Cytotoxicity investigation of a new hydroxyapatite scaffold with improved structural design

Introduction Biodegradable porous scaffolds are found to be very promising bone substitutes, acting as a temporary physical support to guide new tissue regeneration, until the entire scaffold is totally degraded and replaced by the new tissue. Objective The aim of this study was to investigate cytotoxicity of a synthesized calcium hydroxyapatite-based scaffold, named ALBO-OS, with high porosity and optimal topology. Methods The ALBO-OS scaffold was synthesized by the method of polymer foam template. The analysis of pore geometry and scaffold wallstopography was made by scanning electron microscope (SEM). The biological investigations assumed the examinations of ALBO-OS cytotoxicity to mouse L929 fibroblasts, using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidefor (MU) and lactate dehydrogenase (LDH) tests and inverse phase microscopy. Results The SEM analysis showed high porosity with fair pore distribution and interesting morphology from the biological standpoint. The biological investigations showed that the material is not cytotoxic to L929 cells. Comparison of ALBO-OS with Bio-Oss, as the global gold standard as a bone substitute, showed similar results in MTT test, while LDH test showed significantly higher rate of cell multiplication with ALBO-OS. Conclusion The scaffold design from the aspect of pore size, distribution, and topology seems to be very convenient for cell adhesion and occupation, which makes it a promising material as a bone substitute. The results of biological assays proved that ALBO-OS is not cytotoxic for L929 fibroblasts. In comparison with Bio-Oss, similar or even better results were obtained

Investigation of Ion Release and Antibacterial Properties of TiN-Cu-Nanocoated Nitinol Archwires

Background: The use of nitinol (NiTi) archwires in orthodontic treatment has increased significantly due to unique mechanical properties. The greatest obstacle for safe orthodontic treatment is chemically or microbiologically induced corrosion, resulting in nickel (Ni) release. The aim of this investigation was to enhance corrosion resistance and introduce antibacterial properties to NiTi archwires by coating them with copper (Cu) doper titanium nitride (TiN-Cu). Methods: NiTi archwires were coated with TiN-Cu using cathodic arc evaporation (CAE) and direct current magnetron sputtering (DC-MS). The morphology of the sample was analyzed via field emission scanning electron microscopy (FESEM) and chemical composition was assessed using energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR). Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to estimate the ion release. The biocompatibility of samples was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT) assay. Antibacterial activity was tested against Streptococcus mutans and Streptococcus mitis. Results: Physicochemical characterization revealed well-designed coatings with the presence of TiN phase with incorporated Cu. TiN-Cu-nanocoated archwires showed a statistically lower Ni release (p < 0.05). Relative cell viability was the highest in 28-day eluates of TiN-Cu-nanocoated archwires (p < 0.05). The most remarkable decrease in Streptococcus mitis concentrations was observed in the case of TiN-Cu-coated archwires (p < 0.05). Conclusion: Taking into account biocompatibility and antibacterial tests, TiN-Cu-nanocoated archwires may be considered as a good candidate for further clinical investigation

Mg Substituted Hydroxyapatite for Application in Bone Tissue Engineering

Magnesium (Mg) is an essential element in the human body primarily stored in bones. Mg ions have many potential benefits for bone tissue showing excellent osteogenic inductivity [1]. The aim of this study was to synthesize Mg substituted hydroxyapatite (Mg-HAP) for application in bone tissue engineering and to assess its behaviour in conditions mimicking physiological ones. Mg-HAP was synthesized using reflux method and its structural and morphological characterization was performed by XRD, FTIR and SEM. The changes in local structure and composition after irradiation and immersion in physiological solution and simulated fluid were assessed by electron paramagnetic resonance (EPR) spectroscopy. The results of EPR analysis pointed out that irradiation did not change the composition and structure of Mg-HAP. After immersion in model media (simulated body fluid and saline solution), the small amount of by-product of synthesis disappeared after 24 h and Mg-HAP remained the only phase. Also, the radical signals in EPR spectra faded away after 28 days in model media, showing that the structure and composition of Mg-HAP both went through a kind of stabilization in simulated physiological conditions. These results make the investigated Mg-HAP promising material for application in bone tissue engineering

Mg Substituted Hydroxyapatite for Application in Bone Tissue Engineering

Magnesium (Mg) is an essential element in the human body primarily stored in bones. Mg ions have many potential benefits for bone tissue showing excellent osteogenic inductivity [1]. The aim of this study was to synthesize Mg substituted hydroxyapatite (Mg-HAP) for application in bone tissue engineering and to assess its behaviour in conditions mimicking physiological ones. Mg-HAP was synthesized using reflux method and its structural and morphological characterization was performed by XRD, FTIR and SEM. The changes in local structure and composition after irradiation and immersion in physiological solution and simulated fluid were assessed by electron paramagnetic resonance (EPR) spectroscopy. The results of EPR analysis pointed out that irradiation did not change the composition and structure of Mg-HAP. After immersion in model media (simulated body fluid and saline solution), the small amount of by-product of synthesis disappeared after 24 h and Mg-HAP remained the only phase. Also, the radical signals in EPR spectra faded away after 28 days in model media, showing that the structure and composition of Mg-HAP both went through a kind of stabilization in simulated physiological conditions. These results make the investigated Mg-HAP promising material for application in bone tissue engineering

Magnesium substituted hydroxyapatite for biomedical application

As magnesium is an important trace element in bone and teeth, and plays a key role in bone metabolism, the aim of this study was to obtain magnesium substituted hydroxyapatite (MgHAP) and to assess its application potential. Upon synthesis, the changes in local structure and composition after irradiation and immersion in physiological solution and simulated fluid were followed by electron paramagnetic resonance (EPR) spectroscopy. Samples were also characterized by XRD, FTIR, SEM, EDS, AAS and TGA. The results showed that irradiation did not affect the composition and structure of Mg-HAP. After immersion in model media, the small amount of by-product of synthesis disappeared already after 24 h and Mg-HAP remained as the only phase. Also, the radical signals in EPR spectra faded or completely disappeared after 28 days in model media, which could indicate that the structure and composition of Mg-HAP both went through a kind of stabilization in conditions mimicking physiological ones. All these indicate that investigated Mg-HAP has good potential for biomedical application considering its behaviour in model media which imitate physiological conditions.X Serbian Ceramic Society Conference - Advanced Ceramics and Application : new frontiers in multifunctional material science and processing : program and the book of abstracts; September 26-27, 2022; Belgrad

Behaviour of Mg and Si Substituted Hydroxyapatites in Model Media

Thanks to its similarity with biological apatite found in vertebrate hard tissues, calcium hydroxyapatite is one of the most investigated materials in bone tissue engineering. Since biological apatite is not stoichiometric, ion substituted hydroxyapatites are in the focus of many studies as they more closely mimic the composition of natural bone. Although there are many investigations of the influence of foreign ions on the structure and physico-chemical properties of ionsubstituted hydroxyapatites, there is no much information on their behaviour in different media. In present study, magnesium - which plays a key role in bone metabolism and silicon - which is necessary for normal skeletal development, were used as ion substitutes. The behaviour of Mg and Si substituted hydroxyapatite in simulated body fluid and physiological solution was investigated by XRD, FTIR and SEM. Obtained results confirmed great potential of these substituted hydroxyapatites for biomedical applications.VI Conference of The Serbian Society for Ceramic Materials, 6CSCS-2022, June 28-29, 2022, Belgrade, Serbi

Mg and Si substituted hydroxyapatite: Behaviour in simulated body fluid

Due to its similarity with biological apatite found in vertebrate hard tissues, calcium hydroxyapatite is one of the most investigated materials in bone tissue engineering. As the biological apatite is not stoichiometric, ion substituted hydroxyapatites attract much atention since they more closely mimic the composition of natural bone. Although there are many investigations of the influence of foreign ions on the structure and physico-chemical properties of ion-substituted hydroxyapatites, there is scarse information on their behaviour in different media. In the present study, magnesium (Mg), that plays a key role in bone metabolism and silicon (Si), that is necessary for normal skeletal development, were used as ion substitutes. The behaviour of Mg and Si substituted hydroxyapatite in simulated body fluid was investigated by XRD, FTIR and SEM. Obtained results confirmed great potential of these substituted hydroxyapatites for biomedical applications.Due to its similarity with biological apatite found in vertebrate hard tissues, calcium hydroxyapatite is one of the most investigated materials in bone tissue engineering. As the biological apatite is not stoichiometric, ion substituted hydroxyapatites attract much atention since they more closely mimic the composition of natural bone. Although there are many investigations of the influence of foreign ions on the structure and physico-chemical properties of ion-substituted hydroxyapatites, there is scarse information on their behaviour in different media. In the present study, magnesium (Mg), that plays a key role in bone metabolism and silicon (Si), that is necessary for normal skeletal development, were used as ion substitutes. The behaviour of Mg and Si substituted hydroxyapatite in simulated body fluid was investigated by XRD, FTIR and SEM. Obtained results confirmed great potential of these substituted hydroxyapatites for biomedical applications

Kalcijumfosfatni materijali u inženjerstvu koštanog tkiva

Calcium phosphates, together with polymers, are most commonly used materials in bone engineering since their composition is similar to bone. They are used to fulfill various defects caused by injury or bone disease, as well as for the preparation of endodontic mixtures. Because of their great importance in dentistry, these materials are given special attention in the current paper. This paper is a part of the monograph entitled 'Nanomedicine, the Greatest Challenge of the 21st Century', which attracted great interest of technical and professional communities in different areas of medicine. Also for the last two years this book is promoted by the Student Cultural Centre as the only national book chosen in the narrowest election. That fact is very important for young researchers who study tissue engineering, endodontics and implantology.Kalcijum- fosfati, zajedno s nekim polimerima, najviše su korišćeni materijali u inženjerstvu koštanog tkiva, budući da su po sastavu bliski prirodnoj kosti. Koriste se za ispune različitih oštećenja nastalih usled povreda ili bolesti koštanog tkiva, kao i za pripremu endodontskih mešavina za primenu u stomatologiji. Zbog izuzetnog značaja u stomatologiji, kalcijumfosfatni materijali zaslužuju posebno mesto, pa će im u okviru ovog rada, ali i radova koji će uslediti, biti posvećena posebna pažnja. Radovi su najvećim delom sastavni deo monografije pod nazivom 'Nanomedicina, najveći izazov 21. veka', koja je pobudila veliko interesovanje stručne i profesionalne javnosti usmerene ka različitim oblastima medicine i koju je već dve godine zaredom Studentski kulturni centar, kao jedinu knjigu domaćeg autora, promovisao kao knjigu najužeg izbora. Verujemo da je ta činjenica posebno važna za mlađe istraživače koji se bave problemima inženjerstva tkiva, endodoncijom i implantologijom

Behaviour of Mg and Si substituted hydroxyapatites in model media

Thanks to its similarity with biological apatite found in vertebrate hard tissues, calcium hydroxyapatite is one of the most investigated materials in bone tissue engineering. Since biological apatite is not stoichiometric, ion substituted hydroxyapatites are in the focus of many studies as they more closely mimic the composition of natural bone. Although there are many investigations of the influence of foreign ions on the structure and physico-chemical properties of ionsubstituted hydroxyapatites, there is no much information on their behaviour in different media. In present study, magnesium - which plays a key role in bone metabolism and silicon - which is necessary for normal skeletal development, were used as ion substitutes. The behaviour of Mg and Si substituted hydroxyapatite in simulated body fluid and physiological solution was investigated by XRD, FTIR and SEM. Obtained results confirmed great potential of these substituted hydroxyapatites for biomedical applications

Biological properties of nitinol archwires coated with titanium nitride- copper films

Objectives: The main purpose of orthodontic treatment (OT) is to accomplish an optimal occlusal relationship in order to obtain adequate oral function and aesthetic appearance. Under optimal economic conditions, demand for OT reaches at least 35%, but in higher socioeconomic areas in US more than 50% of children are receiving orthodontic care. Acceptance of OT in Europe, like in western population and Scandinavian countries, is at similar levels. Very desirable mechanical characteristics, such as shape memory effect and superelasticity, expanded the use of nitinol (NiTi) archwires in orthodontics significantly. The complex conditions present in the oral cavity, including biofilm formation on the exposed surfaces, substantially alter the surface and structural properties of the NiTi archwires compromising the safety of OT. The necessity for developing novel material coating that would decrease Ni release and improve biological properties is of a great importance. Materials-Methods: Copper doped titanium nitride films (TiN-Cu) on the surface of NiTi archwires were obtained by combination of the cathodic arc evaporation and DC magnetron sputtering. The physicochemical characterization was performed using energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Ion release was assessed using inductively coupled plasma optical emission spectrometry (ICP-OES). The cytotoxicity of NiTi archwires, stainless steel (SS) archwires and TiN-Cu coated archwires was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT) test. In order to evaluate bacterial adhesion and biofilm formation, the following strains were used: Streptococcus mutans and Streptococcus mitis. Results: Physicochemical characterization revealed well-designed coatings with the presence of TiN phase with incorporated Cu. The release of Ni was the lowest regarding TiN-Cunanocoated archwires (p < 0.05) and increased in acidic conditions, while the release of Ti was constant. Contrary, the release of Cu was higher in neutral conditions and decreased during the observation time (p < 0.05). The cytotoxicity was the lowest in 28-day eluates of TiN-Cu-nanocoated archwires (p < 0.05). The coating inhibited the adhesion and growth of bacteria such as Streptococcus mitis and Streptococcus mutans (p < 0.05). Conclusion: Taking into account the results of cytotoxicity test and biofilm formation, TiN-Cunanocoated archwires may be considered as a good candidate for further clinical investigations.27th BaSS : November 9-11, Istanbul, Turkey, 2023