The Impact of EBM-Manufactured Ti6Al4V ELI Alloy Surface Modifications on Cytotoxicity toward Eukaryotic Cells and Microbial Biofilm Formation

Abstract

Electron beam melting (EBM) is an additive manufacturing technique, which allows forming customized implants that perfectly fit the loss of the anatomical structure of bone. Implantation efficiency depends not only on the implant’s functional or mechanical properties but also on its surface properties, which are of great importance with regard to such biological processes as bone regeneration or microbial contamination. This work presents the impact of surface modifications (mechanical polishing, sandblasting, and acid-polishing) of EBM-produced Ti6Al4V ELI implants on essential biological parameters. These include wettability, cytotoxicity toward fibroblast and osteoblast cell line, and ability to form biofilm by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Obtained results indicated that all prepared surfaces exhibited hydrophilic character and the highest changes of wettability were obtained by chemical modification. All implants displayed no cytotoxicity against osteoblast and fibroblast cell lines regardless of the modification type. In turn, the quantitative microbiological tests and visualization of microbial biofilm by means of electron microscopy showed that type of implant’s modification correlated with the species-specific ability of microbes to form biofilm on it. Thus, the results of the presented study confirm the relationship between such technological aspects as surface modification and biological properties. The provided data are useful with regard to applications of the EBM technology and present a significant step towards personalized, customized implantology practice.

3D Printing of Thermoresponsive Hydrogel Laden with an Antimicrobial Agent towards Wound Healing Applications

“…The protocol for the determination of the hydrogel's cytotoxicity was based on the previous study by Junka's group [45,46]. The normative neutral red (NR) cytotoxicity assay was performed in fibroblast (L929, ATCC, Manassas, VA, USA) cell cultures treated with extracts from hydrogel samples prepared according to the ISO 10993 norm: Biological evaluation of medical devices; Part 5: Tests for in vitro cytotoxicity; Part 12: Biological evaluation of medical devices, sample preparation, and reference materials (ISO 10993-5:2009 and ISO/IEC 17025:2005).…”

Toward Bactericidal Enhancement of Additively Manufactured Titanium Implants

“…However, it is worth noting that sandblasting may increase the risk of bacterial adhesion on the implant surface if the sandblasting medium is not adequately removed [66,69]. Interestingly, Szymczyk-Ziolkowska et al [70] found that different microorganisms have a species-specific ability to form biofilms on different types of implant modification. For patients with a history of S. aureus, Pseudomonas aeruginosa, or Candida albicans infection, the use of as-built, sandblasted, or acid-etched alloys are not recommended, respectively.…”

Influence of building direction on physical and mechanical properties of titanium implants: A systematic review

“…The thickness of each layer impacts the accuracy and printing time, with smaller layers resulting in a more detailed surface finish. The number and speed of scans refer to the frequency and speed with which the beam strikes the part, and can affect the material density, adhesion between layers, modulus of elasticity, mechanical strength, and fatigue of the implant [ 2 , [16] , [17] , [18] , [19] , [21] , [22] , [23] , [24] , [25] , [26] ].…”

“…Building direction is characterized by the orientation in which the layers of the material are deposited during the manufacturing process and can affect the mechanical strength, fatigue, density, and surface characteristics of the part [ 2 , 25 , 27 ], being able to lead to decreased corrosion resistance, changes in tensile behavior and structural anisotropies [ [28] , [29] , [30] , [31] , [32] , [33] ]. Anisotropy is characterized by the presence of variations in the physical and mechanical properties of the implant in different directions and axes, resulting in distinct behaviors and implications for its clinical performance [ [34] , [35] , [36] ].…”

“…It should be noted that modifying a single parameter, such as the printing angle, can influence both the macro and final microstructure of the surfaces, affecting these properties and potentially impacting the success of implants. Among the most reported axes in the literature are X, Y, and Z, represented by horizontal (0°), vertical (90°), and diagonal (45°) positions, respectively [ 3 , 25 , 30 , [37] , [38] , [39] ]. Thus, the present systematic review started from the hypothesis that the direction of the impression angle of titanium implants influences their physical-mechanical properties.…”