Bioactive Ceramic Materials Research Articles

Silver-doped glass-ceramic scaffolds with antibacterial and bioactive properties for bone substitution

The preparation of scaffolds that are both macroporous and mechanically strong is a significant challenge in the development of bioactive ceramic materials for bone substitution. Furthermore, the introduction of beneficial extra-functionalities such as bacterial inhibition is highly appealing but adds complexity to implant design and production. In this study, we aimed to fabricate highly porous, bioactive and antibacterial glass-ceramic scaffolds with interconnected macropores through the foam replica method. The scaffolds were sintered at two different temperatures (620 and 850 °C), yielding glassy or partially crystallized materials, respectively. The scaffold produced at higher temperature was found to be highly porous (>75 vol%), mechanically stronger and able to induce hydroxyapatite formation after three days of soaking in SBF (in vitro bioactivity). In order to confer antibacterial activity, silver (Ag) ions were introduced onto the scaffold surface through ion exchange in an aqueous solution. Compositional analysis confirmed the successful doping of the scaffold surface with silver, which was continuously released in SBF for at least 28 days, as revealed by ICP-MS. Finally, the antibacterial action of the Ag-doped scaffold was confirmed towards Staphylococcus epidermidis. Overall, the results reported in this work show the potential of foam-like Ag-doped bioactive glass-ceramic scaffolds to be used in applications requiring bone substitution and antibacterial properties.

Influence of Hydroxyapatite Particle Size on the Flowability of PLA/HA Filament

Advanced bioactive ceramic materials, Hydroxyapatite (HA) and Polylactic Acid (PLA) are common in bone regeneration implants. As demand for customised implant products increases, research increasingly focuses on developing composite filament manufacturing technology. However, creating PLA/HA composite filament faces challenges, including clumping HA particles and uneven flowability. The brittleness of the filament properties makes it unsuitable for Fused Deposition Modelling (FDM) printing, causing inconsistent extrusion and reduced filament strength. The purpose of this study is to compare the effectiveness of microHAs (m-HAs) and nanoHAs (n-HAs) in the production of filament composite fibers, based on the flowability assessment. The particle size of the micro-HA was reduced to nano by a ball mill process using 4 mL ethanol and the ball-powder ratio of 5:1, which was verified by the particle size analyzer. The feedstock comprises 79.5 wt.% PLA, 19.5 wt.% HA and 1 wt.% impact modifier (IMK) was mixed and rheological tested (130 ℃ to 150 ℃, shear rate: 20-1000 s-1) to achieve pseudoplastic behaviour (n<1). The rheological tests showed that both feedstocks exhibited pseudoplastic behaviour (n<1) across all temperatures studied. The properties of the feedstock were observed by scanning electron microscopy (SEM), and tensile tests evaluated the filament strength. The investigation found that nano-sized HA filament has 24% higher strength than micro-sized PLA/HA filament.

Effects of Sr and Mg doping on elastic, mechanical, and optical properties of hydroxyapatite: A first-principles study

Hydroxyapatite (HAp), with the chemical formula Ca10(PO4)6(OH)2, is a bioactive ceramic material typically used in the treatment of bone defects owing to the excellent biocompatibility and the ability to bond with bone tissues. Mechanical properties of HAp have drawn pronounced attention because of the crucial roles in the medical applications. Based on density functional theory (DFT), this work reports the structural, formation energy, mechanical, Vickers hardness, electronic properties, and optical properties of hydroxyapatite (HAp), strontium-substituted HAp (Sr-HAp), and magnesium-substituted HAp (Mg-HAp). The results reveal that the Sr2+ and Mg2+ ions mainly replace the Ca2+ ion at the Ca-1 site in HAp. Resistance to hydrostatic compression followed the order Mg-HAp > HAp > Sr-HAp. Sr-HAp has the capability to enhance thermal shock resistance and lattice thermal conductivity. In addition, the electronic properties of HAp change upon substitutional Sr2+ and Mg2+ doping. In comparison with pristine HAp, the energy gap of Sr-doped HAp relatively increases, whereas that of Mg-doped HAp decreases. Nevertheless, both Sr-HAp and Mg-HAp remain insulators. Intriguingly, Sr-HAp possesses the improved hardness by 11.31 % owing to the hybridization of the Sr (4p) and O (2p) states, which contributed to its high shear modulus and high hardness. Beyond that, we further investigate their optical properties. The presence of Mg states at approximately 10 eV in the conduction band leads to enhanced absorption within the 14 – 20 eV for Mg-doped HAp. Similarly, the presence of a deep Sr(4p) level in Sr-HAp amplifies absorption within the 20–25 eV range. These findings have raised a potential avenue for selectively boosting the optical absorption of HAp, thus improving its photocatalytic properties.

Morphological aspects and distribution of granules composed of deproteinized bovine bone or human dentin into a putty mixture: an in vitro study

ObjectiveThe main aim of this study was to evaluate the morphological aspects and distribution of granules composed of deproteinized bovine bone mineral (DBBM) and human dentin-derived bone graft (HDBG) into a putty consistency mixture.Materials and methodsDBBM or HDBG were mixed with an alginate-based hydrogel at two different granule/hydrogel ratio (1:1 and 1:3) and divided into four test groups while two control groups were composed of DBBM or HDBG free of hydrogel. Groups of specimens were cross-sectioned for morphological evaluation by scanning electron microscopy (SEM) at backscattered electrons mode. Details on the dimensions and pores’ size of DBBM and HDBG were evaluated after mixing different amounts of particles and alginate-based hydrogels.ResultsMicroscopic analyses revealed a size of DBBM granules ranging from 750 up to 1600 μm while HDBG particles showed particle size ranging from 375 up to 1500 μm. No statistical differences were identified regarding the size of granules (p > 0.5). The mean values of pores’ size of DBBM particles were noticed at around 400 μm while HDBG particles revealed micro-scale pores of around 1–3 μm promoted by the dentin tubules (p < 0.05). The lowest distance between particles was at 125 μm for HDBG and 250 μm for DBBM when the particle content was increased. On decreasing the particles’ content, the distance between particles was larger for DBBM (~ 1000 μm) and HDBG (~ 1100 μm). In fact, statistically significant differences were found when the content of granules increased (p < 0.05).ConclusionsThe increased content of bioactive ceramic granules in a putty consistency mixture with hydrogel decreased the space among granules that can promote a high ceramic density and stimulate the bone growth over the healing process. Macro-scale pores on bovine bone mineral granules stimulate the formation of blood vessels and cell migration while the micro-scale pores of dentin-derived granules are proper for the adsorption of proteins and growth of osteogenic cells on the bone healing process.Clinical significanceA high amount of bioactive ceramic granules should be considered when mixing with hydrogels as a putty material since that result in small spaces among granules maintaining the bone volume over the bone healing process. Deproteinized bovine bone mineral granules have macro-scale pores providing an enhanced angiogenesis while dentin-derived granules possess only micro-scale pores for the adsorption of proteins and proliferation of osteogenic cells on the bone healing process. Further studies should evaluate the combination of different bioactive ceramic materials for enhanced bone healing.

New bone substitute based on nanodispersed calcium ceramics

The article is devoted to developing a synthetic material for bone tissue restoration. The synthesis of bioactive nanostructured ceramic materials was optimized by selecting temperature regimes, parameters of precursors, etc. A new nanostructured bioactive inorganic material - a complex of nanostructured bioactive ceramics with the most effective osteotropic properties was created. It contains calcium phosphate phases, bioactive glasses, and sitalls, including those doped with bioactive elements that give the material unique biological properties, particularly - the prevention and suppression of concomitant diseases. The new material was obtained using gallium and germanium doping of calcium nanodisperse ceramics. The material has been tested experimentally on animals

Review on vat photopolymerization additive manufacturing of bioactive ceramic bone scaffolds.

Bone defects frequently occur in clinical settings due to trauma, disease, tumors, and other causes. The clinical use of autologous bones and allograft bone, however, has several limitations, such as limited sources, donor site morbidity, and immunological rejection. Nevertheless, there is newfound hope for regenerating and repairing bone defects through the development and integration of bone tissue engineering scaffold and additive manufacturing (AM) technology, also known as 3D printing. In particular, vat photopolymerization (VPP)-AM of bioactive ceramic bone scaffolds has garnered significant interest from interdisciplinary researchers in recent years. On the one hand, VPP-AM demonstrates clear advantages in printing accuracy and speed compared to other AM and non-AM technologies. On the other hand, bioactive ceramic materials exhibit superior bioactivity, biodegradability, and mechanical properties compared to metals, polymers, and bioinert ceramics, making them one of the most promising biomaterials for developing bone scaffolds. This paper reviews the research progress of VPP-AM of bioactive ceramic bone scaffolds, covering the process principles of various VPP-AM technologies, the performance requirements and preparation process of VPP ceramic slurry, the VPP process of bioactive ceramic bone scaffolds, and the research progress on different material types of VPP bioactive ceramic scaffolds. Firstly, we provide a brief introduction to the process principles and medical applications of various VPP technologies. Secondly, we explore the composition of the VPP ceramic slurry system, discussing the function of various components and their effects on printing quality. Thirdly, we delve into the performance requirements of bone scaffolds and summarize the research progress of VPP bioactive ceramic bone scaffolds of various material types including hydroxyapatite (HA), tricalcium phosphate (TCP), bioglass (BG), etc.; Finally, we discuss the challenges currently faced by VPP-AM bioactive ceramic bone scaffolds and propose possible development directions for the future.

COMPARING THE EFFECTS OF TWO WET PRECIPITATION METHODS ON THE YIELD OF CHICKEN EGGSHELL-DERIVED HYDROXYAPATITE

Research into better and more improved biomaterials is at the forefront of modern biomedicine. A calcium phosphate compound known as Hydroxyapatite is one of the most bioactive and biocompatible osteoconductive ceramic materials currently known to man. It occurs naturally in the bones, teeth, and shells of some animals and the leaves, and stalks of some plants. It can also be synthesized artificially. Eggshells are very prominent sources of Hydroxyapatite and currently constitute waste, and environmental pollution due to ineffective, wrong, and incorrect disposal. In this research, two modified variants of the wet chemical precipitation method were used to produce hydroxyapatite from chicken eggshells gotten from the same source. The obtained samples were then characterized using XRD and SEM. The results of the characterization were analyzed to determine the most efficient, cost-effective, and less tedious method of production. It was discovered that although the orthophosphoric acid-based wet precipitation method was more efficient in producing phase pure hydroxyapatite, the nitric acid-based wet chemical precipitation method was found to be better than the orthophosphoric-based wet chemical precipitation method in terms of particle size, agglomeration, elemental analysis, and other observed properties.

In Ukrainian

Bone tumor diseases are one of the main problems in modern clinical practice. After surgery, some of the tumor cells capable of proliferation may remain, leading to tumor recurrence. In addition, surgical ablation of bone tumors creates bone tissue defects. Therefore, the problem of manufacturing specific biomaterials with a dual function of treating bone tumors and regeneration of bone defects has become a priority. The use of methods of targeted delivery and local controlled release of drugs contributes to the creation of the desired therapeutic concentration of drugs in the disease focus and increases their bioavailability. In recent years, promising samples capable of effective controlled release have been developed in which cisplatin, doxorubicin and gemcitabine have been used as model chemotherapeutic drugs. These approaches have been promising and have shown the potential to destroy residual tumor cells, however, they may become resistant to such drugs, which leads to treatment failure. The main purpose of the review is to summarize the latest world experience in the synthesis, research and use of composites based on bioactive ceramic materials and modern antitumor drugs as promising implants, embodying a new generation of complex remedies for targeted delivery with osteoconductive and antitumor properties, prolonged action, for local application. Examples are given of bioglass application with cytotoxic / cytostatic components, as well as results of development of the newest directions of antitumor therapy of bones, in which acquisition of resistance of tumor cells is not observed. The antitumor functions of such multifunctional samples are performed, for example, by chemotherapy, photothermal therapy, magnetic hyperthermia, and photodynamic therapy. These data are of scientific, practical and methodical interest.

Osteoinductive and antimicrobial mechanisms of graphene-based materials for enhancing bone tissue engineering.

Graphene-based materials (GMs) have great application prospects in bone tissue engineering due to their osteoinductive ability and antimicrobial activity. GMs induce osteogenic differentiation through several mechanisms and pathways in bone tissue engineering. First of all, the surface and high hardness of the porous folds of graphene or graphene oxide (GO) can generate mechanical stimulation to initiate a cascade of reactions that promote osteogenic differentiation without any chemical inducers. In addition, change of the extracellular matrix (ECM), regulation of macrophage polarization, the oncostatin M (OSM) signaling pathway, the MAPK signaling pathway, the BMP signaling pathway, the Wnt/β-catenin signaling pathway, and other pathways are involved in GMs' regulation of osteogenesis. In bone tissue engineering, GMs prevent the formation of microbial biofilms mainly through preventing microbial adhesion and killing them. The former is mainly achieved by reducing surface free energy (SFE) and increasing hydrophobicity. The latter mainly includes oxidative stress and photothermal/photodynamic effects. Graphene and its derivatives (GDs) are mainly combined with bioactive ceramic materials, metal materials and macromolecular polymers to play an antimicrobial effect in bone tissue engineering. Concentration, number of layers, and type of GDs often affect the antimicrobial activity of GMs. In this paper, we reviewed relevant osteoinductive and antimicrobial mechanisms of GMs and their applications in bone tissue engineering.

Enhanced Bioactivity of Micropatterned Hydroxyapatite Embedded Poly(L-lactic) Acid for a Load-Bearing Implant.

Poly(L-lactic) acid (PLLA) is among the most promising polymers for bone fixation, repair, and tissue engineering due to its biodegradability and relatively good mechanical strength. Despite these beneficial characteristics, its poor bioactivity often requires incorporation of bioactive ceramic materials. A bioresorbable composite made of PLLA and hydroxyapatite (HA) may improve biocompatibility but typically causes deterioration in mechanical properties, and bioactive coatings inevitably carry a risk of coating delamination. Therefore, in this study, we embedded micropatterned HA on the surface of PLLA to improve bioactivity while eliminating the risk of HA delamination. An HA pattern was successfully embedded in a PLLA matrix without degeneration of the matrix’s mechanical properties, thanks to a transfer technique involving conversion of Mg to HA. Furthermore, patterned HA/PLLA’s biological response outperformed that of pure PLLA. These results confirm patterned HA/PLLA as a candidate for wide acceptance in biodegradable load-bearing implant applications.

Fabrication of a hydroxyapatite-PDMS microfluidic chip for bone-related cell culture and drug screening

Bone is an important part of the human body structure and plays a vital role in human health. A microfluidic chip that can simulate the structure and function of bone will provide a platform for bone-related biomedical research. Hydroxyapatite (HA), a bioactive ceramic material, has a similar structure and composition to bone mineralization products. In this study, we used HA as a microfluidic chip component to provide a highly bionic bone environment. HA substrates with different microchannel structures were printed by using ceramic stereolithography (SLA) technology, and the minimum trench width was 50 μm. The HA substrate with microchannels was sealed by a thin polydimethylsiloxane (PDMS) layer to make a HA-PDMS microfluidic chip. Cell culture experiments demonstrated that compared with PDMS, HA was more conducive to the proliferation and osteogenic differentiation of the human foetal osteoblast cell line (hFOB). In addition, the concentration gradient of the model drug doxorubicin hydrochloride (DOX) was successfully generated on a Christmas tree structure HA-PDMS chip, and the half maximal inhibitory concentration (IC50) of DOX was determined. The findings of this study indicate that the HA-PDMS microfluidic chip has great potential in the field of high-throughput bone-related drug screening and bone-related research.

Bioscaffolds in Periodontal Regeneration

Background: Tissue engineering is a highly evolving field in periodontology which incorporates the use of cells, signalling molecules and scaffolds thereby creating a three dimensional microenvironment facilitating cellular growth and function for restoration of lost tissues due to periodontal disease. This review discusses the various types, ideal characteristics, properties and applications of potential scaffolds that can be used in periodontal regeneration with the help of principles of tissue engineering. Methods: Research work pertaining to bioscaffolds for periodontal regeneration were selected using key words in major databases and internet sources. Results: Studies related to various features of scaffold and its inherent properties were searched and analysed. Data were organized considering the sources of its origin and salient features of these inert matrices. Specific probe into the techniques and medium used for developing scaffolds were cited. Further, bioactive ceramic materials which are involved in stimulating cell proliferation, and bone tissue regeneration, which may also facilitate periodontal regeneration were mentioned. Likewise, few data linked to different types of biodegradable synthetic scaffolds and its advantages were considered. The progress of science in various fabrication techniques and newer advances using modern technology such as tissue engineering approaches, 3D printing and physical &amp; chemical methods to enhance the physical properties are being used to make them more versatile for the application in the field of biomedical science. Conclusion: In lieu of the available literature search and vast progress in material science, scaffolds construction for cellular regeneration requires wide exploration. Furthermore, when these scaffolds are placed at a particular site, it should be able to restore lost periodontal tissue. Also, the newer innovative technologies like the 3D version of biomimicking, nano/micro-based scaffolds displays potential for further extensive research and complete regeneration of periodontal tissues.

Inhibitory Effect of 5-Aminoimidazole-4-Carbohydrazonamides Derivatives Against Candida spp. Biofilm on Nanohydroxyapatite Substrate.

Candida can adhere and form biofilm on biomaterials commonly used in medical devices which is a key attribute that enhances its ability to cause infections in humans. Furthermore, biomaterial-related infections represent a major therapeutic challenge since Candida biofilms are implicated in antifungal therapies failure. The goals of the present work were to investigate the effect of three 5-aminoimidazole-4-carbohydrazonamides, namely (Z)-5-amino-1-methyl-N'-aryl-1H-imidazole-4-carbohydrazonamides [aryl = phenyl (1a), 4-fluorophenyl (1b), 3-fluorophenyl (1c)], on Candida albicans and Candida krusei biofilm on nanohydroxyapatite substrate, a well-known bioactive ceramic material. To address these goals, both quantitative methods (by cultivable cell numbers) and qualitative evaluation (by scanning electron microscopy) were used. Compounds cytocompatibility towards osteoblast-like cells was also evaluated after 24h of exposure, through resazurin assay. The three tested compounds displayed a strong inhibitory effect on biofilm development of both Candida species as potent in vitro activity against C. albicans sessile cells. Regarding cytocompatibility, a concentration-dependent effect was observed. Together, these findings indicated that the potent activity of imidazole derivatives on Candida spp. biofilms on nanohydroxyapatite substrate, in particular compound 1c, is worth further investigating.

Bioactive composites for bone regeneration

Bone, the organ that separates vertebrates from other living beings, is a complex tissue responsible of mobility, body stability, organ protection, and metabolic activities such as ion storage. Ceramic materials are appropriate candidates to be used in the fabrication of scaffolds for bone healing. Biocompatible ceramic materials may also be created to deliver biologically active substances aimed at maintaining, repairing, restoring, or boosting the function of tissues and organs in the organism. Glass-ceramic materials furnish flexible properties appropriate for some particular applications. Because of the controlled devitrification and the evolution of variable dimensions of crystalline and glassy phases, glass-ceramics considerably overcome the lacunae found in glasses. A wide range of bioactive glass compositions had been developed since the early 1970s to make them appropriate for many clinical applications. Many bioactive ceramic composite materials attach to living bone through an apatite layer, which is developed on their surfaces in the living body. This paper reviews the most used bioactive ceramics for bone tissue regeneration, with specific accentuation on the material characteristics.

Investigations for mechanical properties of PLA-HAp-CS based functional prototypes

Abstract This paper reports the investigations on blend of biocompatible and biodegradable polymer, poly lactic acid (PLA) reinforced with another biocompatible and bioactive polymer chitosan (CS) and ceramic material; hydroxyapatite (HAp) from material processing view point. The blend has been selected based upon melt flow index (MFI), flowability, thermal stability and mechanical testing. After ascertaining proportion/composition of PLA-HAp-CS on twin-screw extruder (TSE) feedstock filaments for fused deposition modelling (FDM) have been prepared. The fabricated feedstock filaments were used on FDM for printing of biomedical scaffolds (with input parameters as: layer thickness, deposition angle and infill density). The tensile and flexural tests of functional prototypes were performed on the universal tensile tester (UTT). Finally combined optimization was performed on tensile and flexural samples to determine the best setting of open-source FDM for printing of biomedical scaffolds.

Lithium-zirconium silicate glass-ceramics for restorative dentistry: Physicochemical analysis and biological response in contact with human osteoblast

The main aim of this study was to evaluate the physicochemical and biological behavior of (LZS) lithium-zirconium and (LZSA) lithium-zirconium-alumina silicate glass-ceramics. LZS and LZSA silicate glass-ceramics were produced from commercial raw materials by melting (1550 °C/2 h) followed by water-cooling casting. The obtained glass frits were milled by a two-step process (dry and wet milling) up to achieve 5–10 μm particles. The milled powder was uniaxially pressed (50 MPa) and later fired at 900 °C/2 h (LZS) and at 850 °C/2 h (LZSA). Specimens were characterized by physical, chemical, thermal, and cell culture assays. Crystalline phases such ZrSiO4 and residual quartz and lithium metasilicate (Li2SiO3) was found in the LZS group microstructure while LZSA showed a mixture of ZrSiO4 and β-spodumene (LiAlSi2O6). Materials showed different thermal behavior and mechanical properties. LZS silicate glass ceramics revealed higher fracture toughness and Young's modulus values than those recorded for LZSA silicate glass-ceramics. A higher percentage of osteoblast cell proliferation and mineralization was detected on LZS surfaces when compared to LZSA surfaces. The chemical composition, microstructure, thermal behavior, and mechanical strength of LZS and LZSA silicate glass-ceramic can be adjusted for manufacturing of prosthetic structures for oral rehabilitation. Also, the interaction of glass-ceramics with human cells and tissues can be enhanced by increasing the content of bioactive ceramic materials such as silica or by adding additional bioactive compounds such as beta-tricalcium phosphate.

Morphology and mechanical properties fabricated from Ti, Nb and HA by powder metallurgy method

Hydroxyapatite (HA) is a bioactive ceramic material with poor mechanical properties which hinders its application in bone implant. However, HA has a similar structure to bone and can promote the growth of natural tissues. Combining the low modulus β-type Titanium (Ti) based alloy (e.g:Ti-40Nb) which has excellent mechanical properties and non-toxic composition with HA is considered as a good candidate to expand its biomedical applications. In this current work, Ti, Ti-40Nb and Ti-40Nb-15HA (wt.%) was compacted under 500 MPa using powder metallurgy process. The mixtures were performed by high energy milling and sintering in a tube furnace with temperature of 1200°C/2 h under argon flow. The aim of this research is to investigate the morphology and the mechanical properties of metal alloys. Images obtained by SEM show a homogeneous morphology of voids with smooth surface for Ti and Ti-40Nb while Ti-40Nb-15HA show the presence of pores located at grain boundary and exhibit rough surface appearance. Ti-40Nb-15HA alloy was found to give a favourable compression strength and low density at 171.93 MPa and 5.086 g/cm3, respectively. Thus, considering its mechanical properties, Ti-40Nb-15HA was found ideal for orthopaedic implant materials as it has properties closed to human bone.

Bioactivity of novel functionally structured titanium-ceramic composites in contact with human osteoblasts.

The aim of this study was to analyze the osteogenic cell behavior on the surface of novel functionally graded titanium-based composites containing bioactive ceramics. Titanium grade V discs (8 × 3 mm) embedding gradual content of hydroxyapatite (TiAlV-HA) or beta-tricalcium phosphate (TiAlV-βTCP) were produced by hot-pressing technique. Titanium-ceramic composite discs and Ti grade V (control group) were placed in contact with human osteoblast culture assays. The morphology and adhesion of osteoblasts were inspected by field emission guns scanning electron microscopy (FEGSEM) while cell viability was assessed by fluorometric method. Alkaline phosphatase (ALP) activity and fluorescent microscopic analyses were used to evaluate mineralization on the test and control discs. FEGSEM images showed cells adhered to Ti6Al4V-ceramic and Ti6Al4V surfaces over a period of 24 h, and therefore, an intense proliferation of osteoblasts and spreading cells was noticed for 7 days. Cell viability increased with time on all the surfaces although TiAlV-βTCP revealed significant higher percentage of cell viability than that recorded for TiAlV-HA (p < 0.01). TiAlV-βTCP also showed the highest hydrophilic character. ALP levels increased on the Ti6Al4V-ceramic surfaces when compared to the control group. Also, a qualitative analysis of mineralization evidenced an increase in mineral content on TiAlV-HA or TiAlV-βTCP groups. Novel functionally graded composites based on Ti grade V and hydroxyapatite or βTCP showed a higher bioactivity in presence of osteoblasts than that recorded on Ti grade V. Also, such functionally graded materials can prevent risks of failures by detachment of bioactive ceramic materials during implant placement. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1923-1931, 2018.

3D printing technology applied in orthopaedics

3D is an important technology occurs in 1980s, which has been about more than 30 years since the first 3D machine was developed. Currently, it develops rapidly and its application scope has been greatly expanded. Its most prominent features are the and the diversification of printing ink. The can make it possible to tailor the biological materials for each patient, and the diversity of printing can make the technology meeting different clinical needs. 3D can be divided into four aspects: 1) the collection and formation of image of object; 2) the treatment and the transformation of the image information; 3) based on the data formatted; 4) the post-treatment and performance evaluating of the object. At present, the common methods related to orthopaedics include: 1) stereolithography appearance; 2) selective laser sintering; 3) fused deposition modeling; 4) laminated object manufacturing; 5) the direct metal melting technology (selective laser melting or electron beam melting); 6) the ink jet technology. A variety of materials have been used in 3D printers, including the natural medical materials like collagen and chitosan, the synthetic polymers like polylactic acid, polyglycolic acid and peek, the bioactive ceramic materials like hydroxyapatite, the medical metal materials like titanium. The 3D printed material are mainly used in the following seven aspects in orthopaedics: 1) the preoperative planning, such as the of the lesion and resection model; 2) operation navigation make the surgery procedure more accurate; 3) making the customized prosthesis and implant; 4) implanting the external fixation; 5) the development of new surgical instruments meets the special needs of patients; 6) making the personalized tissue engineering scaffold used in regenerative medicine; 7) the development of drug and its release study.

Bivalent cationic ions doped bioactive glasses: the influence of magnesium, zinc, strontium and copper on the physical and biological properties

Bioactive glass and glass ceramic materials are widely used as substitutes for bone augmentation and restoration, in orthopaedic, dental and maxillofacial surgery and in the tissue engineering field. Indeed, these materials are bioactive, biocompatible, mechanically stable, biodegradable and favour osteointegration, being able to promote bone tissue formation at their surface and to bond to surrounding living tissues when implanted in the human body. It has been demonstrated that bioglass (BG) ionic dissolution products (e.g. Si, Ca, P and Na) are able to induce and stimulate the expressions of genes related to the osteoblastic differentiation and bone formation, to stimulate angiogenesis in vitro and in vivo, as well as to play possible antibacterial and anti-inflammatory actions. Thus, it is possible to tailor BGs properties properly formulating their chemical composition and adding selected ions with specific functional and biological role. In this perspective, Hench proposed a new generation of genetically designed glasses, on the basis of their ability to activate specific genes involved in in situ tissue regeneration, by doping silicate and phosphate glasses with several active ions, particularly metallic ions with therapeutic effects. In this framework, the present review is aimed to provide an overview about the effect of selected cationic substitutions (i.e. magnesium, zinc, strontium and copper), incorporated within the bioglasses structure, on the physical and biological properties of these materials, since the comprehension of the influence of the most employed metallic ions has to be considered pivotal to address the formulation of more promising and performing glasses.