Bacterial attachment on titanium and tantalum for bone tissue engineering applications

Titanium and tantalum have been widely employed in many load-bearing orthopaedic applications due to their excellent mechanical properties and corrosion stability. However, the problem associated with post implant infections persists even though considerable research and development efforts have been made. Infections could be minimized by designing an implant material that could have a less favourable environment surface for bacterial attachment which was known as the primary condition for any implant-associated infections. In this study, titanium and tantalum were mechanically polished and characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy, profilometry, and surface wettability to compare with unpolished surfaces (noted as as-received). To evaluate the extent of bacterial attachment on these surfaces, bacterial strain Pseudomonas aeruginosa ATCC 9027 was used. Quantification of bacterial attachment was done using confocal laser scanning microscopy and scanning electron microscopy. Results indicate that surface roughness played a significant role in the adherence of P. aeruginosa to titanium and tantalum, while surface wettability property showed a little correlation with bacterial retention. Also, as-received and polished tantalum samples have fewer tendencies to bacterial attachment compared to their titanium counterpart.</p

A review on bioactive porous metallic biomaterials

Porous metallic biomaterials have been extensively studied for many bone tissue engineering applications because porous structures provided space for bone in-growth and vascularisation. Improvement on mechanical properties also leads to the increased popularity of porous materials for bone substitute applications, especially for load-bearing implants. However, they usually lack sufficient osseointegration for implant longevity. In addition, their biocompatibility is also an important concern in these applications due to adverse reactions of metallic ions with the surrounding tissues after these metallic ions are released from the implant surfaces. One consideration to accelerate the healing process is surface treatment, including application of bioactive coatings, e.g. hydroxyapatite and biomimetic creation of surface. Surface treatments on biomaterials will determine surface chemistry and topography, whereas these surface characteristics influence osseointegration process. To respond on the challenges of producing biocompatible and mechanical compatible biomaterials and lack of review studies on surface modifications on porous structures, a comprehensive literature review on surface modifications of various porous metallic materials is presented. This review covers various methods of surface treatment such as biomimetic, electrodeposition, alkali heat treatment, anodization and their effects on mechanical and structural properties which then provided insights into bone implants improvement studies. Biological responses (in vitro and In vivo) of porous material after surface treatment are thoroughly discussed

Investigation of bacterial attachment on hydroxyapatite-coated titanium and tantalum

Titanium and tantalum have been widely employed in many load-bearing orthopaedic applications due to their excellent strength and corrosion resistance. The bio-function properties of titanium and tantalum can be enhanced to improve the healing process after implantation by incorporating a bioactive coating onto their surfaces. For this purpose, thin films of 200 nm thick silicon dioxide (SiO2) and 2 &#0181;m thick hydroxyapatite (HA) were deposited onto titanium and tantalum surfaces using electron beam evaporation and magnetron sputtering, respectively. The surface morphology, elemental composition and crystal structure of HA-SiO2 coated titanium and tantalum were characterised using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry. Pseudomonas aeruginosa and Staphylococcus aureus strains were used to investigate the bacterial attachment onto these surfaces. The HA thin films deposited onto titanium and tantalum surfaces were homogenous. The desirable crystalline phase of HA was also identified on the titanium and tantalum surfaces. Bacterial attachment results indicate that HA-SiO2 coated surfaces were less preferable for the adhesion of bacteria compared to the non-coated surfaces

Bone Tissue Engineering via Carbon‐Based Nanomaterials

Bone tissue engineering (BTE) has received significant attention due to its enormous potential in treating critical-sized bone defects and related diseases. Traditional materials such as metals, ceramics, and polymers have been widely applied as BTE scaffolds; however, their clinical applications have been rather limited due to various considerations. Recently, carbon-based nanomaterials attract significant interests for their applications as BTE scaffolds due to their superior properties, including excellent mechanical strength, large surface area, tunable surface functionalities, high biocompatibility as well as abundant and inexpensive nature. In this article, recent studies and advancements on the use of carbon-based nanomaterials with different dimensions such as graphene and its derivatives, carbon nanotubes, and carbon dots, for BTE are reviewed. Current challenges of carbon-based nanomaterials for BTE and future trends in BTE scaffolds development are also highlighted and discussed