Bacterial Biofilms and Titanium Implants: Current Understanding, Clinical Challenges, and Emerging Surface Modification Strategies

Biofilms are complex microbial structures embedded in an extracellular matrix, exhibiting high resistance to antibiotics and host immune responses. Biofilm-associated infections on implant surfaces remain a major clinical challenge, often requiring implant removal and significantly affecting patient outcomes.
This systematic review aims to evaluate the influence of biomaterial type and surface properties on bacterial adhesion and biofilm formation, as well as to assess current strategies for improving the antibacterial performance of titanium-based implants.
A systematic literature review was conducted focusing on studies investigating biofilm formation on implant materials, including metals, polymers, ceramics, and composites. Particular attention was given to titanium alloys and surface modification techniques such as micro-arc oxidation and electrophoretic deposition. Key parameters analyzed included surface roughness, wettability, chemical composition, and surface energy.
The reviewed studies indicate that bacterial colonization is strongly influenced by both material type and surface characteristics. Although titanium and its alloys are widely used due to their favorable mechanical and biological properties, conventional Ti–6Al–4V alloys present limitations related to potential toxicity and susceptibility to biofilm formation. Emerging titanium alloys incorporating biocompatible elements such as niobium and zirconium demonstrate improved biological safety. Surface modification strategies, particularly composite coatings combining antibacterial agents and osteogenic properties, show promising results in reducing infection risk. However, commonly used antibacterial elements such as silver, copper, and zinc may present challenges related to cytotoxicity and long-term stability.
Material composition and surface engineering play a critical role in biofilm prevention on implant surfaces. Advanced titanium alloys and multifunctional surface modifications represent promising directions, though further research is required to develop stable, non-toxic, and clinically effective antibacterial solutions.