BAMBBI · Bio-inspired AntiMicrobial Bone BIoceramics: Deciphering contact-based biocidal mechanisms

Bacterial bone infections are one of the great challenges of orthopaedic and maxillofacial surgery, aggravated by antibiotic resistance, a serious health threat responsible for 700,000 deaths per year. The recent discovery of the bactericidal properties of some naturally occurring surface topographies has opened a new avenue of research. However, there is incomplete knowledge of the mechanisms of action and too many unanswered questions to translate these advances into clinical use. BAMBBI aims to tackle this challenge by developing synthetic bone grafts featuring contact-based antimicrobial properties, adding antimicrobial activity to their capacity to support bone regeneration. Using a novel bottom-up approach inspired in biomineralization routes, I intend to engineer the surface of calcium phosphates with an unprecedented and fine control of nanotopography by harnessing the power of ions and organic molecules (e.g. amino acids, calcium chelators and surfactants) to drive crystal nucleation and growth. Moreover, we will further enhance the antimicrobial effect by exploiting the synergy with chemical moieties to modulate bacterial affinity for the surface and/or confer additional antimicrobial properties by immobilisation of antimicrobial peptides. This will provide us with a platform to study the contact-based bactericidal mechanisms in depth and unravel the role of nanotopography and surface chemistry and their interplay with the intrinsic properties of bacteria. Only considering all these parameters will it be possible to unveil the causes of the substantial differences in bactericidal efficacy of a given substrate for different bacteria and design more efficient antibacterial surfaces. In addition to being a major breakthrough in the field of bone regeneration, the progress in new methods of fine-tuning the nanostructure of calcium phosphates will have an impact in very diverse fields such as catalysis, water purification and protein separation.