A call for action to the biomaterial community to tackle antimicrobial resistance

The global surge of antimicrobial resistance (AMR) is a major concern for public health and proving to be a key challenge in modern disease treatment, requiring action plans at all levels. Microorganisms regularly and rapidly acquire resistance to antibiotic treatments and new drugs are continuously required. However, the inherent cost and risk to develop such molecules has resulted in a drying of the pipeline with very few compounds currently in development. Over the last two decades, efforts have been made to tackle the main sources of AMR. Nevertheless, these require the involvement of large governmental bodies, further increasing the complexity of the problem. As a group with a long innovation history, the biomaterials community is perfectly situated to push forward novel antimicrobial technologies to combat AMR. Although this involvement has been felt, it is necessary to ensure that the field offers a united front with special focus in areas that will facilitate the development and implementation of such systems. This paper reviews state of the art biomaterials strategies striving to limit AMR. Promising broad-spectrum antimicrobials and device modifications are showcased through two case studies for different applications, namely topical and implantables, demonstrating the potential for a highly efficacious physical and chemical approach. Finally, a critical review on barriers and limitations of these methods has been developed to provide a list of short and long-term focus areas in order to ensure the full potential of the biomaterials community is directed to helping tackle the AMR pandemic

Modelling the growth of hydrothermally synthesised bactericidal nanostructures, as a function of processing conditions

In recent times, large research focus has been placed on nanostructured materials as a method of killing bacteria. Previous work in this area has found that hydrothermally synthesised TiO2 nanostructures show antibacterial behaviour against Gram-positive and Gram-negative bacteria strains. Various sources postulate that certain surface properties, such as wettability and structure dimensions are responsible for, and influence bactericidal efficiency of nanostructured surfaces. Our most recent work found that bactericidal efficiency is statistically linked to nanostructure height, leading to the demand for a method of predicting and designing nanostructure height prior to fabrication. This work uses experimental data from hydrothermal synthesis processes, in combination with IBM SPSS Statistics to form a prediction of nanostructure height, as a function of hydrothermal process parameters (NaOH concentration, reaction time and reaction temperature). Experimental validation shows that the model has a 0.5–8.5% error, accurately predicting the height of TiO2 structures formed via hydrothermal synthesis. In addition, these samples exhibited bactericidal behaviour against both S. aureus and P. aeruginosa bacterial cells

Recent advances in manufacturing and surface modification of titanium orthopaedic applications

Implant failure is a common problem in orthopedic applications, which causes pain and stress for patients, prolonged antibiotic therapy, increased time and cost of hospitalization, and revision surgery. Selecting the optimum porous structure, manufacturing process and surface modification approach is crucial to reduce the rate of implant failure. The design of porous structures in orthopedic implants plays an important role in vascularization, diffusion of nutrients, and in the relationship between implants and osteoblasts. Common techniques for porous design are computer aided design (CAD), image based design, implicit surface design, and topology optimization. Metal-based additive manufacturing methods such as electron beam melting (EBM), selective laser melting (SLM) and selective laser sintering (SLS) have been extensively developed for fabrication of porous structures on Titanium. Several chemical surface modification methods are used, such as acid etching, anodization, and coatings, to improve mechanical properties, biocompatibility, increase surface roughness, and to promote osseointegration and bone regrowth. This paper reviews the design and manufacturing of porous implant material via additive manufacturing techniques, as well as recent advances in surface modification, to achieve biocompatible surfaces. The outcome of this research will provide an effective strategy for manufacturing, and surface modification of titanium orthopedic implants