共查询到20条相似文献,搜索用时 591 毫秒
1.
Hu J Chen B Guo F Du J Gu P Lin X Yang W Zhang H Lu M Huang Y Xu G 《Journal of materials science. Materials in medicine》2012,23(3):711-722
In degenerative disc disease, an injectable hydrogel can fill a degenerate area completely, reduce the risk of implant migration and subsequent loss of height of the intervertebral disc, and minimise surgical defects. Here, we propose a method of preparing an injectable silk fibroin/polyurethane (SF/PU) composite hydrogel by chemical cross-linking under physiological conditions. Mechanical testing was used to determine the mechanical strength of the hydrogel. The impact of hydrogel height on the biomechanical properties was discussed to estimate the working capacity of the hydrogel for further clinical application. Rheological properties were also examined to assess the practical ability of the hydrogel for clinical application. Hydrogel injection and cell assessment is also of interest for clinical application. An SF/PU composite hydrogel can be injected through a small incision. A cell proliferation assay using bone marrow stromal cells showed positive cell viability and increased proliferation over a seven-day period in culture. Importantly, the hydrogel can be monitored in real-time using X-ray fluoroscopy during and after surgery according to the results of X-ray fluoroscopy examination, and shows good visibility based on X-ray assays. In particular, the hydrogel offers the clinically important advantage of visibility in CT and T2-weighted magnetic resonance imaging. Based on the results of the current study, the SF/AU composite hydrogel may offer several advantages for future application in nucleus pulposus replacement. 相似文献
2.
Zonggang Chen Huanye Liu Xi Liu Xiaojie Lian Zhongwu Guo Hong-Jiang Jiang Fu-Zhai Cui 《Materials science & engineering. C, Materials for biological applications》2013,33(3):1048-1053
Calcium sulfate hemihydrate (CSH) powder as an injectable bone cement was prepared by hydrothermal synthesis of calcium sulfate dihydrate (CSD). The prepared materials showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phases, implying complete conversion from CSD phase to CSH phase. Thermogravimetric (TG) analyses showed the crystal water content of CSH was about 6.0% (wt.), which is near to the theoretic crystal water value of CSH. From scanning electron microscopy (SEM) micrographs, sheet crystal structure of CSD was observed to transform into rod-like crystal structure of CSH. Most interesting and important of all, CSD as setting accelerator was also introduced into CSH powder to regulate self-setting properties of injectable CSH paste, and thus the self-setting time of CSH paste can be regulated from near 30 min to less than 5 min by adding various amounts of setting accelerator. Because CSD is not only the reactant of preparing CSH but also the final solidified product of CSH, the setting accelerator has no significant effect on the other properties of materials, such as mechanical properties. In vitro biocompatibility and in vivo histology studies have demonstrated that the materials have good biocompatibility and good efficacy in bone regeneration. All these will further improve the workability of CSH in clinic applications. 相似文献
3.
A polymer material system has been developed to propose an injectable, UV and insitu curable hydrogel with properties similar to the native nucleuspulposus of intervertebral disc. Neat hydrogels based on Tween® 20 trimethacrylates (T3) and N-vinyl-2-pyrrolidone (NVP) and composite hydrogels of same composition reinforced by nano-fibrillated cellulose were synthesized with different T3 concentrations and their curing kinetics was investigated by photorheology using UV light. The T3 concentration has an influence on the time of curing and final shear stiffness of the material. NFC does not alter the time of curing but increases the final mechanical performance of the hydrogels for a same chemical composition. Hydrogel samples, neat and composite, were then tested in unconfined compression at different hydration stages and in confined compression and their elastic modulus was determined. The amount of fluid present in the network is mostly responsible for the mechanical properties and NFC fibres proved to be an efficient reinforcement. The elastic modulus ranged from 0.02 to 8 MPa. Biocompatibility studies showed that cells are confluent at 90% and do not show any morphology change when in contact with the hydrogel. The present hydrogel can therefore be considered for NP replacement. 相似文献
4.
硫酸钙骨水泥具有良好的骨传导性,但降解速率快、生物活性差的缺点限制了其临床应用.本文将β-磷酸三钙纳米颗粒(粒径43.8±9.0 nm)和半水硫酸钙颗粒(粒径5–21μm)混合作为固相,与液相聚乙烯醇溶液(5 wt.%)按优化重量比混匀,制备了可注射自固化复合材料.该材料具有合理的自固化时间(11.7–19.2 min)及适宜的压缩强度(2.28–6.33 MPa).同时,利用镁颗粒作为成孔剂,制备出大孔径(大于100μm)的多孔支架.体外细胞实验显示,MC3T3-E1细胞伸展良好,表现出大量的板状伪足和伸展的丝状伪足,表明该复合材料无细胞毒性.将可注射复合材料植入比格犬股骨髁缺损区,10个月后骨缺损愈合良好,表明该材料具有良好的骨缺损修复潜力. 相似文献
5.
Pierre Dalmay A. Smith T. Chotard P. Sahay-Turner V. Gloaguen P. Krausz 《Journal of Materials Science》2010,45(3):793-803
In the last few years, eco friendly materials have become an important part of the building materials market. Natural fibres
are already used in various types of materials, like plastics, concrete and lime-based products. They demonstrate different
attributes like the combination of good mechanical, thermal and acoustic properties that allow these types of materials to
be used for different applications. The main drawback associated with plaster is its brittleness, especially under tensile
stress. Therefore, it is interesting to investigate different methods that could potentially enhance the mechanical properties
of plaster. Adding fibres to gypsum to obtain a composite material is one way to improve the behaviour of the product, especially
after the failure of the matrix. The aim of this work was to the study the effects of adding natural fibres, namely hemp and
flax fibres, on the setting time of plaster and the mechanical properties of the composite matrix. It was shown that hemp
delayed the setting of plaster, unlike flax. The initial and final setting times almost doubled when hemp was added in a plaster
matrix, whereas flax fibres did not drastically change them. Different chemical treatments of hemp were tested and the impact
on the setting time was measured. The setting times of both composites made with hemp and flax were reduced once the fibres
were treated (25–40% reduction), compared to the setting time of the calcium sulphate hemihydrate alone. The mechanical properties
of the composite materials are also discussed. The behaviour of plaster was modified from brittle to a non-linear one when
fibres were added, and even at small levels of addition, flax fibres allowed slightly higher values of flexural strength to
be reached. 相似文献
6.
I. Rajzer O. Castaño E. Engel J. A. Planell 《Journal of materials science. Materials in medicine》2010,21(7):2049-2056
In this work a calcium phosphate (CPC)/polymer blend was developed with the advantage of being moldable and capable of in
situ setting to form calcium deficient hydroxyapatite under physiological conditions in an aqueous environment at body temperature.
The CPC paste consists in a mix of R cement, glycerol as a liquid phase carrier and a biodegradable hydrogel such as Polyvinyl
alcohol, which acts as a binder. Microstructure and mechanical analysis shows that the CPC blend can be used as an injectable
implant for low loaded applications and fast adsorption requirements. The storage for commercial distribution was also evaluated
and the properties of the materials obtained do not significantly change during storage at −18°C. 相似文献
7.
L. Ambrosio P. A. Netti S. Iannace S. J. Huang L. Nicolais 《Journal of materials science. Materials in medicine》1996,7(5):251-254
Different PHEMA/PCL semi-IPNs hydrogels and their relative composite systems reinforced with PET fibres have been investigated for potential use as intervertebral disc prostheses. Compression properties and water absorption were evaluated. Uniaxial compression tests on the swollen samples showed an increase of the modulus and maximum stress with increasing content of PCL and PET fibres. In particular, the composite PHEMA/PCL hydrogels showed compression properties similar to those expressed by the canine intervertebral discs in different spinal locations. The equilibrium water content of modified semi-IPNs decreased as function of the PCL and PET fibres. These tests indicate that the use of composite hydrogels as disc prostheses is very promising because it is possible to combine transport and mechanical properties which are crucial for the performance of the intervertebral disc.This paper was accepted for publication after the 1995 Conference of the European Society of Biomaterials, Oporto, Portugal, 10–13 September. 相似文献
8.
Dan Kai Dongxiao Li Xiangdong Zhu Lei Zhang Hongsong Fan Xingdong Zhang 《Journal of materials science. Materials in medicine》2009,20(8):1595-1602
An injectable calcium phosphate cement (CPC) with porous structure and excellent anti-washout ability was developed in the
study. Citric acid and sodium bicarbonate were added into the CPC powder consisting of tetracalcium phosphate (TTCP) and dicalcium
phosphate dihydrate (DCPD) to form macro-pores, then different concentrations of sodium hyaluronate (NaHA) solution, as liquid
phase, was added into the cement to investigate its effect on CPC’s performance. The prepared CPCs were tested on workability
(injectable time and setting time), mechanical strength, as well as anti-washout ability. The experimental results showed
that addition of NaHA not only enhanced the anti-washout ability of the CPC dramatically but also improve its other properties.
When NaHA concentration was 0.6 wt%, the injectable time elongated to 15.7 ± 0.6 min, the initial and final setting times
were respectively shorten to 18.3 ± 1.2 and 58.7 ± 2.1 min, and the compressive strength were increased to 18.78 ± 1.83 MPa.
On the other hand, Addition of NaHA showed little effect on porous structure of the CPC and enhanced its bioactivity obviously,
which was confirmed by the apatite formation on its surface after immersion in simulated body fluid (SBF). In conclusion,
as an in situ shaped injectable biomaterials, the CPC with appropriate addition of NaHA would notably improve its performance
and might be used in minimal invasive surgery for bone repair or reconstruction. 相似文献
9.
In the present study, cetyltrimethyl ammonium bromide (CTAB) was introduced to an injectable calcium phosphate cement (CPC) to produce macropores during the setting process to accelerate the absorbing ability in vivo. The effects of CTAB on the rheological properties, injectability, setting time, compressive strength, phase evolution, microstructure and degradation rate of CPC were studied. The results showed that the addition of CTAB increased the viscosity and yield stress, and decreased the injectability of the cement pastes. The macroporosity and total porosity increased and the compressive strength of the cement obviously decreased with the increase of CTAB. The macroporosity of the CPC prepared at 5 mM CTAB solution reached 44.2 +/- 2.5% and the mass loss of the cement increased almost 50% as compared with the cement without CTAB. Considering the injectability, compressive strength and degradation rate of CPC, the preferred CTAB concentration was 5 mM. The injectable CPC with macropores is promising to be used in minimally invasive approach. 相似文献
10.
Nurit J Margerit J Terol A Boudeville P 《Journal of materials science. Materials in medicine》2002,13(11):1007-1014
Hydraulic calcium phosphate cements (CPCs) that are used as osseous substitutes, set by an acid–base reaction between an acid calcium phosphate and a basic calcium salt (often a phosphate). In order to gain a better understanding of the setting of the monocalcium phosphate monohydrate–calcium oxide cement that we developed and in the aim to improve its mechanical properties, the setting reaction was studied by pH-metry. The two methods described in the literature were used. In the first, cement samples were prepared then crushed after different storage periods at 37 °C, 100% RH. The powder was then immersed in pure water with stirring and the pH was measured after equilibration. In the second technique, the starting materials were poured into water while stirring and the pH were followed over time. The two methods gave different results. The first procedure provided information concerning the pH of the surrounding liquid following the partial dissolution of the cement components, rather than any information about pH changes during setting. The second method is more appropriate to follow the pH variations during setting. In this second procedure, the effects of different parameters such as crushing time, stirring rate, liquid-to-powder (L/P) ratio and temperature were investigated. These parameters may impact substantially on the shape and position of the pH=f(t) curves. One or three pH jumps were observed during the setting depending on the composition of the liquid phase. The time at which these pH jumps occurred depended on the pH of the liquid phase, the concentration of the buffer, the crushing of starting materials, the L/P ratio and the temperature. Good linear correlations were obtained (i) between the time of the pH jumps and the L/P ratio and the temperature and (ii) between the time of the first pH jump and the compressive strength and the final setting time of the cements prepared with different liquid phases. It may be assumed in view of these correlations that the results obtained in dilute solution may be extrapolated to the conditions of cement sample preparation and that the mechanical properties of the cement are directly related to the phenomena that occur at the first pH jump which corresponds to precipitation of dicalcium phosphate dihydrate. 相似文献
11.
可注射纳米磷灰石/高分子复合骨修复材料的性能 总被引:3,自引:0,他引:3
制备了一种新型可注射纳米磷灰石/聚酰胺66复合材料,研究了其可注射性能、在生理盐水中的凝结时间以及抗压强度.结果表明:纳米磷灰石/聚酰胺66复合材料可用针管注射,能在空气、生理盐水和血液中固化,有合理的凝结时间,高的抗压强度,可用于骨缺损的修复.在固化过程中,材料中的聚酰胺发生了物相变化,聚酰胺从结晶型相转变成无定型相,在水中固化后又转变成结晶型相;金属盐的存在破坏了聚酰胺分子间的氢链,导致了材料在固化过程中聚酰胺结构发生了变化.该材料生物相容性和生物活性好,能促进骨缺损的修复和重建。 相似文献
12.
Ellä V Kellomäki M Törmälä P 《Journal of materials science. Materials in medicine》2005,16(7):655-662
The suitability of two different implant types for the replacement of the intervertebral disc was studied in vitro. Self-reinforced poly-L-lactide (SR-PLLA) screws Ø 4.5 mm were studied 24 weeks in vitro and cylindrical implants with elastic nucleus made of poly(L/D)lactide 96/4, poly(L/DL)lactide 70/30, Bioactive Glass n:o 13–93 and Polyactive® 1000PEOT70PBT30 were studied 15 weeks in vitro. The cylindrical implant mimics the size and shape of the intervertebral disc. During the in vitro, there were no changes in compression properties with either implant types. The screws had sufficient modulus for intervertebral ossification in the canine model and the cylindrical implant showed also sufficient mechanical properties. These results suggest that both implant types could be used in clinical testing. 相似文献
13.
Sarda S Fernández E Llorens J Martínez S Nilsson M Planell JA 《Journal of materials science. Materials in medicine》2001,12(10-12):905-909
One scientific and technological aspect of main importance to the medical profession is to develop injectable calcium phosphate cements (CPCs) to be used through minimally invasive surgery techniques with still suitable mechanical and biodegradable properties. The objective of this research was to study the influence of several technological factors on the injectability of CPCs. This was performed by studying the rheological behavior of the cement pastes during their initial setting. Cement rheology was approached by looking at the creep response of apatitic cements as a function of the shear stress, the liquid-to-solid (L/S) ratio, the temperature and the addition of organic admixtures. Results showed creep experiments to be a finer method to detect characteristic setting times than other established subjective procedures. However, of all transition times detected none but the dough time seems to be of relevant importance when injectability of cement is concerned. Creep experiments also showed that the addition of organic admixtures such as citric acid increased injectability by retarding the hydration time. 相似文献
14.
In this work, the uniform design method was applied to arrange the experimental scheme for optimizing formulation of friction materials. The friction and wear of the friction materials based on the optimized formulation was carried out on a constant speed friction tester (JF150D-II), using pad-on-disc contact mode against gray cast iron disc. The worn surfaces of the friction materials were examined by scanning electron microscopy (JSM5310) and the friction mechanism was discussed. The results showed that the uniform design method was appropriate for finding the optimum formulation of the friction materials with better properties. Compared with two conventional friction materials, the friction materials based on the optimized formulation possessed higher and stable friction coefficient and higher wear resistance, even at the disc temperature of 350°C. The adhesion, strain fatigue and abrasive wear were the main wear mechanisms of the friction materials. Tribo-chemical phenomenon and plastic deformation existed on the worn surface layer. 相似文献
15.
Gangfeng Hu Luwei Xiao Hong Fu Dawei Bi Haitao Ma Peijian Tong 《Journal of materials science. Materials in medicine》2010,21(2):627-634
Injectable calcium sulphate/phosphate cement (CSPC) with degradable characteristic was developed by introduction of calcium
sulphate (CS) into calcium phosphate cement (CPC). The setting time, compressive strength, composition, degradation, cells
and tissue responses to the CSPC were investigated. The results show that the injectable CSPC with optimum L/P ratio exhibited
good injectability, and had suitable setting time and mechanical properties. Furthermore, the CSPC had good degradability
and its degradation significantly faster than that of CPC in Tris–HCl solution. Cell culture results indicate that CSPC was
biocompatible and could support MG63 cell attachment and proliferation. To investigate the in vivo biocompatibility and osteogenesis,
the CSPC were implanted in the bone defects of rabbits. Histological evaluation shows that the introduction of CS into CPC
enhanced the efficiency of new bone formation, and CSPC exhibited good biocompatibility, degradability and osteoconductivity
with host bone in vivo. It can be concluded that the injectable CSPC had a significant clinical advantage over CPC, and might
have potential to be applied in orthopedic, reconstructive and maxillofacial surgery, especially for minimally invasive techniques. 相似文献
16.
Zonggang CHEN Xiuli ZHANG Lingzhi KANG Fei XU Zhaoling WANG Fu-Zhai CUI Zhongwu GUO 《材料科学前沿(英文版)》2015,9(4):332-345
Minimally invasive injectable self-setting materials are useful for bone repairs and for bone tissue regeneration in situ. Due to the potential advantages of these materials, such as causing minimal tissue injury, nearly no influence on blood supply, easy operation and negligible postoperative pain, they have shown great promises and successes in clinical applications. It has been proposed that an ideal injectable bone repair material should have features similar to that of natural bones, in terms of both the microstructure and the composition, so that it not only provides adequate stimulus to facilitate cell adhesion, proliferation and differentiation but also offers a satisfactory biological environment for new bone to grow at the implantation site. This article reviews the properties and applications of injectable bone repair materials, including those that are based on natural and synthetic polymers, calcium phosphate, calcium phosphate/polymer composites and calcium sulfate, to orthopedics and bone tissue repairs, as well as the progress made in biomimetic fabrication of injectable bone repair materials. 相似文献
17.
Development of a fully injectable calcium phosphate cement for orthopedic and dental applications 总被引:4,自引:0,他引:4
A study on the development of a fully injectable calcium phosphate cement for orthopedic and dental applications is presented.
The paper describes its characteristic properties including results of biocompatibility studies.
A conventional two-component calcium phosphate cement formulation (having a powder part containing dry mixture of acidic and
basic calcium phosphate particles and a liquid part containing phosphate solution) is modified with a biocompatible gelling
agent, to induce flow properties and cohesion. The quantity of the gelling agent is optimized to get a viscous paste, which
is smoothly injectable through an 18-gauge needle, with clinically relevant setting parameters.
The new formulation has a setting time of 20 min and a compressive strength of 11 MPa. The X-ray diffraction, Fourier transform
infrared spectrometry, and energy dispersive electron microprobe analyses showed the phase to be hydroxyapatite, the basic
bone mineral. Scanning electron microscopy revealed a porous structure with particle sizes of a few micrometers. The cement
did not show any appreciable dimensional or thermal change during setting. The injectability is estimated by extruding through
needle and the cohesive property is assessed by water contact method. The cement passed the in vitro biocompatibility screening
(cytotoxicity and haemolysis) tests. 相似文献
18.
Nilsson M Carlson J Fernandez E Planell JA 《Journal of materials science. Materials in medicine》2002,13(12):1135-1141
We present a new technique, based on pulse-echo ultrasound, for monitoring the entire setting process of injectable bone cement. This research has been motivated by the lack of satisfying standards. The main problem with existing standards is the subjectivity, which leads to poor reproducibility. Because of this the results are not comparable between different research groups. A strong advantage with the proposed technique is that if low-intensity ultrasound is used, it provides a non-destructive analysis method. Once the cement paste has been applied to the measurement cell, no manipulation is needed throughout the entire setting process. The problem of the ultrasound affecting the setting of certain cement materials has been investigated, and solutions are discussed. The propagation of ultrasound is temperature-dependent, and therefore a technique for automatic compensation for temperature variations is discussed briefly. The testing was performed on -calcium sulfate hemihydrate (CSH) and mixtures of CSH and -tricalcium phosphate (-TCP). The results show that the acoustic properties of the cement are strongly correlated with the setting time, the density, and the adiabatic bulk modulus. The measured initial and final setting times agree well with the Gillmore needles standard. An important difference compared to the standards, is that the technique presented here allows the user to follow the entire setting process on-line. 相似文献
19.
I. B. MACDUFF 《Strain》1972,8(1):28-34
Useful methods of determining elastic constants employing diametrically–loaded disc and ring specimens have been proposed and applied by Durelli and Ferrer. Young's modulus may be measured from tests on a suitably dimensioned ring specimen. Subsequently Poisson's ratio may be found using a disc. The application of the methods described by the authors does not suit the case where the specimens are small and of stiff materials such as metals. In such a case sensitive means are required for measuring change in diameter with light loading. The paper indicates how this can be carried out for an aluminium alloy. The theory relating to the use of the disc for determining Poisson's ratio has been generalised to allow for measurement of change in length over part or all of a diameter. Poisson's ratio of the aluminium alloy was determined with a disc specimen 0.874 in (22.2 mm) diameter, vibrating wire strain gauges on either side of the specimen indicating change in diameter with loading. A ring was subsequently machined from the disc and similarly tested to confirm Young's modulus. 相似文献
20.
M. P. Ginebra M. G. Boltong F. C. M. Driessens O. Bermúdez E. Fernández J. A. Planell 《Journal of materials science. Materials in medicine》1994,5(2):103-107
Attempts were made to prepare magnesium-containing calcium phosphate cements. These were successful at the composition CaMg2(PO4)2xH2O. X-ray diffraction showed that such a compound is not formed but that the cement consists of magnesium phosphate precipitated on the calcium phosphate admixture. The pH of this formulation is around 10 during setting and after. The cement is injectable. Its setting time is about 10 min. In this study compressive strength values were as high as 11 MPa and the diametral tensile strength was over 2 MPa. Animal experiments must show whether it is suitable for replacement or augmentation of bone in non-load bearing situations. 相似文献