The investigation of the surface/interface of hard tissue implant materials is very important for improving their properties and application. This paper reviews the research progress and tendency of studies on the surface/interface for hard tissue implant, especially on titanium and titanium alloys, based on the law of hard tissue implant. The improvement of the bone regeneration and antibacterial properties of titanium-based alloys by surface modification has become the hot topics in recent years. Generally, loading growth factors and coating bioactive ceramics onto the surfaces of titanium and its alloys are valid ways to improve their ability of bone regeneration. And loading antibiotics and antibacterial agents have been proven to be an effective method to improve the antibacterial property of titanium implant. With the development of nanotechnology and biotechnology as well as the innovation of surface modification technologies, it is expected that to obtain titanium implants with combining bone regeneration and antibacterial properties by the hybrid surface modification.

To meetthe requirement of scaffold in bone tissue engineering with controllable macroand micro pores and good mechanical properties, chitosan-nanohydroxyapatite 3Dporous scaffolds were fabricated by low- temperature depositionmanufacturing. A load force driven injecting nozzle was proposed and developedto extrude natural derived polymers. Strand of biomaterials was extruded steady,uniformly and bonded to each other well. Hierarchial structure of scaffold wasstudied. Morphology of scaffold’s pores contains macropores and micropores. Macroporesare fabricated controllably according to fabricating path. Morphology of microporesare affected by materials ratio and fabricating temperature, cross-link, etc. A higher nanohydroxyapatite ratioleads to smaller micropores. Larger micropores are obtained under lowerfabriacating temperature. Cross-link causes micropores become smaller. Resultsof in vitro mouse MC3T3-E1 cellculture studies reveal a good biocompatibility for a high nanohydroxyapatitecontent scaffold. The regular and highly interconnected macropores ensure cellsto migrate into the center of 3D scaffold.

The pore interconnectivity isa key factor for the application of porous bioceramics as bone tissue engineeringscaffolds. Packed wax spheres were treated with dimethyl benzene and acted as theporogen for the preparation of porous ceramic scaffolds, in order to increasethe inter-sphere connectivity. The morphology, porosity, shrinkage, and thecompressive strength of the obtained ceramic scaffolds were analyzed. The cellcompatibility of the scaffolds was evaluated with Sprague-Dawley (SD) osteoblasts.The results showed that the pore interconnectivity and volumetric porosity weresignificantly increased by the dimethyl benzene treatment. Scaffolds with differentporosities had similar shrinkage. Osteoblasts migrated deeply into the centerof the porous ceramic scaffold through the interconnected pores and got normalactivity. Porous scaffolds with better interpore connectivity could provid morespace for the proliferation of osteoblasts.

Hydroxyapatite (HA) powders containing differentconcentrations of astragalus polysaccharides (APS) were synthesized by a wetchemical method. The effect of APS on the crystal structure, crystallinity andcrystal size of HA was characterized by XRD, the crystal morphologies of HA and HA/APS were characterized by TEM, the particle sizeand specific surface area of HA were detected by laser partical size distributionanalyzer, automated surface area and pore size analyzer, respectively. Furthermore,the effective concentration of APS on MC3T3-E1 osteoblasts, HA/APS onosteoblastic activity and differentiation was evaluated by Alamar blue, MTT andalkaline phosphatase assay. Cell morphologe was observed by light microscope.The results showed that the crystal structure, crystallinity andcrystal size of HA were not obviously effected by the presence of APS. Crystal morphologies of HA/APS was almost the samecompared with HA, the average particle size of HA was 1.17 μm and specificsurface area was 132.194 m²/g. The effect of APS on osteoblasts wastime and dose-dependent, APS concentrations within 80-200 μg/mL enhanced osteoblastic activity and ALPexpression, HA/APS enhanced osteoblastic activity and the osteoblasts hadintegrated morphology. It can be concluded that 0.5 g of HA containing 100-250 μm APS can promote osteoblastic activity. HA/APShas the promising potential as bone defect filling material for clinical applications.

The extract of drynaria,a traditional Chinese medical herb, was added into dicalcium phosphate dihydrate(DCPD) with concentration of 5wt%, 10wt% and 15wt% to form drug-loaded calciumphosphate cement (CPC). The effects of drynaria on the physichemical propertiesand drug release behavior of CPC were characterized by Gilmore needle tests,X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), compressivetests, scanning electron microscope (SEM) and UV-Vis spectrophotometry (UV-Vis).The effects of drynaria-loaded CPC on the morphology, proliferation, and differentiation of MC-3T3osteoblast were evaluated by SEM, Alamar blue assay, and alkaline phosphataseassay, respectively. It was found thatthe addition of drynaria increased the setting time and compressive strength ofCPC in dose-dependent manners. The addition of drynaria also accelerated theinitial hydration of CPC, but inhibited the subsequent conversion ofα-tricalcium phosphate, which were closely related to the concentration of drynaria.In comparison, the phases of CPC hydration products were not affected by drynaria.Drynaria-loaded CPC consisting of platyand acicular crystals were more compact than the control CPC. The drug releaseprofile exhibited an initial fast release stage followed by a slow releasestage, which was fit to the diffusion-controlledHiguchi model. The effect of drynaria-loaded CPC on osteoblastswas time- and dose-dependent. CPC loaded with 5wt% and 10wt% drynaria significantlypromoted osteoblast proliferation after culture for 5d (P<0.01). After cultured withdrynaria-loaded CPC for 7d, osteoblasts proliferated steadily. Osteoblasts cultured on drynaria-loaded CPCs and controlCPC showed similar differentiation. Osteoblasts with a normal morphology wereobserved on the surface of drynaria-loaded CPC, indicating an excellentbiocompatibility.

In order to improve the interfacialbonding properties of collagen-hydroxyapatite (Col-HA) composite, gum Arabicwas introduced in the system. Ca(NO₃)₂?4H₂O, (NH₄)₂HPO₄, aciddissolved collagen, and gum Arabic were used as the raw materials to in situ preparecollagen-hydroxyapatite/gum Arabic (Col-HA/Gum A) composite. Crystallite phase,chemical composition, and micro-morphology of the composite were characterizedby XRD, FT-IR, and SEM. The effects of gum Arabic on the structure andproperties of the collagen-hydroxyapatite composite were analyzed. The resultsindicate that both the interface structure and the surface morphology of thecollagen-hydroxyapatite composite are changed by the introduction of gumArabic. With increasing the amount of gum Arabic in the system, the sizes ofthe crystal grain and the crystallinity of the Col-HA composite are decreased.Both the hydrophilic properties and the enzymatic degradation capacity <>invitro of the composite are decreased significantly (P<0.01), whilst the mechanical properties of the composite areimproved in a certain range. Complexes of protein-polysaccharide can be formedbetween the gum Arabic and the collagen or collagen-hydroxyapatite, and the gumArabic can act as a cross-linking agent in the new composite.

To develop biomimetic fibroin/apatite composites with bone-like structure byalternate soaking method, the degummed natural fibroin fibers were pretreatedby soaking into CaCl₂:EtOH:H₂O (<>n(CaCl₂):<>n(EtOH):<>n(H₂O)=1:2:8) solution for given time and then soaked into calciumsolution and phosphate solution, respectively, to fabricate fibroin/apatite composites. The effects of pretreatment time andthe alternate soaking times on fibroin microstructure and fibroin/apatitecomposites were examined by SEM, FTIR, XRD and TGA techniques. The pretreatmentusing CaCl₂:EtOH:H₂O(<>n(CaCl₂):<>n(EtOH):<>n(H₂O)=1:2:8) solution makes fibroin fiber exhibit rougher surface and higher internalporosity, which is beneficial to interaction of calcium ion and residue groupssuch as -COOH, –OHand -CONH- from fibroin, and then improvethe deposition of apatite on fibroin fibers. The homogeneous apatites withoriented <>c-axis were formed on the pretreated fibroin fibers. Moreover,there are more than 30wt% apatites deposited on fibroin fibers after alternatesoaking for more than 3 times. The fibroin/apatite composite has potential tobe applied as bone repair materials.

The biological HA in the body differs from that of pure HA in stoichiometry,composition, physical properties and mechanical properties, because this HA isparticularly prone to ion substitution. As a cation that can substitute forcalcium in the structure of hydroxyapatite, strontium provokes an increasinginterest because of its beneficial effect on bone formation, and prevention ofbone resorption. Here, strontium-substituted HA powders were prepared by thehydrothermal method at 180℃ for 8 h using Ca(NO₃)₂·4H₂O, (NH₄)₂HPO₄and Sr(NO₃)₂ as reagents. X-ray diffraction, Fouriertransform infrared spectroscope, transmission electron microscope, energy dispersiveX-ray, and thermogravimetric-differential thermal analysis were employed toinvestigate the crystalline phase, chemical composition, morphology, and thermalstability of the Sr-HA. And the cytotoxicity of Sr-HA was analyzed through MTT assay. The results showthat Sr is incorporated into the HA crystal structure and the crystal grainsize of the Sr-HA decreases as the Sr content (under 50wt%) is increased.Moreover, the HA thermal stability decreases. However, there’s no apparentdifference between the pure hydroxyapatite and all of the Sr-HA groups in cytotoxicity,which may have good biocompatibility.

Siliconhydroxyapatite cement (s-HAC) was prepared by using the mixed powders oftetracalcium phosphate and dicalcium phosphate anhydrous, and 5wt% sodiumsilicate water solutions as cement liquid. The results show that the settingtime of s-HAC is shorter than hydroxyapatite cement (HAC), and the compressivestrength of s-HAC is higher than HAC in the same situation. The XRD resultsreveal that the finally hardening product of s-HAC is hydroxyapatite structure,which is similar to that of HAC. The s-HAC in the could release calcium (Ca),phosphorus (P) and silicon (Si) ions. The <>in vitro degradability of s-HACin Tris-HCl solution is better than that of HAC. The cell culture experimentalresults indicate that the cell can attach on both the surfaces of s-HAC andHAC, and have good cell morphology. The optical density (OD) and alkalinephosphate (ALP) activity of MG₆₃ cells on s-HAC are significantlyhigher that that of HAC, indicating that the s-HAC could promote the cellproliferation and differentiation.

Bioactive calcium phosphate (Ca-P)coated titanium is the most promising bone replacement materials. Bioactive calciumphosphate (Ca-P) coated titanium has the advantages of both metal and ceramicsand has been considered as one of the most promising bone replacementmaterials. Gelatin is the denatured form of collagen and is expected to bebeneficial for hard tissue applications. The CaP/gelatin composite coatings couldcombine the bioactivity and osteoconductivity of CaP with the good characteristicsof gelatin. In the present study, The pulsed electrochemicaldeposition method was employed to deposit CaP/gelatin composite coatings ontitanium substrates. The main purpose of the study is to explore the optimumprocessing parameters of the composite coating. Electrolyte was made from themixture of the Ca-P and gelatin aqueous solution with different concentrations.SEM, XRD and FTIR were usedto characterize the composition and morphology of the coating. The coatings prepared underconstant voltage and pulse voltage electrodeposition were compared and it was foundthat the pulse voltage mode was more suitable for preparing CaP/gelatincoatings. The results indicated that Theoptimized experimental conditions were as follows,:pulse voltage range, of 0 to -1.3V, the Ca²⁺ concentrationof 5.0×10^-4 mol/L; gelatin concentration of,0.5g/L, pH value, of 5.0; temperature of,50℃. Osteoblasts were cultured on the coatings to evaluate the biocompatibilityof coatings. Alamar Blue assay indicated that the composite coatings couldfavor the proliferation of the osteoblasts.

Mesoporousbioactive glasses m58S were loaded with an anticancer drug-Epirubicin hydrochloride(EPI) and the release of the drug from the glasses was evaluated. The drugloading capacity of m58S for EPI was 40%, which was three times higher thanthat of conventional Sol-Gel bioactive glasses 58S. In phosphate buffered saline (PBS), the m58S-EPI system showed asustained release behavior. Furthermore, the release rates from the EPI-m58Ssystem increased with the decrease of pH values of the release medium. Theresults suggest that m58S is an effective anticancer drug carrier and itspH-related release behavior suggests that it has potential for design ofcontrolled drug delivery bone grafting materials.

Abstract:Multi-walled nanotubes (MWCNTs) were grown on carbonpapers by chemical vapor deposition (CVD). Adhesion and proliferation of L929 mouse fibroblasts and plateletson MWCNTs and carbon papers were investigated. The influence of different bloodprotein adsorption on the human skin fibroblasts growth was also studied. The resultsshowed that mouse fibroblasts implanted on MWCNTs tended to grow more prolificallythan those on carbon papers. The cell concentration observed on MWCNTsincreased from 1.25´10⁵ /mL (cultured for 1 d) to 4.1´10⁵/mL (culture for 7 d). No toxicity reaction was observed during the culturingperiod.By employing the adsorptionassay, it was found albumin, fibrinogen, and immunoglobulinG adhered on materials could promotethe adhesion and growth of the human skin fibroblasts. Furthermore, plateletadhesion rate on MWCNTs is lower than that on the carbon papers. These resultsindicate that MWCNTs have better tissue compatibility and blood compatibility.

A vertically aligned TiO₂ nanotube array was fabricated on the surfaceof titanium substrate in fluoride-containing electrolyes by anodization. Alternative Loop Immersion Method(ALIM) was investigated to fill TiO₂ nanotubes with the biologicalapatite in the saturated solution of Ca(OH)₂ and 0.02 mol/L (NH₄)₂HPO₄.In this way, the structure of the apatite-coating on the Ti substrate waschanged for solving the problem of coating shedding well. And the amount ofsynthetic apatite formed by ALIM was quantified according to key tubeproperties such as the tube diameter, the layer thickness, the crystalstructure (amorphous or anatase), <>etc. The effect of filling biologicalapatite of TiO₂ nanotubes fabricated in glycerol-based electrolyteat 60V is the best. And the rate of inducing biological apatite on amorphous TiO₂nanotubes with the treatment of ALIM is better than that of anatase TiO₂nanotubes. Mineralization <>in vitro experiments indicates that TiO₂nanotubes after ALIM treatment promote natural apatite formation significantlyin a simulated body fluid (SBF). Such TiO₂ nanotube arrays with ALIMtreatment, are useful as a well-adhered bioactive surface layer on Ti implantmetals for orthopaedic and dental implants.

The compact, uniform and continuousseed layers were prepared on porous α-Al₂O₃ substrateswith oval-shaped and ultrafine seed crystals by ultrasonic seeding, and then TS-1films were formed after secondary growth. The microstructure of the films couldbe regulated by changing the ratios of OH^-/Si and the crystallizationtime. SEM and XRD results reveal that when the ratio of OH^-/Si is equal to0.09, after 24h of crystallization time, the film is not interconnected. If thecrystallization time is prolonged to 48h, the film have become dense and interconnected,the crystals in which are about 500nm, and when the reaction time is prolongedto 72h, the crystallinity of the film decreases, and the surface of the film iscovered with a layer of amorphous materials. When the ratio of OH^-/Si is increasedto 0.21, after 24h of crystallization time, the crystal grains in the top layerare about 400nm and the structure of the TS-1 film is asymmetric, with a denseand uniform TS-1 layer on top, the support at the bottom, and the seed layer inbetween.

Pt based binary catalysts, which were adulterated with Feseries elements, viz Fe, Co, and Ni,were prepared using microwave heating method, with carbon black as carrier andglycol as solvent. Microstructure of the catalysts was characterized by TEM, XRD, EDX and XPS. Results showed that active metal particles wereevenly distributed on carrier’s surface. After adulterated by Fe, Co, Ni, thedistribution of active metal particles’ size became narrower and average sizedecreased from 4.57nm to 2.17nm, 2.41nm, 2.55nm, respectively. The catalystswere loaded on foam nickel (FN) with polytetrafluoroethylene latex to obtain Ptbased hydrophobic catalysts, and then their activity for hydrogen-water liquidphase catalytic exchange (LPCE) was tested. Compared with Pt/C/FN hydrophobiccatalyst, the catalytic activity of Pt based binary hydrophobic catalystsadulterated with transition metals increased in evidence. The sequence of thesecatalysts’ activity was as follows, PtFe/C/FN>PtCo/C/FN> PtNi/C/FN>Pt/C/FN. The increase of catalytic activity results from the decrease ofactive metals particles’ size, moreover, it could be attributed to thedissociation property of water on Fe series metals’ surface to some extent.

Ni-based high temperature self-lubricating IS304 (IS: Induction Sintering) composites with BaF₂/CaF₂and Ag particles as lubricants were prepared by ball milling and induction sintering techniques. The microstructure of the IS304 composites is dense and the size of selflubricating particles is very fine. BaF₂/CaF₂ particlesare in dimension of about 1 μm and particles are less than 2 μm respectively,while some BaF₂/CaF₂ particles are distributed in Cr₂O₃particles. The synthesized IS304 composites exhibite high friction coefficientin the temperature range from roomtemperature to 250℃. However, thefriction coefficient dramatically decreased at 280℃ while the friction coefficient of coarsecomposites dramatically decreased at 330-350℃ in the same test condition due to the formation of self-lubricating fluoride films. The fluoride films formed on the worn surface of synthesized composites is attributed to the size refinement and appropriate distribution offluorides, which can lead toa higher temperature rise (flash temperature) at the instantaneous contactingsurface.

Theaqueous gelcasting was used to prepare 0.9Al₂O₃-0.1TiO₂ceramics. The microstructures, phase compositions and microwave dielectricproperties of sintered 0.9Al₂O₃-0.1TiO₂ceramics were investigated. With the help of proper calcination temperature(1200℃)and continuous and slow cooling process as annealing treatment, the Al₂TiO₅secondary phase was successfully eliminated. Compared with conventional drypressing method, bigger grains, less pores and more uniform microstructures areobserved in the 0.9Al₂O₃-0.1TiO₂ ceramicsprepared by aqueous gelcasting. Therefore, much better microwave dielectricproperties are obtained in the ceramics prepared by aqueous gelcasting with e_r = 10.71, Q x  f = 20421GHz, t_f = 1.3 x 10^-6/℃, whereas that of ceramics preparedby dry pressing are e_r = 10.89, Q x f = 11938GHz, t_f = 1.4 x 10^-6/℃.

A kind of nanoporous carbon has been successfully prepared fromsugarcane bagasse through a facile microwave-induced ZnCl₂activation and tested as electrode material in ionic liquid supercapacitor. Theas-prepared nanoporous carbons are systematically characterized by a variety ofmeans such as N₂ adsorption, SEM (scanning electron microscope) andTEM (transmission electron microscope). Characterization results reveal thatthe pore size of nanoporous carbons can be tuned from 2.5 nm to 7 nm by simplyadjusting the concentration of ZnCl₂ solution from 20 wt% to 60 wt%. The nanoporous carbonsare tested as electrode materials in ionic liquid using different electrochemicalmeans such as cyclic voltammetry, constant current charge-discharge andelectrochemical impedance spectroscopy. As evidenced by electrochemicalmeasurements, the capacitive performances of the carbons are closely related totheir pore sizes. It has beendemonstrated that large pore size benefits the good capacitive performance ofnanoporous carbon in ionic liquid electrolyte.