Experimental Study on Polymer Artificial Bone with HA Coated and Fiber Liners

1Introduction HA(hydroxyapatite)wasakindofbioactiveceram ics,whichhadexcellentbiocompatibilityandtissueaffin ityinthatitscomponentsweresimilartothoseofhuman bone[1].Soitwasthebestknownhumanbonesubstitute,andunprecedentedeffecthadbeenharvestedinrecenttwo d…     

The extracorporeal circuit: Materials,problems, and solutions

The extracorporeal circuit in hemodialysis and related therapies facilitates passage of blood to and from the patient and forms an integral link with the safety systems of the proportioning system. Historically, elements of the circuit were subject to problems such as spallation introduced by the blood pump and plasticizer from the tubing sets leaching into the blood. Many of these early issues have been largely resolved, although there is still potential for further improvement and innovation. The introduction of such improvements and innovations into clinical practice is critically dependent upon their cost and benefit to patient and renal unit staff.     

Swelling kinetics of a hydrogel of poly(ethylene glycol) and poly(acrylamide‐co‐styrene)

A hydrogel incorporating the hydrophilic polymer poly(ethylene glycol) and a copolymer of acrylamide and styrene was synthesized, and the dynamics of the water‐sorption process were studied. The effects of the composition of the hydrogel and the temperature of the swelling medium were investigated with respect to the water‐sorption characteristics of the hydrogel, and the kinetic parameters, including the swelling exponent and diffusion constant, were evaluated. The hydrogel was also judged for the antithrombogenic property of its surface. The experimental findings were explained on the basis of the core–shell polymeric structure of the hydrogel. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1419–1428, 2002     

Controlling the morphology of polyurethane/polystyrene interpenetrating polymer networks for enhanced blood compatibility

Polyurethane (PU)/polystyrene (PS) IPNs were simultaneously synthesized at 80°C, controlling the reaction kinetics to change the morphology. Polymerization kinetics of styrene was controlled by the content of initiator, and that of polyurethane by the catalyst concentration. The effect of the initiator and the catalyst on the polymerization rate was analyzed by NMR spectroscopy and FTIR. Gelation time was also measured by using the advanced rheometric expansion system (ARES). Samples with sea‐and‐island morphology were obtained, when the polymerization rate of PS was relatively slow, and the phase separation time was long. When the polymerization rate of PS was relatively fast, and the phase separation time was short, cocontinuous morphology was obtained. The degree of phase separation and surface roughness decreased, as the rate of PU network formation was increased, and the phase‐continuity was increased. The in vitro blood‐compatibility tests showed that the surface roughness was an important factor on the adsorption of fibrinogens and platelets. A large amount of fibrinogens and platelets were adsorbed on the relatively rough surface of samples showing sea‐island morphology. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 379–387, 2002; DOI 10.1002/app.10358     

基于表面生物学改性的多孔状二氧化钛/磷灰石复合薄膜的制备

在钛合金表面采用微孤氧化得到一层多孔状的具有生物活性的二氧化钛，经随后水热处理可形成羟基磷灰石薄膜，提高钛合金表面的生物学性能，用SEM、XRD、EDX分析了薄膜的组织、结构和化学组成，同时考察了微弧氧化得到的二氧化钛膜的生物活性，结果表明，在室温条件下从含钙、磷离子的电解液中在钛合金基体上微弧氧化得到一层二氧化钛薄膜，蒸汽处理后得到具有生物活性的二氧化钛/羟基磷灰石复合薄膜，该膜多孔均匀，且生物活性高，有利于骨组织的吸附和生长。     

Evaluation of PLGA/chitosan/HA conduits for nerve tissue reconstruction

A micro-envioment for nerve cells and tissue growth were designed and constructed via surface modification of poly(L-lactide-co-glycolide)(PLGA) with chitosan and hydroxyapatite(HA). The poly(L-lactide-co-glycolide)/chitosan/hydroxyapatite (PLGA/chitosan/HA) conduits were manufactured by a combined solvent casting and particulate leaching technique. The conduits were highly porous with an interconnected pore structure and 76.5% porosity. Micropores with 50–100 micrometer diameter were formed in the conduits. In vivo application of PLGA/chitosan/HA conduits for reconstruction of 10 mm sciatic nerve defect was assessed by the walking track analysis, the quantifying of the wet weight of tibialis anterior muscle and the histological assessment. The conduits in host rats in vivo can not only be an effective in promoting regenerating of nerves but can also lead to favorable nerve functional recovery. Funded by the National Natural Science Foundation of China(No.50774096)     

Synthesis and characterization of photopolymerizable hydrogels based on poly (ethylene glycol) for biomedical applications

Hydrogels are polymeric materials widely used in medicine due to their similarity with the biological components of the body. Hydrogels are biocompatible materials that have the potential to promote cell proliferation and tissue support because of their hydrophilic nature, porous structure, and elastic mechanical properties. In this work, we demonstrate the microwave-assisted synthesis of three molecular weight varieties of poly(ethylene glycol) dimethacrylate (PEGDMA) with different mechanical and thermal properties and the rapid photo of them using 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184) as UV photoinitiator. The effects of the poly(ethylene glycol) molecular weight and degree of acrylation on swelling, mechanical, and rheological properties of hydrogels were investigated. The biodegradability of the PEGDMA hydrogels, as well as the ability to grow and proliferate cells, was examined for its viability as a scaffold in tissue engineering. Altogether, the biomaterial hydrogel properties open the way for applications in the field of regenerative medicine for functional scaffolds and tissues.     

Preparation and properties of β-tricalcium phosphate porous bioceramic

Porous β-tricalcium phosphate bioceramic (PTCP) has important roles in surgical implants because of good biocompatibility. But the low compressive strength of the ceramic limits its application. The preparation of PTCP was improved with the adjustment of the constituents and the sintering-process. A new type of PTCP material with high compressive strength was made. The compositions, microstructure and properties of PTCP were analyzed by TG-DSC, XRD, TEM, SEM and so on. The result indicates that stearic acid burns sufficiently and gives out carbon dioxide and water vapor when slowly heated between 200 ℃ and 400 ℃ so that the porous structure like coral in β-TCP bioceramic is formed. Through crystallization at 470 ℃ and 570 ℃, more CaO-P2O5 glass-cement is converted into crystallite-glass, which is beneficial for improving the compressive strength of β-TCP bioceramic.PTCP can form a support action in bone imperfect section with good solubility.     

钙磷层对NiTi形状记忆合金与骨组织结合特性的影响

用化学处理的方法 ,在NiTi合金表面生成钙磷 (Ca P)层 ,再将试样植入日本大耳兔的股骨中考察其生物相容性。试验结果表明 :经表面处理的试样和骨组织结合良好 ,并能传导新生骨的形成 ,表明经处理后有良好的生物相容性。而未经处理的试样 ,在实验范围内 ,没有观察到成骨细胞的存在及新生骨的形成     

Mild Binding of Protein to C2N Monolayer Reveals Its Suitable Biocompatibility

The development of biocompatible nanomaterials for smart drug delivery and bioimaging has attracted great interest in recent years in biomedical fields. Here, the interaction between the recently reported nitrogenated graphene (C₂N) and a prototypical protein (villin headpiece HP35) utilizing atomistic molecular dynamics simulations is studied. The simulations reveal that HP35 can form a stable binding with the C₂N monolayer. Although the C₂N–HP35 attractive interactions are constantly preserved, the binding strength between C₂N and the protein is mild and does not cause significant distortion in the protein's structural integrity. This intrinsic biofriendly property of native C₂N is distinct from several widely studied nanomaterials, such as graphene, carbon nanotubes, and MoS₂, which can induce severe protein denaturation. Interestingly, once the protein is adsorbed onto C₂N surface, its transverse migration is highly restricted at the binding sites. This restriction is orchestrated by C₂N's periodic porous structure with negatively charged “holes,” where the basic residues—such as lysine—can form stable interactions, thus functioning as “anchor points” in confining the protein displacement. It is suggested that the mild, immobilized protein attraction and biofriendly aspects of C₂N would make it a prospective candidate in bio‐ and medical‐related applications.