk of infection.
Overall, surface modification of biomaterials was found effective in controlling protein adsorption to gain the desired biological response, i.e., cell alignment and antibacterial activity.
“This is a step forward in improving the predictability of in vivo outcomes. This thesis also demonstrated the possibility to develop bioactive biomaterials with added functionality by grafting biomolecules of interest, opening the path as well to patient-specific implants", Gobbo says.
Public defence on Friday 14 June
The doctoral dissertation of MSc Virginia Alessandra Gobbo in the field of Biomaterial Sciences titled Surface Modification of Bioactive Glasses and Titanium Alloys for Controlled Proteins Adsorption: Towards predictable cell and bacteria fate will be publicly examined in the Faculty of Medicine and Health Technology at Tampere University at 12:00 on Friday 14.6.2024 at Hervanta campus in Tietotalo building, auditorium TB109 (Korkeakoulunkatu 1, 33720 Tampere). The Opponent will be PhD Hanna Tiainen, University of Oslo, Institute of Clinical Dentistry. The Custos will be Prof. Jonathan Massera, Faculty of Medicine and Health Technology, Tampere University.