“…This may be attributed to Mg(OH) 2 and Mg 2+ as sites for the nucleation of apatite. The apatite plays significant roles in stimulating cell metabolism, bone regeneration, and chemical bonding between the biomaterial and bone tissues [ 50 , 51 ]. In a word, the results demonstrated that adding Mg(OH) 2 could effectively improve the apatite-forming ability and biomineralization of PLA scaffolds.…”
Polylactic acid (PLA) has attracted much attention in bone tissue engineering due to its good biocompatibility and processability, but it still faces problems such as a slow degradation rate, acidic degradation product, weak biomineralization ability, and poor cell response, which limits its wider application in developing bone scaffolds. In this study, Mg(OH)2 nanoparticles were employed as a versatile nanofiller for developing PLA/Mg(OH)2 composite bone scaffolds using fused deposition modeling (FDM) 3D printing technology, and its mechanical, degradation, and biological properties were evaluated. The mechanical tests revealed that a 5 wt% addition of Mg(OH)2 improved the tensile and compressive strengths of the PLA scaffold by 20.50% and 63.97%, respectively. The soaking experiment in phosphate buffered solution (PBS) revealed that the alkaline degradation products of Mg(OH)2 neutralized the acidic degradation products of PLA, thus accelerating the degradation of PLA. The weight loss rate of the PLA/20Mg(OH)2 scaffold (15.40%) was significantly higher than that of PLA (0.15%) on day 28. Meanwhile, the composite scaffolds showed long-term Mg2+ release for more than 28 days. The simulated body fluid (SBF) immersion experiment indicated that Mg(OH)2 promoted the deposition of apatite and improved the biomineralization of PLA scaffolds. The cell culture of bone marrow mesenchymal stem cells (BMSCs) indicated that adding 5 wt% Mg(OH)2 effectively improved cell responses, including adhesion, proliferation, and osteogenic differentiation, due to the release of Mg2+. This study suggests that Mg(OH)2 can simultaneously address various issues related to polymer scaffolds, including degradation, mechanical properties, and cell interaction, having promising applications in tissue engineering.
“…This may be attributed to Mg(OH) 2 and Mg 2+ as sites for the nucleation of apatite. The apatite plays significant roles in stimulating cell metabolism, bone regeneration, and chemical bonding between the biomaterial and bone tissues [ 50 , 51 ]. In a word, the results demonstrated that adding Mg(OH) 2 could effectively improve the apatite-forming ability and biomineralization of PLA scaffolds.…”
Polylactic acid (PLA) has attracted much attention in bone tissue engineering due to its good biocompatibility and processability, but it still faces problems such as a slow degradation rate, acidic degradation product, weak biomineralization ability, and poor cell response, which limits its wider application in developing bone scaffolds. In this study, Mg(OH)2 nanoparticles were employed as a versatile nanofiller for developing PLA/Mg(OH)2 composite bone scaffolds using fused deposition modeling (FDM) 3D printing technology, and its mechanical, degradation, and biological properties were evaluated. The mechanical tests revealed that a 5 wt% addition of Mg(OH)2 improved the tensile and compressive strengths of the PLA scaffold by 20.50% and 63.97%, respectively. The soaking experiment in phosphate buffered solution (PBS) revealed that the alkaline degradation products of Mg(OH)2 neutralized the acidic degradation products of PLA, thus accelerating the degradation of PLA. The weight loss rate of the PLA/20Mg(OH)2 scaffold (15.40%) was significantly higher than that of PLA (0.15%) on day 28. Meanwhile, the composite scaffolds showed long-term Mg2+ release for more than 28 days. The simulated body fluid (SBF) immersion experiment indicated that Mg(OH)2 promoted the deposition of apatite and improved the biomineralization of PLA scaffolds. The cell culture of bone marrow mesenchymal stem cells (BMSCs) indicated that adding 5 wt% Mg(OH)2 effectively improved cell responses, including adhesion, proliferation, and osteogenic differentiation, due to the release of Mg2+. This study suggests that Mg(OH)2 can simultaneously address various issues related to polymer scaffolds, including degradation, mechanical properties, and cell interaction, having promising applications in tissue engineering.
“…Hence H1 composite showed better bioactivity than neat PLA. 47,48 Figure 11.SEM micrographs of H0 (a), (b) and H1 (c), (d), before and after immersion in SBF after 14 days.…”
In this study, biocomposites as feedstock material for 3D printing were produced by poly (lactic acid) (PLA) as a polymer matrix and Hydroxyapatite (HAP) as reinforcing filler for potential use in biomedical applications. Biocomposites filament from PLA and different HAP content varying from 1–10 wt% were prepared from extrusion and then injection moulding process. The impact of HAP loading on the properties of biocomposites was investigated for crystallinity, density, hardness, tensile, impact, flexural, melt flow index (MFI), thermal properties and biomineralization studies. The formation of PLA/HAP biocomposites was confirmed by fourier transform infrared spectroscopy (FTIR). The hydrophilicity of the biocomposites was studied by contact angle analysis. Dispersion of HAP into PLA matrix was confirmed by scanning electron microscopy (SEM) and optical microscopy. The HAP addition increased the density of the composites. From mechanical analysis PLA/HAP composites containing 1–5 wt% showed an increase in tensile modulus. The Shore D hardness of the composites increased with increase in wt% of HAP content. The maximum hardness was achieved for 10 wt% of HAP content i.e., 87 ± 0.1, which is about 6.1% more than neat PLA. The MFI increased with rise in HAP content that gives a positive opinion of reinforcing PLA composites without deteriorating the processability. The hydrophilicity of the biocomposites was slightly increased after the addition of HAP. From thermal analysis it was concluded that the thermal stability of the biocomposites increased when compared with neat PLA. From the Biomineralization studies formation of apatite layer on PLA composites was confirmed by SEM analysis.
“…Other evidence for the promotion of apoptosis by NGAL is the activation of caspase 3, 8 and 9 in nasopharyngeal carcinoma (NPC) [113]. Nevertheless, regarding AAA, NGAL expression also predisposes to the formation of NGAL/MMP-9 complexes and consequently protects MMP-9 from proteolytic degradation causing the degradation of the ECM components of the aorta [84].…”
A disturbance of the structure of the aortic wall results in the formation of aortic aneurysm, which is characterized by a significant bulge on the vessel surface that may have consequences, such as distention and finally rupture. Abdominal aortic aneurysm (AAA) is a major pathological condition because it affects approximately 8% of elderly men and 1.5% of elderly women. The pathogenesis of AAA involves multiple interlocking mechanisms, including inflammation, immune cell activation, protein degradation and cellular malalignments. The expression of inflammatory factors, such as cytokines and chemokines, induce the infiltration of inflammatory cells into the wall of the aorta, including macrophages, natural killer cells (NK cells) and T and B lymphocytes. Protein degradation occurs with a high expression not only of matrix metalloproteinases (MMPs) but also of neutrophil gelatinase-associated lipocalin (NGAL), interferon gamma (IFN-γ) and chymases. The loss of extracellular matrix (ECM) due to cell apoptosis and phenotype switching reduces tissue density and may contribute to AAA. It is important to consider the key mechanisms of initiating and promoting AAA to achieve better preventative and therapeutic outcomes.
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