Publicação
Surface functionalization with antibacterial and bioactive compounds using hybrid techniques (subtractive and addictive) via laser for the improvement of knee prostheses properties
| Resumo: | Knee arthroplasty is a surgical procedure that consists in the removal of the entirety or part of the knee joint, extracting damaged cartilage and replacing it with a prosthesis or implant. Thus, knee prostheses are devices that replace the function of the joint. They have different components, each with a specific function and composed of different materials. However, their longevity is still relatively short, about 15 years, and the use of materials with inadequate mechanical properties can lead to the appearance of undesirable phenomena that contribute to an even earlier prosthesis removal. That being said, it is important to find solutions to improve not only the functionality of these implants, but also their longevity. Therefore, this work focuses on the modification of materials typically used in these implants, such as zirconia and titanium, through a hybrid (subtractive and additive) laser processing technique. Patterns were thus created on the surface of the materials, and bioactive compounds (hydroxyapatite and mineral trioxide aggregate) were incorporated into them, in order to improve the bioactivity and consequent functionality and longevity of the knee prostheses. Firstly, samples of the base materials in question were created and textured using different strategies and varying laser parameters such as power, speed and number of passes. The bioactive materials were then deposited and incorporated on the surface of the samples using different techniques, such as CO2 laser sintering, conventional furnace method or deposition using a spatula. Finally, mechanical tests were performed in order to analyse and evaluate the properties of the produced samples. These include SEM-EDS, wettability, friction tests and cell viability tests. Results show that the laser texturing was considered an effective and reliable method to produce different structures throughout the samples without compromising its mechanical properties. The employed functionalization techniques were successful, as mechanically interlocked and thick coatings were created. The incorporation of said coatings had a significant effect on the surface energy of the samples, since wettability tests showed that contact angle of the samples is reduced after the addition of the bioactive layer. Friction tests comproved the adherence of bone to the surface of functionalized samples, while biological tests revealed the bioactive potencial of the MTA coating. In conclusion, textured samples were successfully produced and afterwards functionalized using different techniques. These surfaces showed promising results in both mechanical and biological tests, as this new approach for the development of functionalized knee prostheses is validated. |
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| Autores principais: | Barbosa, Gonçalo Garrett Miranda Ribeiro |
| Assunto: | Surface functionalization Hybrid laser Bioactivity Knee prostheses Zirconia Titanium Funcionalização superficial Laser híbrido Bioatividade Prótese Zircónia Titânio |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Knee arthroplasty is a surgical procedure that consists in the removal of the entirety or part of the knee joint, extracting damaged cartilage and replacing it with a prosthesis or implant. Thus, knee prostheses are devices that replace the function of the joint. They have different components, each with a specific function and composed of different materials. However, their longevity is still relatively short, about 15 years, and the use of materials with inadequate mechanical properties can lead to the appearance of undesirable phenomena that contribute to an even earlier prosthesis removal. That being said, it is important to find solutions to improve not only the functionality of these implants, but also their longevity. Therefore, this work focuses on the modification of materials typically used in these implants, such as zirconia and titanium, through a hybrid (subtractive and additive) laser processing technique. Patterns were thus created on the surface of the materials, and bioactive compounds (hydroxyapatite and mineral trioxide aggregate) were incorporated into them, in order to improve the bioactivity and consequent functionality and longevity of the knee prostheses. Firstly, samples of the base materials in question were created and textured using different strategies and varying laser parameters such as power, speed and number of passes. The bioactive materials were then deposited and incorporated on the surface of the samples using different techniques, such as CO2 laser sintering, conventional furnace method or deposition using a spatula. Finally, mechanical tests were performed in order to analyse and evaluate the properties of the produced samples. These include SEM-EDS, wettability, friction tests and cell viability tests. Results show that the laser texturing was considered an effective and reliable method to produce different structures throughout the samples without compromising its mechanical properties. The employed functionalization techniques were successful, as mechanically interlocked and thick coatings were created. The incorporation of said coatings had a significant effect on the surface energy of the samples, since wettability tests showed that contact angle of the samples is reduced after the addition of the bioactive layer. Friction tests comproved the adherence of bone to the surface of functionalized samples, while biological tests revealed the bioactive potencial of the MTA coating. In conclusion, textured samples were successfully produced and afterwards functionalized using different techniques. These surfaces showed promising results in both mechanical and biological tests, as this new approach for the development of functionalized knee prostheses is validated. |
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