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BACKGROUND:At present,the traditional powder sintering method is easy to introduce impurities in the process of preparing porous titanium,and the manufacturing of porous titanium still faces two major problems:impurity pollution and difficult control of the material forming process. OBJECTIVE:To prepare pure porous titanium with certain porosity,and analyze the microstructure evolution and properties of the porous titanium. METHODS:Porous titanium was prepared at a low energy density by selective laser melting technology.The parameter range of porous titanium with large porosity was obtained by measuring the porosity of the formed specimen,and the evolution of the microstructure and mechanical properties of the specimen in the range were analyzed. RESULTS AND CONCLUSION:(1)With the increase in energy density,the porosity of the porous titanium specimen decreased gradually.When the energy density was between 10.61 and 27.78 J/mm3,porous titanium with a porosity of 11.23%-33.67%could be formed.When the energy density was between 27.78-37.88 J/mm3,the forming parts were relatively dense.(2)The phase composition of porous titanium formed was mainly α titanium.With the increase in energy density,the porosity gradually decreased,and the pore morphology changed from irregularly connected pores to closed nearly spherical pores.The powder particles changed from a slightly sintered neck to a continuous fuse.The CT scan results revealed that there were a large number of connected pores in the forming specimen with a large specific surface area and the pore radius was roughly distributed between 2-6 μm at the energy density of 10.61 J/mm3.Simultaneously,porous titanium with compressive strength of 188-1 000 MPa could be obtained at the energy density of 10.61-27.78 J/mm3,which could meet the requirements of biomedical applications.(3)These results have confirmed that the selective laser melting technology can overcome the problems of impurity pollution and long manufacturing cycle caused by the traditional preparation process,and provide an effective solution for the preparation of porous titanium with excellent mechanical properties.
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BACKGROUND:Medium-and large-diameter polytetrafluoroethylene artificial blood vessels have been widely used in clinical practice.However,most of the products were imported from other countries.Small-diameter porous polytetrafluoroethylene vessels are easy to form thrombosis and intimal hyperplasia,resulting in an extremely low long-term patency rate,which is difficult to fulfill clinical requirements. OBJECTIVE:To review and summarize the research progress of polytetrafluoroethylene in the field of artificial blood vessels,which can provide a reference for the functional modification of small-diameter polytetrafluoroethylene artificial blood vessels and the improvement of their long-term patency rate. METHODS:The relevant articles published from October 2022 to March 2023 in CNKI,Web of Science,Wiley Online Library,SpringerLink,Science Direct and IOP Science databases were searched by the first author.The search terms in Chinese were"porous polytetrafluoroethylene,vascular graft,electrospinning,medical application,functional modification".The search terms in English were"ePTFE,porous polytetrafluoroethylene,vascular graft,electrospinning,medical application,functional modification".All the articles about the preparation and modification of polytetrafluoroethylene artificial blood vessels were retrieved. RESULTS AND CONCLUSION:The preparation and functional modification of porous polytetrafluoroethylene artificial blood vessels were still research hotspots and difficult problems.From the research progress in and outside China in recent years,the preparation of porous polytetrafluoroethylene artificial blood vessels mainly adopted the rapid thermal stretching method,but the preparation of polytetrafluoroethylene artificial blood vessels by electrospinning was a promising new method.By analyzing and summarizing different functional modification methods,it was found that the long-term patency rate of porous polytetrafluoroethylene artificial blood vessels had been improved.However,the functional modification of small-diameter polytetrafluoroethylene artificial blood vessels still needed further exploration and optimization.
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BACKGROUND:Due to the sudden release and the rapid removal by proteases,platelet-rich plasma hydrogel leads to shorter residence times of growth factors at the wound site.In recent years,researchers have focused on the use of hydrogels to encapsulate platelet-rich plasma in order to improve the deficiency of platelet-rich plasma hydrogels. OBJECTIVE:To prepare self-assembled polypeptide-platelet-rich plasma hydrogel and to explore its effects on the release of bioactive factors of platelet-rich plasma. METHODS:The self-assembled polypeptide was synthesized by the solid-phase synthesis method,and the solution was prepared by D-PBS.Hydrogels were prepared by mixing different volumes of polypeptide solutions with platelet-rich plasma and calcium chloride/thrombin solutions,so that the final mass fraction of polypeptides in the system was 0.1%,0.3%,and 0.5%,respectively.The hydrogel state was observed,and the release of growth factors in platelet-rich plasma was detected in vitro.The polypeptide self-assembly was stimulated by mixing 1%polypeptide solution with 1%human serum albumin solution,so that the final mass fraction of the polypeptide was 0.1%,0.3%,and 0.5%,respectively.The flow state of the liquid was observed,and the rheological mechanical properties of the self-assembled polypeptide were tested.The microstructure of polypeptide(mass fraction of 0.1%and 0.001%)-human serum albumin solution was observed by scanning electron microscope and transmission electron microscope. RESULTS AND CONCLUSION:(1)Hydrogels could be formed between different volumes of polypeptide solution and platelet-rich plasma.Compared with platelet-rich plasma hydrogels,0.1%and 0.3%polypeptide-platelet-rich plasma hydrogels could alleviate the sudden release of epidermal growth factor and vascular endothelial growth factor,and extend the release time to 48 hours.(2)After the addition of human serum albumin,the 0.1%polypeptide group still exhibited a flowing liquid,the 0.3%polypeptide group was semi-liquid,and the 0.5%polypeptide group stimulated self-assembly to form hydrogel.It was determined that human serum albumin in platelet-rich plasma could stimulate the self-assembly of polypeptides.With the increase of the mass fraction of the polypeptide,the higher the storage modulus of the self-assembled polypeptide,the easier it was to form glue.(3)Transmission electron microscopy exhibited that the polypeptide nanofibers were short and disordered before the addition of human serum albumin.After the addition of human serum albumin,the polypeptide nanofibers became significantly longer and cross-linked into bundles,forming a dense fiber network structure.Under a scanning electron microscope,the polypeptides displayed a disordered lamellar structure before adding human serum albumin.After the addition of human serum albumin,the polypeptides self-assembled into cross-linked and densely arranged porous structures.(4)In conclusion,the novel polypeptide can self-assemble triggered by platelet-rich plasma and the self-assembly effect can be accurately adjusted according to the ratio of human serum albumin to polypeptide.This polypeptide has a sustained release effect on the growth factors of platelet-rich plasma,which can be used as a new biomaterial for tissue repair.
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BACKGROUND:Previous research by the research team found that domestically produced porous tantalum is beneficial for early adhesion and proliferation of MG63 cells,and can be used as a scaffold material for bone tissue engineering. OBJECTIVE:To investigate the effect of domestic porous tantalum modified by osteogenic induction factor slow-release system on the adhesion,proliferation,and differentiation of MG63 cells. METHODS:Osteogenic induction factor slow-release system was constructed by adding 15%volume fraction of osteogenic factor solution to poly(lactic-co-glycolic-acid)gel.The passage 3 MG63 cells were inoculated on a porous tantalum surface(control group),porous tantalum surface coated with poly(lactic-co-glycolic-acid)copolymer gel(gel group),and porous tantalum surface coated with osteoblastic induction factor slow-release system(slow-release system group),and co-cultured for 5 days.The surface cytoskeleton of the material was observed by phalloidine staining.Cell proliferation was detected by flow cytometry.Western blot assay and RT-qPCR were used to detect the protein and mRNA expressions of type Ⅰ collagen,osteopontin,and RUNX-2 on the surface cells of the material. RESULTS AND CONCLUSION:(1)Phalloidine staining showed that MG63 cells adhered to and grew on the surface and inside of the three groups of porous tantalum,and the matrix secreted by the cells covered the surface of the material.(2)Flow cytometry showed that the cell proliferation in the slow-release system group was faster than that in the control group and the gel group(P<0.05).(3)Western blot assay and RT-qPCR showed that the protein and mRNA expressions of type Ⅰ collagen,osteopontin,and RUNX-2 in the slow-release system group were higher than those in the control group and gel group(P<0.05).(4)The results showed that the domestic porous tantalum modified by the osteogenic induction factor slow-release system was beneficial to the adhesion,proliferation,and differentiation of MG63 osteoblasts.
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BACKGROUND:Prosthesis loosening and wear are still the main problems in the failure of total ankle replacement,which are closely related to the micro-motion of the implant-bone interface,the contact stress of the articular surface and joint motion.The design of artificial joint components,including insert and tibial/talar stem prosthesis,is a key factor affecting the force,motion,and micromotion of the contact interface of the ankle joint.The development of new inserts is of great significance to improve the survival rate of artificial ankle joints. OBJECTIVE:The finite element model of the total ankle replacement model was constructed to detect the biomechanical properties of the porous structure-optimized inserts,and the effect of the porous structure-optimized inserts on reducing prosthesis micromotion and improving the contact behavior of the articular surface was analyzed. METHODS:Based on the CT scan data of the right ankle joint of a healthy adult and the INBONE Ⅱ system product manual,a three-dimensional model including bone and artificial joint system was established,and the total ankle replacement model(model A)was obtained after osteotomy and prosthesis installation,and then through four new types of inserts,G50,G60,D50,and D60,were obtained by transforming the porous structure of the original insert,and the original one was replaced with different inserts to establish an optimized total ankle replacement model(models B-E)corresponding to the inserts.The gait loads were applied on the five models to simulate the gait conditions.The differences in micromotion and articular surface contact behaviors at the implant-bone interface of all five models were compared. RESULTS AND CONCLUSION:(1)In the gait cycle,the micromotion of the prosthesis of the four optimized total ankle replacement models was lower than that of the original model.Compared with model A,the micromotion of the prosthesis in models B-E decreased by 5.4%,10.1%,8.1%,and 20.9%,respectively.The high micromotion area of t ??he tibial groove dome in the optimized model was significantly smaller than that of the original model.(2)The four optimized models obtained a larger articular surface contact area.Compared with model A,the average contact area of t ??he inserts in models B-E increased by 11.8%,14.7%,8.1%,and 32.6%,respectively.(3)Similar to the effect of increasing the contact area,compared with the original model,the contact stress of the optimized model decreased in varying degrees,and the value of model E decreased the most significantly(P<0.05),it is due to good mechanical properties and large porosity of the Diamond lattice that constitutes the D60-type insert.(4)The research results show that the use of porous structure to improve the inserts can improve the elasticity of the inserts and increase its ability to absorb joint impact,for favorable conditions are created for reducing micromotion at the implant-bone interface and improving joint contact behavior.
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Objective To investigate the influence of different cell structures on the static and dynamic mechanical performance of porous titanium alloy scaffolds,and to provide a theoretical mechanical basis for the application of scaffolds in the repair of mandibular bone defects.Methods Porous titanium alloy scaffolds with diamond,cubic,and cross-sectional cubic cell structures were manufactured using three-dimensional printing technology.Uniaxial compression tests and ratcheting fatigue with compression load tests were conducted to analyze the static and dynamic mechanical performances of scaffolds with different cell structures.Results The elastic moduli of the diamond cell,cross-sectional cubic cell,and cubic cell scaffolds were 1.17,0.566,and 0.322 GPa,respectively,and the yield strengths were 71.8,65.1,and 31.8 MPa,respectively.After reaching the stable stage,the ratcheting strains of the cross-sectional cubic,diamond,and cubic cell scaffolds were 3.3%,4.0%,and 4.5%,respectively.The ratcheting strain increased with increasing average stress,stress amplitude,and peak holding time,and decreased with increasing loading rate.Conclusions The evaluation results of the static mechanical performance showed that the diamond cell scaffold was the best,followed by the cross-sectional cubic cell scaffold and the cubic cell scaffold.The evaluation results of the dynamic mechanical performance showed that the cross-sectional cubic cell scaffold performed the best,followed by the diamond cell scaffold,whereas the cubic cell scaffold performed the worst.The fatigue performance of the scaffold is affected by the loading conditions.These results provide new insights for scaffold construction for the repair of mandibular bone defects and provide an experimental basis for further clinical applications of this scaffold technology.
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Objective: The study's objective is to create biodegradable porous scaffolds that are filled with natural vanillin and assess their in vitro antibacterial activity.Methods: Scaffolds were fabricated by blending different ratios of chitosan and gelatin along with vanillin using the freeze-drying method. Then the following characterization and evaluation of scaffolds, such as FTIR, SEM, porosity, swelling behaviour, degradation studies, in vitro drug release, and antibacterial studies, were carried out.Results: All of the scaffolds that were created had heterogeneous, well-connected pores and were pale yellow in color. This was validated by SEM, where the porosity is greater than 80% and the mean pore size ranges from 105.25±6.35 µm to 188.58±7.51 µm. With an increase in gelatin concentration, all of the scaffolds showed the maximum water absorption and retention capabilities of 760.15%±4.38% and 664.73%±5.82%. In the 7-day degradation investigation, all samples lost close to 60% of their mass. In the formulation CG11, the vanillin was released gradually over about 96 h. According to the present study, the developed scaffolds CG13-A and CG13-B, as well as CG11-A and CG11-B, displayed a higher zone of inhibition.Conclusion: Due to its potent antibacterial capabilities, it may be inferred from the current research that vanillin clothed in chitosan-gelatin scaffolds would be a superior option for treating various wound infections, including diabetic wounds.
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Purpose: There is no ideal treatment paradigm for paralytic ectropion. This study evaluated lower eyelid spacers and the efficacy of a novel lower eyelid thin profile, bio?integratable, porous polyethylene. Methods: A retrospective review of 15 consecutive patients who underwent thin?profile porous polyethylene implantation and canthoplasty for paralytic ectropion was carried out. A comprehensive literature review of spacers for paralytic ectropion and retraction using the Pubmed database with search terms “[implant or graft or spacer] and [paralytic ectropion or paralytic retraction],” “graft and paralysis and ectropion,” “implant and paralysis and ectropion,” “graft and paralysis and retraction,” and “implant and paralysis and retraction” was carried out. Results: The mean patient age was 69 years (range: 50–88). Lagophthalmos improved from a mean of 5.7 mm (SD = 3.3, range 3–14 mm) to 1.4 mm (SD = 1.1, range 0–3.5 mm), P < 0.0001. MRD 2 improved from a mean of 6.7 mm (SD = 2.3, range 2–12 mm) to 4.2 mm (SD = 0.9, range 3–6 mm), P = 0.0005. No patients needed additional lower eyelid surgery. There were no implant exposures at a mean follow?up of 7.6 months (SD = 7.9, range 0.7–21.6 months). Detailed literature review revealed that hard palate and ear cartilage are the most reported spacers, each with unique disadvantages. Conclusion: The thin?profile porous polyethylene implant is a useful addition to the management of symptomatic paralytic ectropion. Meaningful comparison of lower eyelid spacers is difficult because of variations in surgical technique, spacer size, and poorly reported outcome data. No spacer proves superior
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【Objective】 To investigate the effects of biomimetic bone trabecular with the same porosity and pore size and regular porous structure on the adhesion, proliferation, and differentiation of osteoblasts, so as to provide theoretical basis for the improvement of osseointegration performance of titanium alloy implants. 【Methods】 The biomimetic bone trabecular and regular porous structures with the same porosity and pore size were generated by computer-aided software, and then processed into disc-shaped Ti6Al4V scaffolds with a diameter of 10 mm and a height of 3 mm by selective laser melting technology. MC3T3-E1 cells, the precursor cells of mouse osteoblasts in the logarithmic growth phase, were seeded on two kinds of scaffolds and divided into biomimetic bone trabecular group and regular porous structure group. After 3 hours of culture, acridine orange staining and phalloidin /DAPI staining were used to evaluate the number of cell adhesion. After 3 days of culture, the scaffolds were examined by scanning electron microscopy to evaluate the adhesion state of cells. After 1, 3, and 5 days of culture, the scaffolds were taken for CCK8 detection to observe the proliferation of cells. After 7 and 14 days of differentiation, alkaline phosphatase (ALP) activity was detected. After 14 days of differentiation, the expressions of osteogenesis-related genes (ALP, OCN, RUNX2) were detected by RT-PCR. After 30 days of differentiation, the scaffolds were stained with alizarin red and 100 g/L cetylpyridinium chloride was used to dissolve mineralized nodules. Calcium salt deposition was qualitatively and quantitatively detected to evaluate cell differentiation. 【Results】 The results of acridine orange and phalloidin /DAPI staining showed that the biomimetic trabecular Ti6Al4V scaffold adhered to more MC3T3-E1 cells than the regular porous structure, and the cytoskeleton of the former scaffold was more densely distributed. The results of scanning electron microscopy showed that the pseudopodia of MC3T3-E1 cells on the biomimetic bone trabecular Ti6Al4V scaffold were longer and the extension state was better than that of the regular porous structure. CCK8 test showed that the proliferation of MC3T3-E1 cells on the biomimetic trabecular bone titanium alloy scaffold was significantly higher than that on the regular porous structure on the 3rd and 5th day, and the difference gradually increased with the increase of time, with statistical significance (P<0.05). The results of cell differentiation test showed that ALP activity on the bionic trabecular scaffold was higher than that on the regular porous structure (P<0.05). The expressions of osteogenic genes (ALP, OCN, RUNX2) in MC3T3-E1 cells on the biomimetic bone trabecular titanium alloy scaffold were significantly higher than those on the regular porous structure (P<0.05). After 30 days of induction, the amount of calcium salt deposited in the bionic trabecular titanium alloy scaffold was significantly larger than that in the regular porous structure (P<0.05). 【Conclusion】 The biomimetic bone trabecular with a porosity of 65% and an equivalent pore size of 600 μm is more conducive to the adhesion, proliferation and differentiation of mouse osteoblast precursor cells MC3T3-E1 on the titanium alloy scaffold than the regular porous structure with the same porosity and pore size. It is theoretically more conducive to improving the osseointegration performance of titanium alloy implants.
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Objective To investigate effects of human postures on flow characteristics of iliac vein compression syndrome. Methods The numerical model of iliac vein was reconstructed from CT images of a typical patient with pelvic-type iliac vein compression syndrome with collateral veins. Based on the computational fluid dynamics method, the non-Newtonian model and the porous media model were adopted to describe effects of abnormal structures on blood flow and acquire the wall shear stress and pressure of iliac vein. The discrete phase model was used to study the residence conditions of erythrocytes under three human postures. Results The pressure gradient at two ends of the compressive region was lowest under lying state, while the iliac vein showed a high pressure under sitting and walking states. The local maximum wall shear stresses under three postures were found at narrow segment of the collateral vein and convergence region of two flows of right iliac vein. The maximum shear stress was largest under lying state and smallest under sitting state. The blood residence time of 52.2 s in the left iliac vein was the longest under sitting state. The residence time of 14.8 s was shortest under lying state. The blood residence time was 23.8 s under walking state. Conclusions Porous media model used to simulate the effect of abnormal structures was highly consistent with the angiography data. The venous hypertension under sitting and walking states was consistent with the clinical results, and the lying state could relieve the hypertensive condition. In terms of wall shear stress and blood residence time in iliac vein, the continual change between three human postures would cause endothelial damage and blood flow stasis alternately, thus increase the risk of thrombosis.
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As an excellent hosting matrices for enzyme immobilization, metal-organic framework (MOFs) provides superior physical and chemical protection for biocatalytic reactions. In recent years, the hierarchical porous metal-organic frameworks (HP-MOFs) have shown great potential in enzyme immobilization due to their flexible structural advantages. To date, a variety of HP-MOFs with intrinsic or defective porous have been developed for the immobilization of enzymes. The catalytic activity, stability and reusability of enzyme@HP-MOFs composites are significantly enhanced. This review systematically summarized the strategies for developing enzyme@HP-MOFs composites. In addition, the latest applications of enzyme@HP-MOFs composites in catalytic synthesis, biosensing and biomedicine were described. Moreover, the challenges and opportunities in this field were discussed and envisioned.
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Estructuras Metalorgánicas/química , Porosidad , Enzimas Inmovilizadas/química , Biocatálisis , CatálisisRESUMEN
Objective:To investigate the effect of autologous cartilage and artificial material implants on the occurrence of postoperative complications during rhinoplasty.Methods:This study included 447 patients who underwent cosmetic rhinoplasty at Hanmei Cosmetic Hospital in Dongguan. The age of enrolled patients was 18-52 years, and the mean age was 26.8±6.9 years. They were divided into an autologous cartilage group (334 patients in total) and an artificial material group (113 patients in total) according to the implant material used; the differences in postoperative complications were compared between the two groups and the influencing factors related to the occurrence of complications were analyzed.Results:The follow-up time of all patients was 3-24 months, and the mean time was 19.4 months. 51 (11.4%) of the 447 patients developed postoperative complications during the follow-up period, and the rate of functional failure in the artificial material group (16.8%) was significantly higher than that in the autologous cartilage group (9.6%) (χ 2=4.17, P=0.037). In the autologous cartilage group, the most frequent complications were irregular nasal contour, a total of 10 cases (3.0%), and infection, 8 cases (2.4%); while the most frequent complications in the artificial material group were infection, 6 cases (5.3%) and prosthesis exposure, 3 cases (2.7%). At 2-year follow-up, 32 cases of the postoperative complication rate occurred (16.8%) in the autologous cartilage group, which was significantly higher than that of 19 cases (9.6%) in the artificial material group, and the difference between the two groups was statistically significant (log-rank χ 2=4.37, P=0.039). The results of the multifactorial COX risk factor analysis showed that history of smoking ( HR=1.78, 1.21-2.29, P=0.004), previous history of rhinoplasty ( HR=2.89, 2.08-3.97, P<0.001) and use of artificial materials ( HR=1.34, 1.17-2.08, P=0.013) and external incision (protective factor, HR= 0.92, 0.78-0.98, P=0.037) were independent risk factors for the development of functional complications. Conclusions:Neither the use of autografts nor artificial implants in rhinoplasty prevents the occurrence of complications, and the types of complications occurring in both differ, with artificial grafts having a higher rate of postoperative complications.
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OBJECTIVE@#To investigate the preparation and properties of the novel silica (SiO 2)/hydroxyapatite (HAP) whiskers porous ceramics scaffold.@*METHODS@#The HAP whiskers were modified by the SiO 2 microspheres using the Stöber method. Three types of SiO 2/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO 2/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO 2/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics.@*RESULTS@#The SiO 2 microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO 2/HAP whiskers, the amorphous SiO 2 microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO 2/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO 2/HAP whisker porous ceramic was the highest. The SiO 2 microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO 2 microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity.@*CONCLUSION@#SiO 2/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.
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Animales , Durapatita , Porosidad , Vibrisas , Apatitas , Cerámica , Dióxido de SilicioRESUMEN
Introducción: las fracturas de pared de órbita pueden producir secuelas funcionales y estéticas. La indicación de reconstrucción quirúrgica, es indispensable para la recuperación de la motilidad y estética ocular. Los materiales reconstructivos más utilizados son los aloplásticos, como el titanio y el polietileno poroso de alta densidad (PPAD), el cual ha resultado exitoso en reconstrucción maxilofacial. El propósito de este estudio retrospectivo, es exponer los resultados tras el uso del PPAD en reconstrucciones orbitarias y sus posibles complicaciones. Materiales y métodos: se realizó una revisión retrospectiva de 22 pacientes donde se utilizó PPAD como material de reconstrucción en fracturas orbitarias. Se consideró para la indicación quirúrgica que el paciente presentara alguno de los siguientes signos: diplopía o síntomas vasovagales por atrapamiento muscular, restricciones en la motilidad ocular, enoftalmo mayor a 4mm. El material utilizado fue PPAD (Medpor Stryker®) puro en 17 casos y PPAD reforzado con una malla de titanio en el interior de su estructura (Medpor Titan Stryker®), en los 5 restantes. Resultados: se registraron 3 casos con complicaciones; ectropión, diplopía y ectropión con diplopía, los cuales todos fueron reversibles. No se registraron casos de infección ni complicaciones oftalmológicas postoperatoria. Discusión: los injertos autólogos fueron los primeros utilizados con resultados de compatibilidad y resistencia óptimos. El uso de PPAD como material de reconstrucción ha sido bien documentado con buenos resultados en términos de una baja incidencia de infección y óptima motilidad ocular a largo plazo.
Introduction: Orbital wall fractures can cause functional and aesthetic sequelae. When there is an indication for surgical reconstruction, this is essential for the recovery of ocular motility and aesthetics. The most commonly used reconstructive materials are alloplastics, such as titanium and porous high-density polyethylene (PPAD), which have been successful in maxillofacial reconstruction. The purpose of this retrospective study is to present the results and their possible complications in orbital reconstruction with PPAD. Materials and methods: a retrospective review of 22 patients in whom PPAD was used as reconstruction material for orbital fractures was performed. It was considered for the surgical indication that the patient presented any of the following signs: diplopia or vasovagal symptoms due to muscle entrapment, ocular motility restrictions, enophthalmos greater than 4mm. The material used was pure PPAD (Medpor Stryker®) in 17 cases, and PPAD reinforced with a titanium mesh inside its structure (Medpor Titan Stryker®), in the remaining 5. Results: 3 patients with complications were registered; ectropion, diplopia, and ectropion with diplopia, all of which were reversible. There were no cases of postoperative infection or ophthalmological complications. Discussion: Autologous grafts were the first used with optimal compatibility and resistance results. The use of PPAD as a reconstruction material has been well documented with good results in terms of a low incidence of infection and optimal long-term ocular motility
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OBJECTIVE@#To investigate the effect of porous surface morphology of zirconia on the proliferation and differentiation of osteoblasts.@*METHODS@#According to different manufacturing and pore-forming methods, the zirconia specimens were divided into 4 groups, including milled sintering group (M-Ctrl), milled porous group (M-Porous), 3D printed sintering group (3D-Ctrl) and 3D printed porous group (3D-Porous). The surface micromorphology, surface roughness, contact angle and surface elements of specimens in each group were detected by scanning electron microscope (SEM), 3D laser microscope, contact angle measuring device and energy-dispersion X-ray analysis, respectively. MC3T3-E1 cells were cultured on 4 groups of zirconia discs. The cell morphology of MC3T3-E1 cells on zirconia discs was eva-luated on 1 and 7 days by SEM. The cell proliferation was detected on 1, 3 and 5 days by cell counting kit-8 (CCK-8). After osteogenic induction for 14 days, the relative mRNA expression of alkaline phosphatase (ALP), type Ⅰ collagen (Colla1), Runt-related transcription factor-2 (Runx2) and osteocalcin (OCN) in MC3T3-E1 cells were detected by real-time quantitative polymerase chain reaction.@*RESULTS@#The pore size [(419.72±6.99) μm] and pore depth [(560.38±8.55) μm] of 3D-Porous group were significantly larger than the pore size [(300.55±155.65) μm] and pore depth [(69.97±31.38) μm] of M-Porous group (P < 0.05). The surface of 3D-Porous group appeared with more regular round pores than that of M-Porous group. The contact angles of all the groups were less than 90°. The contact angles of 3D-Ctrl (73.83°±5.34°) and M-Porous group (72.7°±2.72°) were the largest, with no significant difference between them (P>0.05). Cells adhered inside the pores in M-Porous and 3D-Porous groups, and the proliferation activities of them were significantly higher than those of M-Ctrl and 3D-Ctrl groups after 3 and 5 days' culture (P < 0.05). After 14 days' incubation, ALP, Colla1, Runx2 and OCN mRNA expression in 3D-Porous groups were significantly lower than those of M-Ctrl and 3D-Ctrl groups (P < 0.05). Colla1, Runx2 and OCN mRNA expressions in M-Porous group were higher than those of 3D-Porous group (P < 0.05).@*CONCLUSION@#The porous surface morphology of zirconia can promote the proliferation and adhesion but inhibit the differentiation of MC3T3-E1 cells.
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Diferenciación Celular , Proliferación Celular , Cerámica , Osteoblastos , Osteogénesis , Porosidad , CirconioRESUMEN
Objective:To analyze the effects of a novel type of polydopamine (PDA)-coated porous titanium alloy scaffolds loaded with zoledronic acid-gelatin nanoparticles (ZOL-GNPs) for topical sustained drug release on osteoclasts in vitro. Methods:After porous titanium alloy scaffolds were fabricated using electron beam melting technique and ZOL-GNPs with different ZOL concentrations (0, 1, 10, 50, 100, 500 μmol/L) were prepared by desolvation method, PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were constructed by combining the two. The characteristics of the scaffolds were analyzed. The biomechanics of 3 different scaffolds (bare porous titanium alloy scaffolds, PDA-coated porous titanium alloy scaffolds, and PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs) were investigated. Drug release detection was carried out by high performance liquid chromatography on the 1st, 4th, 7th, 14th, 21st, and 28th days respectively. The osteoclasts were inoculated into the novel scaffolds with different ZOL concentrations. The expression of osteoclast-related genes was detected by real-time quantitative (RT)-polymerase chain reaction (PCR); the expression of osteoclast-related proteins was detected by Western-blot.Results:The PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were successfully constructed. Electron microscope scanning showed that the GNPs were well spheroidized, smooth in surface, and uniformly dispersed, with a particle size of (243.6±63.4) nm. The ZOL-GNPs were uniformly compounded on the surface and in the pores of the scaffolds, and the spheres were regular in shape with no adhesion. The biomechanical experiments showed that the elastic moduli of the porous titanium alloy scaffolds under 3 different conditions were (1.81±0.12) GPa, (1.80±0.23) GPa and (1.81±0.15) GPa, showing no significant difference ( P> 0.05). The drug release percentage in the porous titanium alloy scaffolds was obviously high on the first day, and increased gradually and slowly in the subsequent 27 days. In the scaffolds with a low concentration ZOL, more osteoclasts adhered and proliferated; in the 50 μmol/L scaffolds, spheroid cells appeared; the spheroid cells increased and even apoptosis occurred with an increase in the ZOL concentration. RT-PCR showed that the expression of Ctsk gene and TRAP gene increased with the increased ZOL concentration, peaked in the 50 μmol/L scaffolds, and then decreased with the increased concentration, showing statistically significant differences ( P < 0.05). Western-blot showed that the expression pattern of Ctsk and TRAP was similar to that of their related genes. Conclusions:The novel PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs demonstrate good mechanical properties and an anti-osteoporosis effect via their topical sustained drug release. The scaffolds with a ZOL concentration of 50 μmol/L may exert the best effect on inhibition of osteoclasts.
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Objective:To explore the short-term outcomes of reconstruction of tumorous critical bone defects at femoral shaft with a 3D printed ultra-short stem with a porous structure.Methods:From September 2016 to June 2018, 8 patients underwent reconstruction of critical bone defects with a 3D printed ultra-short stem with a porous structure after resection of femoral shaft malignant tumor at Department of Orthopaedics, West China Hospital. There were 4 males and 4 females, with an average age of 36.9 years (from 11 to 61 years). Their preoperative Enneking staging was stage Ⅱb in all. There were 3 osteosarcomas, 2 Ewing sarcomas, 2 chondrosarcomas and one periosteal osteosarcoma. Preoperative CT/MRI image fusion technology was used to define the surgical boundary, design the guide plate and prosthesis, and perform surgical simulation. Tomosynthesis-shimadzu Metal Artefact Reduction technology was used to evaluate osseointegration. Complications and bone oncology prognosis of the patients were documented. The lower limb function of the patients was evaluated using Musculoskeletal Tumor Society (MSTS) 1993 scoring and knee range of motion.Results:The overall follow-up time ranged from 36 to 50 months, averaging 42.8 months. During operation one patient sustained a periprosthesis fracture, the union of which was followed up after wire assisted fixation. There was no local tumor recurrence, lung metastasis or death. The last follow-up revealed good osseointegration and basically isometric lower extremities in all cases. There was no such a complication as aseptic loosening of the prosthesis, deep infection or prosthesis fracture during the follow-up period. At the last follow-up in the 8 patients, the flexion range of the knee joint was 116.2°±9.1°, significantly improved compared with that before operation (98.8°±10.9°), and the MSTS score was (26.2±2.1) points, also significantly improved compared with that before operation [(21.6±1.8) points] ( P<0.05). Conclusions:Reconstruction with a 3D printed ultra-short stem with a porous structure is an accurate operation for femoral shaft tumorous bone defects. With careful preoperative design, intraoperative manipulation and strict postoperative follow-up management, this operation can lead to fine early curative outcomes for long shaft critical bone defects.
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OBJECTIVE@#To compare the effects of three different crosslinkers on the biocompatibility, physical and chemical properties of decellularized small intestinal submucosa (SIS) porous scaffolds.@*METHODS@#The SIS porous scaffolds were prepared by freeze-drying method and randomly divided into three groups, then crosslinked by glutaraldehyde (GA), 1-ethyl-3-(3-dimethylaminopropyl) carbodi-imide (EDC) and procyanidine (PA) respectively. To evaluate the physicochemical property of each sample in different groups, the following experiments were conducted. Macroscopic morphologies were observed and recorded. Microscopic morphologies of the scaffolds were observed using field emission scanning electron microscope (FESEM) and representative images were selected. Computer software (ImageJ) was used to calculate the pore size and porosity. The degree of crosslinking was determined by ninhydrin experiment. Collagenase degradation experiment was performed to assess the resistance of SIS scaffolds to enzyme degradation. To evaluate the mechanical properties, universal mechanical testing machine was used to determine the stress-strain curve and compression strength was calculated. Human bone marrow mesenchymal cells (hBMSCs) were cultured on the scaffolds after which cytotoxicity and cell proliferation were assessed.@*RESULTS@#All the scaffolds remained intact after different crosslinking treatments. The FESEM images showed uniformed interconnected micro structures of scaffolds in different groups. The pore size of EDC group[(161.90±13.44) μm] was significantly higher than GA group [(149.50±14.65) μm] and PA group[(140.10±12.06) μm] (P < 0.05). The porosity of PA group (79.62%±1.14%) was significantly lower than EDC group (85.11%±1.71%) and GA group (84.83%±1.89%) (P < 0.05). PA group showed the highest degree of crosslinking whereas the lowest swelling ratio. There was a significant difference in the swelling ratio of the three groups (P < 0.05). Regarding to the collagenase degradation experiment, the scaffolds in PA group showed a significantly lower weight loss rate than the other groups after 7 days degradation. The weight loss rates of GA group were significantly higher than those of the other groups on day 15, whereas the PA group had the lowest rate after 10 days and 15 days degradation. PA group showed better mechanical properties than the other two groups. More living cells could be seen in PA and EDC groups after live/dead cell staining. Additionally, the proliferation rate of hBMCSs was faster in PA and EDC groups than in GA group.@*CONCLUSION@#The scaffolds gained satisfying degree of crosslinking after three different crosslinking treatments. The samples after PA and EDC treatment had better physicochemical properties and biocompatibility compared with GA treatment. Crosslinking can be used as a promising and applicable method in the modification of SIS scaffolds.
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Humanos , Materiales Biocompatibles/química , Reactivos de Enlaces Cruzados/química , Porosidad , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Pérdida de PesoRESUMEN
Rutin,a flavonoid found in fruits and vegetables,is a potential anticancer compound with strong anti-cancer activity.Therefore,electrochemical sensor was developed for the detection of rutin.In this study,CoWO4 nanosheets were synthesized via a hydrothermal method,and porous carbon(PC)was prepared via high-temperature pyrolysis.Successful preparation of the materials was confirmed,and character-ization was performed by transmission electron microscopy,scanning electron microscopy,and X-ray photoelectron spectroscopy.A mixture of PC and CoWO4 nanosheets was used as an electrode modifier to fabricate the electrochemical sensor for the electrochemical determination of rutin.The 3D CoWO4 nanosheets exhibited high electrocatalytic activity and good stability.PC has a high surface-to-volume ratio and superior conductivity.Moreover,the hydrophobicity of PC allows large amounts of rutin to be adsorbed,thereby increasing the concentration of rutin at the electrode surface.Owing to the syn-ergistic effect of the 3D CoWO4 nanosheets and PC,the developed electrochemical sensor was employed to quantitively determine rutin with high stability and sensitivity.The sensor showed a good linear range(5-5000 ng/mL)with a detection limit of O.45 ng/mL.The developed sensor was successfully applied to the determination of rutin in crushed tablets and human serum samples.
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RESUMO O objetivo deste trabalho foi apresentar, por meio da técnica dinâmica dos fluidos computacional (CFD), dois métodos utilizados nas representações conceitual e física da vegetação em meio aquático: meio poroso e elementos geométricos simplificados. Três estudos de caso, que incluem um wetland flutuante e manchas de vegetação, exemplificam a aplicação dos métodos, mostrando suas vantagens e desvantagens. Nas etapas da geometria e da malha, a representação da vegetação como meio poroso é mais simples, prática e rápida do que a da vegetação como elementos geométricos simplificados. Porém, na parte da modelagem das equações, o método do meio poroso não consegue capturar os processos de mistura no interior da vegetação, enquanto o método dos elementos geométricos simplificados consegue.
ABSTRACT The goal of this work was to present, through computation fluid dynamics (CFD), two methods used in the conceptual and physical representation of vegetation in aquatic environments: the porous media approach and the simplified geometric elements. Three case studies, including a floating wetland and patches of vegetation, exemplify how the methods are applied, showing their advantages and disadvantages. At the geometry and meshing stage, the porous media approach shows to be simpler, faster, and more practical than the simplified geometric elements. However, in the equation modeling, the porous media approach is not able to capture the mixing processes inside the vegetation, while the simplified geometric elements method can capture those processes.