White spot lesions(WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate(...White spot lesions(WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate(NACP) with long-term calcium(Ca) and phosphate(P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACPrechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release.The rechargeable cement consisted of pyromellitic glycerol dimethacrylate(PMGDM) and ethoxylated bisphenol A dimethacrylate(EBPADMA). NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength(SBS) to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release(P40.1). Specimens after one recharge treatment(e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as "1 min 3 times") exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles(P40.1). The ion re-release concentrations at 14 days versus various recharge treatments were as follows: 1 min 3 times43 min 2 times41 min 2 times46 min 1 time43 min 1 time41 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.展开更多
Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties.Mg and its alloys are of poor co...Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties.Mg and its alloys are of poor corrosion resistance.Its high corrosion rate leads to its quick decomposition in the corrosive ambiance and as a result weakening its mechanical properties and before it is repaired,it will vanish.The corrosion and degradation rate must be controlled in the body to advance the usage of Mg and its alloys as implants.Different techniques have been utilized to boost biological properties.Plasma electrolytic oxidation(PEO)can provide porous and biocompatible coatings for implants among various techniques.Biodegradable implants are generally supposed to show enough corrosion resistance and mechanical integrity in the body environment.Much research has been carried out in order to produce PEO coatings containing calcium phosphate compounds.Calcium phosphates are really similar to bone mineral composition and present great biocompatibility.The present study deals with the usage of calcium phosphates as biocompatible coatings applied on Mg and its alloys to study the properties and control the corrosion rate.展开更多
A facile strategy to fabricate gold nanorod@polyacrylic acid/calcium phosphate(Au NR@-PAA/Ca P) yolk–shell nanoparticles(NPs) composed with a PAA/Ca P shell and an Au NR yolk is reported. The asobtained Au NR@PAA/Ca ...A facile strategy to fabricate gold nanorod@polyacrylic acid/calcium phosphate(Au NR@-PAA/Ca P) yolk–shell nanoparticles(NPs) composed with a PAA/Ca P shell and an Au NR yolk is reported. The asobtained Au NR@PAA/Ca P yolk–shell NPs possess ultrahigh doxorubicin(DOX) loading capability(1 mg DOX/mg NPs), superior photothermal conversion property(26%)and p H/near-infrared(NIR) dual-responsive drug delivery performance. The released DOX continuously increased due to the damage of the Ca P shell at low p H values. When the DOX-loaded Au NR@PAA/Ca P yolk–shell NPs wereexposed to NIR irradiation, a burst-like drug release occurs owing to the heat produced by the Au NRs. Furthermore,Au NR@PAA/Ca P yolk–shell NPs are successfully employed for synergic dual-mode X-ray computed tomography/photoacoustic imaging and chemo-photothermal cancer therapy. Therefore, this work brings new insights for the synthesis of multifunctional nanomaterials and extends theranostic applications.展开更多
Globally,vast research interest is emerging towards the development of biodegradable orthopedic implants as it overcomes the toxicity exerted by non-degradable implants when fixed in the human body for a longer period...Globally,vast research interest is emerging towards the development of biodegradable orthopedic implants as it overcomes the toxicity exerted by non-degradable implants when fixed in the human body for a longer period.In this context,magnesium(Mg)plays a major role in the production of biodegradable implants owing to their characteristic degradation nature under the influence of body fluids.Also,Mg is one of the essential nutrients required to perform various metabolic activities by the human cells,and therefore,the degraded Mg products will be readily absorbed by the nearby tissues.Nevertheless,the higher corrosion rate in the biological environment is the primary downside of using Mg implants that liberate H2gas resulting in the formation of cavities.Further,in certain cases,Mg undergoes complete degradation before the healing of damaged bone tissue and cannot serve the purpose of providing mechanical support.So,many studies have been focused on the development of different strategies to improve the corrosion-resistant behavior of Mg according to the requirement.In this regard,the present review focused on the limitations of using pure Mg and Mg alloys for the fabrication of medical implants and how the calcium phosphate conversion coating alters the corrosive tendency through the formation of hydroxyapatite protective films for enhanced performance in medical implant applications.展开更多
The aim of this study was to reconstruct surface porous structure with hundreds of micrometers and then bio-mineralize Sr-doped Calcium Phosphate(Sr-doped CaP)on Polyetheretherketone(PEEK)profile to enhance its bioact...The aim of this study was to reconstruct surface porous structure with hundreds of micrometers and then bio-mineralize Sr-doped Calcium Phosphate(Sr-doped CaP)on Polyetheretherketone(PEEK)profile to enhance its bioactivity.A surface porous structure was prepared on PEEK profile by embedding and acid-etching of SiO2 particles as porogen(SP-PEEK).Then the Sr-doped CaP was further decorated on the porous surface after sulfonation,introduction of Sr-doped CaP crystal seeds and bio-mineralization in 1.5 times simulated body fluid(BSSP-PEEK-CaP/Sr).It was feasible to reconstruct the surface porous structure with hundreds of micrometers on PEEK profile by the present method without damaging its mechanical properties.The Sr-doped CaP crystal seeds effectively promoted the bio-mineralization of bio-inertness PEEK.All as-prepared PEEK did not inhibit the proliferation of cells.ALP of bio-mineralized groups was significantly increased than that of the other groups.The BSSP-PEEK-CaP/Sr obviously affected the morphology and promoted the adhesion and spreading of cells.As a result,the cyto-biocompatibity and bioactivity of PEEK were improved after bio-mineralization.Sr-doped CaP on PEEK most likely was beneficial for cells,which was associated with the increasing of the hydrophilicity on PEEK.This study provided a candidate method to improve the osteogenesis of PEEK implants.展开更多
Perfluorocarbon emulsion has been studied as an oxygen carrier, due to its high oxygen content. In clinical trials, it has shown stability in delivering oxygen to the target region. The purpose of the present study wa...Perfluorocarbon emulsion has been studied as an oxygen carrier, due to its high oxygen content. In clinical trials, it has shown stability in delivering oxygen to the target region. The purpose of the present study was to increase the stability of the emulsion by coating its surface with calcium phosphate. A layer-by-layer method was employed to coat the flexible emulsion surface. Considering the ionic affinity of calcium and phosphate to the lecithin emulsion surface, the first layer of coating was calcium and the second layer was comprised of phosphate ion. The coated emulsion demonstrated various oxygen release times depending on the thickness of the layers: from 0.04 sec. for a thickness of 8 nm to 0.17 sec. for a thickness 38 nm. Overall, the stability of the calcium phosphate coated emulsion was increased, while its original function as an oxygen carrier was maintained.展开更多
Recently,multifunctional nanoparticles have shown great prospects in cancer treatment,which have the ability to simultaneously deliver the drug,image and target tumor cells.In this paper,we designed a luminescent nano...Recently,multifunctional nanoparticles have shown great prospects in cancer treatment,which have the ability to simultaneously deliver the drug,image and target tumor cells.In this paper,we designed a luminescent nanoparticles platform based on hydrothermal hyaluronic acid/amorphous calcium phosphate(HA-FCNs/ACP)with multifunctional properties for drug delivery,bio-imaging,and targeting treatment.HA-FCNs/ACP shows an ability to load curcumin(Cur)with pH-sensitive responsive drug release behavior and excellent biocompatibility.HA-FCNs/ACP dispersed in the cytoplasm through the overexpressed CD44 receptor that is actively targeted into human lung cancer cells(A549 cells).Meanwhile,the viability of A549 cells was significantly inhibited in vitro.The prepared HA-FCNs and HA-FCNs/ACP both exhibit excellent targeted bioimaging performance on cancer cells.Hence,the as-prepared nanoparticles have promising applications in treating tumor disease.展开更多
The utilization of Calcium Phosphate Cement(CPC)is limited due to its low mechanical strength and difficulty to seed cells deep into the scaffold.The objectives of this study were to:(1)develop a 3D-printed CPC-dopami...The utilization of Calcium Phosphate Cement(CPC)is limited due to its low mechanical strength and difficulty to seed cells deep into the scaffold.The objectives of this study were to:(1)develop a 3D-printed CPC-dopamine-metformin scaffold encapsulating human periodontal ligament stem cells(hPDLSCs),(2)investigate the effect of dopamine on the performance of CPC,and(3)evaluate the effect of microbead degradation and metformin release on the osteogenic differentiation of the released hPDLSCs.The mechanical property of the CPC scaffolds was elevated by adding dopamine,and the CPC scaffold with 7 wt.%dopamine had the highest compressive strength(7.35 MPa).Four types of microbeads with different content of alginate(oxidized alginate),hPDLSCs,and 2%metformin were fabricated.Morphological and cell counting kit tests confirm that the hPDLSCs are protected by microbeads encapsulation during the CPC setting process.The alkaline phosphatase test indicates that the osteogenic differentiation of hPDLSCs was enhanced by the fast release of cells and metformin.The microbeads consisting of 2%oxidized alginate and 2%metformin were optimal for cell delivery due to favorable cell release and osteogenic differentiation.This CPC scaffold is promising used for bone regeneration in dental,craniofacial,and orthopedic applications.展开更多
Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standard...Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standards. A number of analytical methods are presently used for the analysis of metals in the biochemical. The instrumental techniques available are Inductively Coupled Plasma (ICP/MS), X-Ray Fluorescence, UV-VIS Spectrophotometry, and Atomic Absorption Spectrometry. Flame AA has gained widespread acceptance as an analytical technique and is used for many applications. In this study, we have determined the amount of manganese metal present in Tricalcium Phosphate (TCP) using Flame Atomic Absorption Spectrophotometer. The method has high precision and accuracy. The percent recovery was found to be 99.8% for spiked sample. The results meet the requirement.展开更多
The aim of this study was to evaluate the dentinal tubule sealing and acid resistance of dentin specimens following the application of calcium phosphate glass powder prior to irradiation with a CO2(carbon dioxide)lase...The aim of this study was to evaluate the dentinal tubule sealing and acid resistance of dentin specimens following the application of calcium phosphate glass powder prior to irradiation with a CO2(carbon dioxide)laser.Dentin models simulating open dentinal tubules were divided into two groups:experimental(calcium phosphate glass slurry applied to the dentin surface)and control(no slurry applied to the surface).All specimens in the experimental group and five specimens in the control group were irradiated with a CO2 laser.The defocused laser beams(0.5 and 1 W)were applied(spot size,5 mm in diameter)from a distance of 20 mm for 10 s.The surfaces and cross-sectional areas of the specimens were examined using an SEM(scanning electron microscope).In addition,the resistance to acid was evaluated in these specimens.The open dentinal tubules in the control groups were sealed following irradiation with the CO2 laser at 0.5 W and 1.0 W.Likewise,sealing of open dentinal tubules was observed in the experimental group after CO2 laser irradiation.The acid resistance of the dentin surface was improved after CO2 laser irradiation;specimens in the experimental group presented with significantly lower amounts of Ca ion release compared to those in the control group.These findings indicate that CO2 laser irradiation alone or after the application of calcium phosphate glass powder can effectively seal the dentinal tubules and alleviate dentin hypersensitivity.展开更多
A biphasic bone grafting biomaterial based on a mixture of calcium phosphates and beta-tricalcium phosphate (<em>β</em>-TCP) phases with high nanoporosity was synthesized. The synthesis route was based on...A biphasic bone grafting biomaterial based on a mixture of calcium phosphates and beta-tricalcium phosphate (<em>β</em>-TCP) phases with high nanoporosity was synthesized. The synthesis route was based on calcium phosphate composition and the incorporation of glycolic acid as a pore former, giving a material composed of 97% <em>β</em>-TCP and 3% calcium orthophosphates (CaPO<sub>4</sub>). An<em> i</em><em></em><span></span><em>n </em><em>vitro</em> study of the purity, microstructure, crystalline domain, and pores size for the material obtained was performed by SEM analysis as well as full structural characterization. The region of interest related to the surface was determined by the specific surface area measured with the BET method. <em>In vivo</em> evaluation of bone response was performed by implanting the new low-cost biphasic manufacturing material synthesized in this work, which was compared with a biphasic material of similar chemical and microstructural composition existing in the commercial market and with higher cost called Synergy Odontit<sup><span style="white-space:nowrap;">®</span></sup> <em>β</em>-TCP. The materials were implanted separately into 5 mm diameter defects in the tibias of New Zealand White rabbits at 30, 60, and 90 days. The results obtained showed that the host tissue well accepted the new biphasic material;the presence of new bone formation was observed. A more complete resorption was observed for the new microcrystalline biphasic material compared to for a commercial <em>β</em>-TCP material.展开更多
The synthesis of mesoporous β-tricalcium phosphate(β-TCP)powder was performed by using the microemulsion approach,with hexadecyltrimethyl ammonium bromide(CTAB)/cyclohexane/n-octyl alcohol microemulsion system.The i...The synthesis of mesoporous β-tricalcium phosphate(β-TCP)powder was performed by using the microemulsion approach,with hexadecyltrimethyl ammonium bromide(CTAB)/cyclohexane/n-octyl alcohol microemulsion system.The influences of different pH values and calcination temperatures on the phase composition of the β-TCP powder were studied.The in vitro proliferation of bone marrow mesenchymal stem cells(BMSCs)in the suspensions of β-TCP powders with meso-structure was studied.The phase composition,mesoporous structure,powder morphology,cell morphology and the optical density(OD)were characterized through X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),Fourier transform infrared(FTIR)spectroscopy,Nadsorption-desorption isotherms,inverted phase contrast microscopy and Multiskan spectrum,respectively.The mesoporous β-TCP powder with specific surface area of 12.85 m^(2)/g and the average pore size 7.11 nm was obtained through the microemulsion approach(100 g/L CTAB/250 mL/L cyclohexane/250 mL/L n-octyl alcohol)with a controlled pH of 7.0,after calcinating the powder at 800℃.It was confirmed that mesoporous β-TCP powder benefits the activity of BMSCs more than the non-mesoporous β-TCP powder.展开更多
In this work wollastonite/tricalcium phosphate (W/TCP) glass-ceramics with three W/TCP weight ratios (20/80;60/40 and 80/20) were implanted in rat calvaria and the modifications taking place during implantation were s...In this work wollastonite/tricalcium phosphate (W/TCP) glass-ceramics with three W/TCP weight ratios (20/80;60/40 and 80/20) were implanted in rat calvaria and the modifications taking place during implantation were studied by Raman spectroscopy. The experimental glass-ceramics were composed of different contents of βW, αW, βTCP, αTCP, and glassy phases. Materials were implanted for 7-, 15-, 45- and 120-day periods after which the implanted materials were recovered and analyzed by FT-Raman spectroscopy. The results suggested that the αW phase reabsorbs fast during implantation in the glass-ceramics 60/40 and 80/20, whereas βTCP and αTCP glass-ceramic are gradually attenuated and replaced by biological apatite-like bands. In the glass-ceramic 20/80, the bands related to the βTCP phase remained unvaried in all analyzed periods. New bands associated with the deposition of collagenous material appeared during implantation for all 60/40 and 80/20 glass-ceramics experimental groups, but important differences in intensities between both groups. The spectra corresponding to implants of 60/40 glass-ceramic at the 120-day period were very similar to those of the control group (normal cortical bone), with regards to Raman shifts and intensities, as well as in the FWHM value of the 962 cm<sup>-1</sup> apatite band (ν1 PO4 in hydroxyapatite), evidencing that apatite deposited at the implant site has the same crystallinity than biological apatite in normal bone mineral. The glass-ceramic 20/80 behaved just as an osteoconductive filling material, while glass-ceramics 60/40 and 80/20 were able to induce deposition of organic matrix mineralized new tissue. The 60/40 glass-ceramic showed the best performance and the most similar Raman spectrum to normal cortical bone.展开更多
Calcium phosphate cements(CPCs) are frequently used to repair bone defects. Since their discovery in the 1980 s, extensive research has been conducted to improve their properties, and emerging evidence supports their ...Calcium phosphate cements(CPCs) are frequently used to repair bone defects. Since their discovery in the 1980 s, extensive research has been conducted to improve their properties, and emerging evidence supports their increased application in bone tissue engineering. Much effort has been made to enhance the biological performance of CPCs, including their biocompatibility, osteoconductivity, osteoinductivity, biodegradability,bioactivity, and interactions with cells. This review article focuses on the major recent developments in CPCs,including 3 D printing, injectability, stem cell delivery, growth factor and drug delivery, and prevascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.展开更多
AIM: To determine the effects of transplanting osteogenic matrix cell sheets and beta-tricalcium phosphate(TCP) constructs on bone formation in bone defects.METHODS: Osteogenic matrix cell sheets were prepared from bo...AIM: To determine the effects of transplanting osteogenic matrix cell sheets and beta-tricalcium phosphate(TCP) constructs on bone formation in bone defects.METHODS: Osteogenic matrix cell sheets were prepared from bone marrow stromal cells(BMSCs), and a porous TCP ceramic was used as a scaffold. Three experimental groups were prepared, comprised of TCP scaffolds(1) seeded with BMSCs;(2) wrapped with osteogenic matrix cell sheets; or(3) both. Constructs were implanted into a femoral defect model in rats and bone growth was evaluated by radiography, histology, biochemistry, and mechanical testing after 8 wk. RESULTS: In bone defects, constructs implanted with cell sheets showed callus formation with segmentalor continuous bone formation at 8 wk, in contrast to TCP seeded with BMSCs, which resulted in bone nonunion. Wrapping TCP constructs with osteogenic matrix cell sheets increased their osteogenic potential and resulting bone formation, compared with conventional bone tissue engineering TCP scaffolds seeded with BMSCs. The compressive stiffness(mean ± SD) values were 225.0 ± 95.7, 30.0 ± 11.5, and 26.3 ± 10.6 MPa for BMSC/TCP/Sheet constructs with continuous bone formation, BMSC/TCP/Sheet constructs with segmental bone formation, and BMSC/TCP constructs, respectively. The compressive stiffness of BMSC/TCP/Sheet constructs with continuous bone formation was significantly higher than those with segmental bone formation and BMSC/TCP constructs.CONCLUSION: This technique is an improvement over current methods, such as TCP substitution, and is useful for hard tissue reconstruction and inducing earlier bone union in defects.展开更多
Tooth decay is prevalent,and secondary caries causes restoration failures,both of which are related to demineralization.There is an urgent need to develop new therapeutic materials with remineralization functions.This...Tooth decay is prevalent,and secondary caries causes restoration failures,both of which are related to demineralization.There is an urgent need to develop new therapeutic materials with remineralization functions.This article represents the first review on the cutting edge research of poly(amido amine)(PAMAM) in combination with nanoparticles of amorphous calcium phosphate (NACP).PAMAM was excellent nucleation template,and could absorb calcium (Ca) and phosphate (P) ions via its functional groups to activate remineralization.NACP composite and adhesive showed acid-neutralization and Ca and P ion release capabilities.PAMAM +NACP together showed synergistic effects and produced triple benefits: excellent nucleation templates,superior acidneutralization,and ions release.Therefore,the PAMAM+NACP strategy possessed much greater remineralization capacity than using PAMAM or NACP alone.PAMAM+NACP achieved dentin remineralization even in an acidic solution without any initial Ca and P ions.Besides,the long-term remineralization capability of PAMAM+NACP was established.After prolonged fluid challenge,the immersed PAMAM with the recharged NACP still induced effective dentin mineral regeneration.Furthermore,the hardness of predemineralized dentin was increased back to that of healthy dentin,indicating a complete remineralization.Therefore,the novel PAMAM+NACP approach is promising to provide long-term therapeutic effects including tooth remineralization,hardness increase,and caries-inhibition capabilities.展开更多
The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds wi...The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone regeneration.Physicochemical properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect repair.Histological results indicated that the 3DS was highly vascularized and well combined with surrounding tissues.FS showed obvious newly formed bone tissues.AB showed the best repair effect,but it was found that AB scaffolds were partially absorbed and degraded.This study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.展开更多
Phosphorylated chitins (P-chitins) as the additives of calcium phosphate cements (CPCs) were prepared by thephosphorylation of chitin with phosphorus pentoxide in methanesulfonic acid. Their physical properties and ef...Phosphorylated chitins (P-chitins) as the additives of calcium phosphate cements (CPCs) were prepared by thephosphorylation of chitin with phosphorus pentoxide in methanesulfonic acid. Their physical properties and effects on CPCsfrom monocalcium phosphate monohydrate (MCPM) and calcium oxide (CaO) or dicalcium phosphate dihydrate (DCPD)and calcium hydroxide [Ca(OH)2] were investigated. Addition of P-chitin (Mw = 2.60 x 104; degree of substitution, DS =0.68)to the liquid phase in amounts up to 3 wt% for MCPM and CaO cements or 1.5 wt% for DCPD and Ca(OH)2 cementscould enhance the mechanical strength considerably, while little influence on the setting time was observed. However, furtheraddition of P-chitin will cause no setting.展开更多
The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with ...The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with an electrochemical work-station supplying a direct current power at potential of -0.8V （vs SCE）. The electrolyte consists of 7 mmol·L-1 CaCl2·2H2O, 3 mmol·L-1 Ca（H2PO4）2·H2O and 2.5% H2O2. NaOH and HCl solutions were used to adjust pH value. The deposited samples were characterized by X-ray diffraction and scanning electron microscope. The comparison of the deposits obtained at lower and higher pH values demonstrates that the crystallization process at the interface is favoured by high pH value. With temperature increasing, the deposited hydroxyapatite is occasionally of plate-like shape, and the width and the length of the deposited calcium phosphates at 65 ℃ are larger than those at 55 ℃. Therefore, it is confirmed that the morphology and microstructure of electrochemically deposited calcium phosphates can be regulated. Additionally, the coating formed in electrolyte with H2O2 additive is homogeneous and the evolution of H2 bubble can be eliminated.展开更多
基金supported by NIH R01 DE17974(Hockin HK Xu)National Science Foundation of China 81200820(to Xian-Ju Xie),81400487(to Lin Wang)+1 种基金Beijing Nova Program xx2014B060(to Xian-Ju Xie)University of Maryland School of Dentistry bridging fund(to Hockin HK Xu)
文摘White spot lesions(WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate(NACP) with long-term calcium(Ca) and phosphate(P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACPrechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release.The rechargeable cement consisted of pyromellitic glycerol dimethacrylate(PMGDM) and ethoxylated bisphenol A dimethacrylate(EBPADMA). NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength(SBS) to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release(P40.1). Specimens after one recharge treatment(e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as "1 min 3 times") exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles(P40.1). The ion re-release concentrations at 14 days versus various recharge treatments were as follows: 1 min 3 times43 min 2 times41 min 2 times46 min 1 time43 min 1 time41 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.
文摘Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties.Mg and its alloys are of poor corrosion resistance.Its high corrosion rate leads to its quick decomposition in the corrosive ambiance and as a result weakening its mechanical properties and before it is repaired,it will vanish.The corrosion and degradation rate must be controlled in the body to advance the usage of Mg and its alloys as implants.Different techniques have been utilized to boost biological properties.Plasma electrolytic oxidation(PEO)can provide porous and biocompatible coatings for implants among various techniques.Biodegradable implants are generally supposed to show enough corrosion resistance and mechanical integrity in the body environment.Much research has been carried out in order to produce PEO coatings containing calcium phosphate compounds.Calcium phosphates are really similar to bone mineral composition and present great biocompatibility.The present study deals with the usage of calcium phosphates as biocompatible coatings applied on Mg and its alloys to study the properties and control the corrosion rate.
基金the National Natural Science Foundation of China(Grant Nos.21573040 and 21603029)the Natural Science Foundation and Science and Technology Development Planning of Jilin Province(20150204086GX and20170520148JH)+3 种基金the Fundamental Research Funds for the Central Universities(2412016KJ007 and 2412016KJ020)the China Postdoctoral Science Foundation(2016M600224)the Jilin Provincial Research Foundation for Basic Research(20160519012JH)Jilin Provincial Key Laboratory of Advanced Energy Materials(Northeast Normal University)
文摘A facile strategy to fabricate gold nanorod@polyacrylic acid/calcium phosphate(Au NR@-PAA/Ca P) yolk–shell nanoparticles(NPs) composed with a PAA/Ca P shell and an Au NR yolk is reported. The asobtained Au NR@PAA/Ca P yolk–shell NPs possess ultrahigh doxorubicin(DOX) loading capability(1 mg DOX/mg NPs), superior photothermal conversion property(26%)and p H/near-infrared(NIR) dual-responsive drug delivery performance. The released DOX continuously increased due to the damage of the Ca P shell at low p H values. When the DOX-loaded Au NR@PAA/Ca P yolk–shell NPs wereexposed to NIR irradiation, a burst-like drug release occurs owing to the heat produced by the Au NRs. Furthermore,Au NR@PAA/Ca P yolk–shell NPs are successfully employed for synergic dual-mode X-ray computed tomography/photoacoustic imaging and chemo-photothermal cancer therapy. Therefore, this work brings new insights for the synthesis of multifunctional nanomaterials and extends theranostic applications.
文摘Globally,vast research interest is emerging towards the development of biodegradable orthopedic implants as it overcomes the toxicity exerted by non-degradable implants when fixed in the human body for a longer period.In this context,magnesium(Mg)plays a major role in the production of biodegradable implants owing to their characteristic degradation nature under the influence of body fluids.Also,Mg is one of the essential nutrients required to perform various metabolic activities by the human cells,and therefore,the degraded Mg products will be readily absorbed by the nearby tissues.Nevertheless,the higher corrosion rate in the biological environment is the primary downside of using Mg implants that liberate H2gas resulting in the formation of cavities.Further,in certain cases,Mg undergoes complete degradation before the healing of damaged bone tissue and cannot serve the purpose of providing mechanical support.So,many studies have been focused on the development of different strategies to improve the corrosion-resistant behavior of Mg according to the requirement.In this regard,the present review focused on the limitations of using pure Mg and Mg alloys for the fabrication of medical implants and how the calcium phosphate conversion coating alters the corrosive tendency through the formation of hydroxyapatite protective films for enhanced performance in medical implant applications.
基金This study is partly supported by the following programs:National Natural Science Foundation of China(Grant No.52035012,51372210)the Basic Research Foundation Key Project of Sichuan Province(2021JY0046)Fundamental Research Funds for the Central Universities(2682020ZT91).
文摘The aim of this study was to reconstruct surface porous structure with hundreds of micrometers and then bio-mineralize Sr-doped Calcium Phosphate(Sr-doped CaP)on Polyetheretherketone(PEEK)profile to enhance its bioactivity.A surface porous structure was prepared on PEEK profile by embedding and acid-etching of SiO2 particles as porogen(SP-PEEK).Then the Sr-doped CaP was further decorated on the porous surface after sulfonation,introduction of Sr-doped CaP crystal seeds and bio-mineralization in 1.5 times simulated body fluid(BSSP-PEEK-CaP/Sr).It was feasible to reconstruct the surface porous structure with hundreds of micrometers on PEEK profile by the present method without damaging its mechanical properties.The Sr-doped CaP crystal seeds effectively promoted the bio-mineralization of bio-inertness PEEK.All as-prepared PEEK did not inhibit the proliferation of cells.ALP of bio-mineralized groups was significantly increased than that of the other groups.The BSSP-PEEK-CaP/Sr obviously affected the morphology and promoted the adhesion and spreading of cells.As a result,the cyto-biocompatibity and bioactivity of PEEK were improved after bio-mineralization.Sr-doped CaP on PEEK most likely was beneficial for cells,which was associated with the increasing of the hydrophilicity on PEEK.This study provided a candidate method to improve the osteogenesis of PEEK implants.
文摘Perfluorocarbon emulsion has been studied as an oxygen carrier, due to its high oxygen content. In clinical trials, it has shown stability in delivering oxygen to the target region. The purpose of the present study was to increase the stability of the emulsion by coating its surface with calcium phosphate. A layer-by-layer method was employed to coat the flexible emulsion surface. Considering the ionic affinity of calcium and phosphate to the lecithin emulsion surface, the first layer of coating was calcium and the second layer was comprised of phosphate ion. The coated emulsion demonstrated various oxygen release times depending on the thickness of the layers: from 0.04 sec. for a thickness of 8 nm to 0.17 sec. for a thickness 38 nm. Overall, the stability of the calcium phosphate coated emulsion was increased, while its original function as an oxygen carrier was maintained.
基金financially supported by the National Natural Science Foundation of China (31700689)Natural Science Foundation of Shanxi Province (201901D111115)+1 种基金Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (172040098-S)Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi (2020CG015)
文摘Recently,multifunctional nanoparticles have shown great prospects in cancer treatment,which have the ability to simultaneously deliver the drug,image and target tumor cells.In this paper,we designed a luminescent nanoparticles platform based on hydrothermal hyaluronic acid/amorphous calcium phosphate(HA-FCNs/ACP)with multifunctional properties for drug delivery,bio-imaging,and targeting treatment.HA-FCNs/ACP shows an ability to load curcumin(Cur)with pH-sensitive responsive drug release behavior and excellent biocompatibility.HA-FCNs/ACP dispersed in the cytoplasm through the overexpressed CD44 receptor that is actively targeted into human lung cancer cells(A549 cells).Meanwhile,the viability of A549 cells was significantly inhibited in vitro.The prepared HA-FCNs and HA-FCNs/ACP both exhibit excellent targeted bioimaging performance on cancer cells.Hence,the as-prepared nanoparticles have promising applications in treating tumor disease.
基金National Natural Science Foundation of China(Grant No.52035012)Fundamental Research Funds for the Central Universities(2682020ZT91)+1 种基金Basic Research Foundation Key Project of Sichuan Province(2021JY0046)Basic Research Foundation of Sichuan Province(2022JDRC0088).
文摘The utilization of Calcium Phosphate Cement(CPC)is limited due to its low mechanical strength and difficulty to seed cells deep into the scaffold.The objectives of this study were to:(1)develop a 3D-printed CPC-dopamine-metformin scaffold encapsulating human periodontal ligament stem cells(hPDLSCs),(2)investigate the effect of dopamine on the performance of CPC,and(3)evaluate the effect of microbead degradation and metformin release on the osteogenic differentiation of the released hPDLSCs.The mechanical property of the CPC scaffolds was elevated by adding dopamine,and the CPC scaffold with 7 wt.%dopamine had the highest compressive strength(7.35 MPa).Four types of microbeads with different content of alginate(oxidized alginate),hPDLSCs,and 2%metformin were fabricated.Morphological and cell counting kit tests confirm that the hPDLSCs are protected by microbeads encapsulation during the CPC setting process.The alkaline phosphatase test indicates that the osteogenic differentiation of hPDLSCs was enhanced by the fast release of cells and metformin.The microbeads consisting of 2%oxidized alginate and 2%metformin were optimal for cell delivery due to favorable cell release and osteogenic differentiation.This CPC scaffold is promising used for bone regeneration in dental,craniofacial,and orthopedic applications.
文摘Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standards. A number of analytical methods are presently used for the analysis of metals in the biochemical. The instrumental techniques available are Inductively Coupled Plasma (ICP/MS), X-Ray Fluorescence, UV-VIS Spectrophotometry, and Atomic Absorption Spectrometry. Flame AA has gained widespread acceptance as an analytical technique and is used for many applications. In this study, we have determined the amount of manganese metal present in Tricalcium Phosphate (TCP) using Flame Atomic Absorption Spectrophotometer. The method has high precision and accuracy. The percent recovery was found to be 99.8% for spiked sample. The results meet the requirement.
基金supported by the Japan Society for the Promotion of Science,Grants-in-Aid for Scientific Research Fundamental Research(C)19K10161.
文摘The aim of this study was to evaluate the dentinal tubule sealing and acid resistance of dentin specimens following the application of calcium phosphate glass powder prior to irradiation with a CO2(carbon dioxide)laser.Dentin models simulating open dentinal tubules were divided into two groups:experimental(calcium phosphate glass slurry applied to the dentin surface)and control(no slurry applied to the surface).All specimens in the experimental group and five specimens in the control group were irradiated with a CO2 laser.The defocused laser beams(0.5 and 1 W)were applied(spot size,5 mm in diameter)from a distance of 20 mm for 10 s.The surfaces and cross-sectional areas of the specimens were examined using an SEM(scanning electron microscope).In addition,the resistance to acid was evaluated in these specimens.The open dentinal tubules in the control groups were sealed following irradiation with the CO2 laser at 0.5 W and 1.0 W.Likewise,sealing of open dentinal tubules was observed in the experimental group after CO2 laser irradiation.The acid resistance of the dentin surface was improved after CO2 laser irradiation;specimens in the experimental group presented with significantly lower amounts of Ca ion release compared to those in the control group.These findings indicate that CO2 laser irradiation alone or after the application of calcium phosphate glass powder can effectively seal the dentinal tubules and alleviate dentin hypersensitivity.
文摘A biphasic bone grafting biomaterial based on a mixture of calcium phosphates and beta-tricalcium phosphate (<em>β</em>-TCP) phases with high nanoporosity was synthesized. The synthesis route was based on calcium phosphate composition and the incorporation of glycolic acid as a pore former, giving a material composed of 97% <em>β</em>-TCP and 3% calcium orthophosphates (CaPO<sub>4</sub>). An<em> i</em><em></em><span></span><em>n </em><em>vitro</em> study of the purity, microstructure, crystalline domain, and pores size for the material obtained was performed by SEM analysis as well as full structural characterization. The region of interest related to the surface was determined by the specific surface area measured with the BET method. <em>In vivo</em> evaluation of bone response was performed by implanting the new low-cost biphasic manufacturing material synthesized in this work, which was compared with a biphasic material of similar chemical and microstructural composition existing in the commercial market and with higher cost called Synergy Odontit<sup><span style="white-space:nowrap;">®</span></sup> <em>β</em>-TCP. The materials were implanted separately into 5 mm diameter defects in the tibias of New Zealand White rabbits at 30, 60, and 90 days. The results obtained showed that the host tissue well accepted the new biphasic material;the presence of new bone formation was observed. A more complete resorption was observed for the new microcrystalline biphasic material compared to for a commercial <em>β</em>-TCP material.
基金Funded by the National Natural Science Foundation of China(51772233)the Key Basic Research Program of Shenzhen(No.JCYJ20200109150218836)。
文摘The synthesis of mesoporous β-tricalcium phosphate(β-TCP)powder was performed by using the microemulsion approach,with hexadecyltrimethyl ammonium bromide(CTAB)/cyclohexane/n-octyl alcohol microemulsion system.The influences of different pH values and calcination temperatures on the phase composition of the β-TCP powder were studied.The in vitro proliferation of bone marrow mesenchymal stem cells(BMSCs)in the suspensions of β-TCP powders with meso-structure was studied.The phase composition,mesoporous structure,powder morphology,cell morphology and the optical density(OD)were characterized through X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),Fourier transform infrared(FTIR)spectroscopy,Nadsorption-desorption isotherms,inverted phase contrast microscopy and Multiskan spectrum,respectively.The mesoporous β-TCP powder with specific surface area of 12.85 m^(2)/g and the average pore size 7.11 nm was obtained through the microemulsion approach(100 g/L CTAB/250 mL/L cyclohexane/250 mL/L n-octyl alcohol)with a controlled pH of 7.0,after calcinating the powder at 800℃.It was confirmed that mesoporous β-TCP powder benefits the activity of BMSCs more than the non-mesoporous β-TCP powder.
文摘In this work wollastonite/tricalcium phosphate (W/TCP) glass-ceramics with three W/TCP weight ratios (20/80;60/40 and 80/20) were implanted in rat calvaria and the modifications taking place during implantation were studied by Raman spectroscopy. The experimental glass-ceramics were composed of different contents of βW, αW, βTCP, αTCP, and glassy phases. Materials were implanted for 7-, 15-, 45- and 120-day periods after which the implanted materials were recovered and analyzed by FT-Raman spectroscopy. The results suggested that the αW phase reabsorbs fast during implantation in the glass-ceramics 60/40 and 80/20, whereas βTCP and αTCP glass-ceramic are gradually attenuated and replaced by biological apatite-like bands. In the glass-ceramic 20/80, the bands related to the βTCP phase remained unvaried in all analyzed periods. New bands associated with the deposition of collagenous material appeared during implantation for all 60/40 and 80/20 glass-ceramics experimental groups, but important differences in intensities between both groups. The spectra corresponding to implants of 60/40 glass-ceramic at the 120-day period were very similar to those of the control group (normal cortical bone), with regards to Raman shifts and intensities, as well as in the FWHM value of the 962 cm<sup>-1</sup> apatite band (ν1 PO4 in hydroxyapatite), evidencing that apatite deposited at the implant site has the same crystallinity than biological apatite in normal bone mineral. The glass-ceramic 20/80 behaved just as an osteoconductive filling material, while glass-ceramics 60/40 and 80/20 were able to induce deposition of organic matrix mineralized new tissue. The 60/40 glass-ceramic showed the best performance and the most similar Raman spectrum to normal cortical bone.
基金supported by NIH R01 DE14190 and R21 DE22625(HX)the National Science Foundation of China 81401794(PW)and 81400487(LW)+2 种基金the Youth Fund of Science and Technology of Jilin Province 20150520043JH(LW)the China Postdoctoral Science Foundation 2015M581405(LW)the University of Maryland School of Dentistry bridge fund(HX)
文摘Calcium phosphate cements(CPCs) are frequently used to repair bone defects. Since their discovery in the 1980 s, extensive research has been conducted to improve their properties, and emerging evidence supports their increased application in bone tissue engineering. Much effort has been made to enhance the biological performance of CPCs, including their biocompatibility, osteoconductivity, osteoinductivity, biodegradability,bioactivity, and interactions with cells. This review article focuses on the major recent developments in CPCs,including 3 D printing, injectability, stem cell delivery, growth factor and drug delivery, and prevascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.
基金Supported by Grant-in-Aid for Young Scientists(KAKENHI)
文摘AIM: To determine the effects of transplanting osteogenic matrix cell sheets and beta-tricalcium phosphate(TCP) constructs on bone formation in bone defects.METHODS: Osteogenic matrix cell sheets were prepared from bone marrow stromal cells(BMSCs), and a porous TCP ceramic was used as a scaffold. Three experimental groups were prepared, comprised of TCP scaffolds(1) seeded with BMSCs;(2) wrapped with osteogenic matrix cell sheets; or(3) both. Constructs were implanted into a femoral defect model in rats and bone growth was evaluated by radiography, histology, biochemistry, and mechanical testing after 8 wk. RESULTS: In bone defects, constructs implanted with cell sheets showed callus formation with segmentalor continuous bone formation at 8 wk, in contrast to TCP seeded with BMSCs, which resulted in bone nonunion. Wrapping TCP constructs with osteogenic matrix cell sheets increased their osteogenic potential and resulting bone formation, compared with conventional bone tissue engineering TCP scaffolds seeded with BMSCs. The compressive stiffness(mean ± SD) values were 225.0 ± 95.7, 30.0 ± 11.5, and 26.3 ± 10.6 MPa for BMSC/TCP/Sheet constructs with continuous bone formation, BMSC/TCP/Sheet constructs with segmental bone formation, and BMSC/TCP constructs, respectively. The compressive stiffness of BMSC/TCP/Sheet constructs with continuous bone formation was significantly higher than those with segmental bone formation and BMSC/TCP constructs.CONCLUSION: This technique is an improvement over current methods, such as TCP substitution, and is useful for hard tissue reconstruction and inducing earlier bone union in defects.
基金supported by National Natural Science Foundation of China (81670977, J.L. and 81800965, K.L.)Sichuan Science and Technology program (Grant no. 2017SZ0030)+5 种基金Fundamental Research Funds for Central University 2018SCU12016 (K.L.)China Postdoctoral Science Grant 2018M643507 (K.L.)Research Fund of West China Hospital WCHS-201705 (K.L.)Research Fund for Resins of Chinese Stomatological Association CSA-R2018-06 (K.L.)University of Maryland School of Dentistry bridging fund (H.H.K.X.)University of Maryland Baltimore seed grant (H.H.K.X.)
文摘Tooth decay is prevalent,and secondary caries causes restoration failures,both of which are related to demineralization.There is an urgent need to develop new therapeutic materials with remineralization functions.This article represents the first review on the cutting edge research of poly(amido amine)(PAMAM) in combination with nanoparticles of amorphous calcium phosphate (NACP).PAMAM was excellent nucleation template,and could absorb calcium (Ca) and phosphate (P) ions via its functional groups to activate remineralization.NACP composite and adhesive showed acid-neutralization and Ca and P ion release capabilities.PAMAM +NACP together showed synergistic effects and produced triple benefits: excellent nucleation templates,superior acidneutralization,and ions release.Therefore,the PAMAM+NACP strategy possessed much greater remineralization capacity than using PAMAM or NACP alone.PAMAM+NACP achieved dentin remineralization even in an acidic solution without any initial Ca and P ions.Besides,the long-term remineralization capability of PAMAM+NACP was established.After prolonged fluid challenge,the immersed PAMAM with the recharged NACP still induced effective dentin mineral regeneration.Furthermore,the hardness of predemineralized dentin was increased back to that of healthy dentin,indicating a complete remineralization.Therefore,the novel PAMAM+NACP approach is promising to provide long-term therapeutic effects including tooth remineralization,hardness increase,and caries-inhibition capabilities.
基金This work was supported by the National Key Research and Development Program of China(No.18YFB1105600,2018YFC1106800)National Natural Science Foundation of China(51875518)+1 种基金Sichuan Province Science&Technology Department Projects(2016CZYD0004,2017SZ0001,2018GZ0142,2019YFH0079)Research Foundation for Young Teachers of Sichuan University(2018SCUH0017)and The“111”Project(No.B16033).
文摘The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone regeneration.Physicochemical properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect repair.Histological results indicated that the 3DS was highly vascularized and well combined with surrounding tissues.FS showed obvious newly formed bone tissues.AB showed the best repair effect,but it was found that AB scaffolds were partially absorbed and degraded.This study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.
基金The project was financially supported by the National Natural Science Foundation of China (No. 20174018).
文摘Phosphorylated chitins (P-chitins) as the additives of calcium phosphate cements (CPCs) were prepared by thephosphorylation of chitin with phosphorus pentoxide in methanesulfonic acid. Their physical properties and effects on CPCsfrom monocalcium phosphate monohydrate (MCPM) and calcium oxide (CaO) or dicalcium phosphate dihydrate (DCPD)and calcium hydroxide [Ca(OH)2] were investigated. Addition of P-chitin (Mw = 2.60 x 104; degree of substitution, DS =0.68)to the liquid phase in amounts up to 3 wt% for MCPM and CaO cements or 1.5 wt% for DCPD and Ca(OH)2 cementscould enhance the mechanical strength considerably, while little influence on the setting time was observed. However, furtheraddition of P-chitin will cause no setting.
文摘The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with an electrochemical work-station supplying a direct current power at potential of -0.8V （vs SCE）. The electrolyte consists of 7 mmol·L-1 CaCl2·2H2O, 3 mmol·L-1 Ca（H2PO4）2·H2O and 2.5% H2O2. NaOH and HCl solutions were used to adjust pH value. The deposited samples were characterized by X-ray diffraction and scanning electron microscope. The comparison of the deposits obtained at lower and higher pH values demonstrates that the crystallization process at the interface is favoured by high pH value. With temperature increasing, the deposited hydroxyapatite is occasionally of plate-like shape, and the width and the length of the deposited calcium phosphates at 65 ℃ are larger than those at 55 ℃. Therefore, it is confirmed that the morphology and microstructure of electrochemically deposited calcium phosphates can be regulated. Additionally, the coating formed in electrolyte with H2O2 additive is homogeneous and the evolution of H2 bubble can be eliminated.
