Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.881
Filtrar
1.
Int J Nanomedicine ; 16: 147-159, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33456309

RESUMO

Background: There is still a big challenge to achieve a balance between mechanical characteristics and biological properties in biphasic calcium phosphate (BCP) ceramics. Purpose: The present study focused on the in-situ whisker growth on BCP ceramics via different hydrothermal treatments and investigated the influences of these whiskers on the mechanical property and biological performance of the ceramics. Methods: Five kinds of BCP ceramics with in-situ whisker growth, ie, BCP-C, BCP-HNO3, BCP-Citric, BCP-NaOH, BCP-CaCl2 and BCP-Na3PO4 were fabricated by different hydrothermal treatments. The phase compositions, morphologies, crystal structures and mechanical strengths of the obtained BCP ceramics were firstly characterized. Then, the in vitro cell adhesion, proliferation and alkaline  phosphatase (ALP) activity of bone marrow stromal cells (BMSCs) on the BCP ceramics were evaluated. Lastly, the effects of in-situ whisker growth on the bone-like apatite formation abilities of BCP ceramics were also investigated by immersing them in simulated body fluid (SBF). Results: The results demonstrated that the hydrothermal conditions, especially the hydrothermal media, were crucial to determine the phase composition and morphology of the in-situ whisker. Especially among the five media used (HNO3, Citric, NaOH, CaCl2 and Na3PO4), the Na3PO4 treatment resulted in the shortest whisker with a unique hollow structure, and kept the original biphasic composition. All five kinds of whiskers increased the mechanical strength of BCP ceramics to some extent, and showed the good ability of bone-like apatite formation. The in vitro cell study demonstrated that the in-situ whisker growth had no adverse but even positive effect on the adhesion, proliferation and ALP activity of BMSCs. Conclusion: Due to the growth of in-situ whiskers, the mechanical property and biological performance of the obtained BCP ceramics could increase simultaneously. Therefore, in-situ whiskers growth offers a promising strategy for the expanded application of BCP ceramics to meet the requirements of regenerative medicine.


Assuntos
Fosfatos de Cálcio/química , Cerâmica/química , Temperatura , Água/química , Fosfatase Alcalina/metabolismo , Animais , Apatitas/metabolismo , Adesão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Teste de Materiais , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/ultraestrutura , Camundongos , Osteogênese/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
2.
PLoS One ; 15(8): e0238055, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845898

RESUMO

Lodgepole pine, a prominent Pinaceae tree species native to western North America, is well-known for its ability to thrive in highly disturbed and degraded areas. One such area is the Sub-Boreal Pine-Spruce xeric-cold (SBPSxc) region in British Columbia, Canada, which is characterized by weakly-developed, parched soils that lack an organic forest floor and essential plant-available nutrients. We hypothesized that plant growth-promoting bacteria could play a significant role in sustaining the growth of lodgepole pine trees in the SBPSxc region. Testing this hypothesis, we evaluated plant growth-promoting abilities of six endophytic bacterial strains previously isolated from lodgepole pine trees growing in this region. These bacterial strains significantly enhanced the length and biomass of their natural host (lodgepole pine) as well as a foreign host (hybrid white spruce) in a 540-day long greenhouse trial. This growth stimulation could be linked to the diverse plant growth-promoting (PGP) abilities detected in these strains using in vitro assays for inorganic/organic phosphate-solubilization, siderophore production IAA production, ACC deaminase activity, lytic enzymes (chitinase, ß-1,3-glucanase, protease, and cellulase) activity, ammonia production and catalase activity. ACC deaminase activity was also detected in vivo for all strains using ethylene-sensitive plants-canola and tomato. Notably, strains belonging to the Burkholderiaceae family (HP-S1r, LP-R1r and LP-R2r) showed the greatest potential in all PGP assays and enhanced pine and spruce seedling length and biomass by up to 1.5-fold and 4-fold, respectively. Therefore, such bacterial strains with multifarious PGP abilities could be crucial for survival and growth of lodgepole pine trees in the SBPSxc region and could potentially be utilized as bioinoculant for Pinaceae trees in highly disturbed and nutrient-poor ecosystems.


Assuntos
Bactérias/isolamento & purificação , Pinaceae/crescimento & desenvolvimento , Biomassa , Fosfatos de Cálcio/química , Fosfatos de Cálcio/metabolismo , Carbono-Carbono Liases/genética , Carbono-Carbono Liases/metabolismo , Ecossistema , Etilenos/metabolismo , Ácidos Indolacéticos/metabolismo , Picea/crescimento & desenvolvimento , Picea/metabolismo , Picea/microbiologia , Pinaceae/metabolismo , Pinaceae/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/microbiologia , Plântula/fisiologia , Sideróforos/metabolismo
3.
Int J Nanomedicine ; 15: 5561-5571, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801704

RESUMO

Purpose: Platinum/paclitaxel-based chemotherapy is the strategy for ovarian cancer, but chemoresistance, inherent or acquired, occurs and hinders therapy. Therefore, further understanding of the mechanisms of drug resistance and adoption of novel therapeutic strategies are urgently needed. Methods: In this study, we report that sphingosine-1-phosphate receptor-1 (S1PR1)-mediated chemoresistance for ovarian cancer. Then we developed nanoparticles with a hydrophilic PEG2000 chain and a hydrophobic DSPE and biodegradable CaP (calcium ions and phosphate ions) shell with pH sensitivity as a delivery system (CaP-NPs) to carry BAF312, a selective antagonist of S1PR1 (BAF312@CaP-NPs), to overcome the cisplatin (DDP) resistance of the ovarian cancer cell line SKOV3DR. Results: We found that S1PR1 affected acquired chemoresistance in ovarian cancer by increasing the phosphorylated-signal transduction and activators of transcription 3 (P-STAT3) level. The mean size and zeta potential of BAF312@CaP-NPs were 116 ± 4.341 nm and -9.67 ± 0.935 mV, respectively. The incorporation efficiency for BAF312 in the CaP-NPs was 76.1%. The small size of the nanoparticles elevated their enrichment in the tumor, and the degradable CaP shell with smart pH sensitivity of the BAF312@CaP-NPs ensured the release of BAF312 in the acidic tumor niche. BAF312@CaP-NPs caused substantial cytotoxicity in DDP-resistant ovarian cancer cells by downregulating S1PR1 and P-STAT3 levels. Conclusion: We found that BAF312@CaP-NPs act as an effective and selective delivery system for overcoming S1PR1-mediated chemoresistance in ovarian carcinoma by inhibiting S1PR1 and P-STAT3.


Assuntos
Azetidinas/administração & dosagem , Compostos de Benzil/administração & dosagem , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Nanopartículas/química , Neoplasias Ovarianas/tratamento farmacológico , Fator de Transcrição STAT3/antagonistas & inibidores , Receptores de Esfingosina-1-Fosfato/genética , Azetidinas/farmacocinética , Compostos de Benzil/farmacocinética , Fosfatos de Cálcio/química , Linhagem Celular Tumoral , Cisplatino/uso terapêutico , Sistemas de Liberação de Medicamentos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Fosforilação/efeitos dos fármacos , Polietilenoglicóis/química , Fator de Transcrição STAT3/metabolismo , Receptores de Esfingosina-1-Fosfato/antagonistas & inibidores , Receptores de Esfingosina-1-Fosfato/metabolismo
4.
PLoS Comput Biol ; 16(7): e1007996, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32667909

RESUMO

Cortical spreading depression (CSD) is the propagation of a relatively slow wave in cortical brain tissue that is linked to a number of pathological conditions such as stroke and migraine. Most of the existing literature investigates the dynamics of short term phenomena such as the depolarization and repolarization of membrane potentials or large ion shifts. Here, we focus on the clinically-relevant hour-long state of neurovascular malfunction in the wake of CSDs. This dysfunctional state involves widespread vasoconstriction and a general disruption of neurovascular coupling. We demonstrate, using a mathematical model, that dissolution of calcium that has aggregated within the mitochondria of vascular smooth muscle cells can drive an hour-long disruption. We model the rate of calcium clearance as well as the dynamical implications on overall blood flow. Based on reaction stoichiometry, we quantify a possible impact of calcium phosphate dissolution on the maintenance of F0F1-ATP synthase activity.


Assuntos
Depressão Alastrante da Atividade Elétrica Cortical , Potenciais da Membrana , Mitocôndrias/metabolismo , Vasoconstrição , Trifosfato de Adenosina/química , Cálcio/química , Fosfatos de Cálcio/química , Córtex Cerebral/fisiopatologia , Circulação Cerebrovascular , Citosol/química , Retículo Endoplasmático/química , Substância Cinzenta/fisiopatologia , Humanos , Modelos Teóricos , Acoplamento Neurovascular , Oscilometria , Oxigênio/química , Fosforilação , ATPases Translocadoras de Prótons/química , Acidente Vascular Cerebral/fisiopatologia
5.
Phys Chem Chem Phys ; 22(23): 13108-13117, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32490501

RESUMO

Adenosine triphosphate (ATP) biomolecules play critial roles in the biomineralization process during the formation of amorphous calcium phosphate composites (ACPC), and ACPC is an important drug carrier due to its significant advantages of biocompatibility and biodegradability. Hence, studying the behavior of ACPC nanodrug carriers is crucial to investigate the structural regulation of biomimetic minerals and calcium phosphate (CaP)-based drug delivery systems. However, it is difficult to probe these interactions using traditional characterization methods. In this paper, XANES analysis together with STXM successfully provided a method to reveal the interaction of ATP and drug molecules with individual mesoporous ACPC. We found that the adenosine and phosphate groups of ATP biomolecules coordinated with Ca2+ and played critical roles in the formation of ACPC; drug molecules with the -COOH groups were linked to Ca2+via carboxylic acid groups primarily by electrostatic interactions, and the N-containing ring structures within the drug molecules also coordinated with Ca2+.


Assuntos
Trifosfato de Adenosina/química , Fosfatos de Cálcio/química , Doxorrubicina/química , Nanocompostos/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Hemoglobinas/química , Tamanho da Partícula , Porosidade , Propriedades de Superfície , Espectroscopia por Absorção de Raios X
6.
PLoS One ; 15(6): e0234216, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32492072

RESUMO

The role of root exudates has long been recognized for its potential to improve nutrient use efficiency in cropping systems. However, studies addressing the variability of root exudates involved in phosphorus solubilization across plant developmental stages remain scarce. Here, we grew Arabidopsis thaliana seedlings in sterile liquid culture with a low, medium, or high concentration of phosphate and measured the composition of the root exudate at seedling, vegetative, and bolting stages. The exudates changed in response to the incremental addition of phosphorus, starting from the vegetative stage. Specific metabolites decreased in relation to phosphate concentration supplementation at specific stages of development. Some of those metabolites were tested for their phosphate solubilizing activity, and 3-hydroxypropionic acid, malic acid, and nicotinic acid were able to solubilize calcium phosphate from both solid and liquid media. In summary, our data suggest that plants can release distinct compounds to deal with phosphorus deficiency needs influenced by the phosphorus nutritional status at varying developmental stages.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Fósforo/metabolismo , Exsudatos de Plantas/metabolismo , Raízes de Plantas/metabolismo , Fosfatos de Cálcio/química , Fosfatos de Cálcio/metabolismo , Fertilizantes , Fosfatos/farmacocinética , Exsudatos de Plantas/análise , Solubilidade
7.
Int J Nanomedicine ; 15: 3729-3740, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547025

RESUMO

Background: Duraplasty is one of the most critical issues in neurosurgical procedures because the defect of dura matter will cause many complications. Electrospinning can mimic the 3D structure of the natural extracellular matrix whose structure is similar to that of dura matter. Poly(L-lactic acid) (PLLA) has been used to fabricate dura matter substitutes and showed compatibility to dural tissue. However, the mechanical properties of the PLLA substitute cannot match the mechanical properties of the human dura mater. Methods and Results: We prepared stereocomplex nanofiber membranes based on enantiomeric poly(lactic acid) and poly(D-lactic acid)-grafted tetracalcium phosphate via electrospinning. X-ray diffraction results showed the formation of stereocomplex crystallites (SC) in the composite nanofiber membranes. Scanning electron microscope observation images showed that composites nanofibers with higher SC formation can keep its original morphologies after heat treatment, suggesting the heat resistance of composite nanofiber membranes. Differential scanning calorimeter tests confirmed that the melting temperature of composite nanofiber membranes was approximately 222°C, higher than that of PLLA. Tensile testing indicated that the ultimate tensile strength and the elongation break of the stereocomplex nanofiber membranes were close to human dura matter. In vitro cytotoxicity studies proved that the stereocomplex nanofiber membranes were non-toxic. The neuron-like differentiation of marrow stem cells on the stereocomplex nanofiber membranes indicated its neuron compatibility. Conclusion: The stereocomplex nanofiber membranes have the potential to serve as a dura mater substitute.


Assuntos
Materiais Biomiméticos/química , Dura-Máter/fisiologia , Nanofibras/química , Poliésteres/química , Animais , Fosfatos de Cálcio/química , Varredura Diferencial de Calorimetria , Diferenciação Celular , Linhagem Celular , Cristalização , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Camundongos , Nanofibras/ultraestrutura , Neurônios/citologia , Ratos Sprague-Dawley , Estereoisomerismo , Temperatura , Difração de Raios X
8.
Int J Nanomedicine ; 15: 3877-3886, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32581535

RESUMO

Introduction: Vaccine formulation with appropriate adjuvants is an attractive approach to develop protective immunity against pathogens. Calcium phosphate nanoparticles (CaPNs) are considered as ideal adjuvants and delivery systems because of their great potential for enhancing immune responses. In the current study, we have designed nanoparticle-based vaccine candidates to induce immune responses and protection against B. melitensis and B. abortus. Materials and Methods: For this purpose, we used three Brucella antigens (FliC, 7α-HSDH, BhuA) and two multi-epitopes (poly B and poly T) absorbed by CaPNs. The efficacy of each formulation was evaluated by measuring humoral, cellular and protective responses in immunized mice. Results: The CaPNs showed an average size of about 90 nm with spherical shape and smooth surface. The CaPNs-adsorbed proteins displayed significant increase in cellular and humoral immune responses compared to the control groups. In addition, our results showed increased ratio of specific IgG2a (associated with Th1) to specific IgG1 (associated with Th2). Also, immunized mice with different vaccine candidate formulations were protected against B. melitensis 16M and B. abortus 544, and showed same levels of protection as commercial vaccines (B. melitensis Rev.1 and B. abortus RB51) except for BhuA-CaPNs. Discussion: Our data support the hypothesis that these antigens absorbed with CaPNs could be effective vaccine candidates against B. melitensis and B. abortus.


Assuntos
Antígenos de Bactérias/química , Vacina contra Brucelose/química , Vacina contra Brucelose/imunologia , Nanopartículas/química , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/farmacologia , Animais , Proteínas de Bactérias/imunologia , Brucella abortus/imunologia , Brucella melitensis/imunologia , Brucelose/imunologia , Brucelose/prevenção & controle , Fosfatos de Cálcio/química , Sistemas de Liberação de Medicamentos , Feminino , Imunidade Humoral , Imunização , Imunoglobulina G/imunologia , Proteínas de Membrana Transportadoras/imunologia , Camundongos Endogâmicos BALB C
9.
Sci Rep ; 10(1): 4979, 2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-32188900

RESUMO

It has been demonstrated that development of three-dimensional printing technology has supported the researchers and surgeons to apply the bone tissue engineering to the oromandibular reconstruction. In this study, poly caprolactone/beta tricalcium phosphate (PCL/ß-TCP) scaffolds were fabricated by multi-head deposition system. The feasibility of the three-dimensionally (3D) -printed PCL/ß-TCP scaffolds for mandibular reconstruction was examined on critical-sized defect of canine mandible. The scaffold contained the heterogeneous pore sizes for more effective bone ingrowth and additional wing structures for more stable fixation. They were implanted into the mandibular critical-sized defect of which periosteum was bicortically resected. With eight 1-year-old male beagle dogs, experimental groups were divided into 4 groups (n = 4 defects per group, respectively). (a) no further treatment (control), (b) PCL/ß-TCP scaffold alone (PCL/TCP), (c) PCL/ß-TCP scaffold with recombinant human bone morphogenetic protein-2 (rhBMP-2) (PCL/TCP/BMP2) and (d) PCL/ß-TCP scaffold with autogenous bone particles (PCL/TCP/ABP). In micro-computed tomography, PCL/TCP/BMP2 and PCL/TCP/ ABP groups showed significant higher bone volume in comparison to Control and PCL/TCP groups (P < 0.05). In histomorphometric analysis, a trend towards more bone formation was observed in PCL/TCP/BMP2 and PCL/TCP/ABP groups, but the results lacked statistical significance (P = 0.052). Within the limitations of the present study, 3D-printed PCL/ß-TCP scaffolds showed acceptable potential for oromandibular reconstruction.


Assuntos
Fosfatos de Cálcio/química , Mandíbula/citologia , Mandíbula/cirurgia , Reconstrução Mandibular/métodos , Poliésteres/química , Impressão Tridimensional/instrumentação , Engenharia Tecidual , Animais , Proteína Morfogenética Óssea 2/metabolismo , Regeneração Óssea , Cães , Masculino , Mandíbula/metabolismo , Proteínas Recombinantes/metabolismo , Tecidos Suporte , Fator de Crescimento Transformador beta/metabolismo
10.
PLoS One ; 15(3): e0230533, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32182267

RESUMO

As part of a verification model of antibiotic therapy in cranioplasty, we evaluated the impregnation efficiency of interporous calcium phosphate materials with saline under atmospheric pressure and compared it to the efficiency of using the decompression method established by the Japanese Industrial Standard, under which pressure is reduced by 10 kPa. Five types of material formed in 1 mL cubes were selected as test samples: two consisting of hydroxyapatite (HAp) with 85% and 55% porosity and three of ß-tricalcium phosphate (ß-TCP) with 75%, 67%, and 57% porosity. All test samples showed an impregnation ratio of more than 70%, except for the HAp sample with 55% porosity, which had a ratio of approximately 50%. These high ratios were achieved at only 15 min. The impregnation effects were likely dependent on porosity and were independent of base material, either HAp or ß-TCP. Obtaining sufficient impregnation and antimicrobial efficacy in materials with low porosity, which are commonly used in cranioplasty, would require an increased volume of antibiotics rather than increased duration of impregnation. Our findings will enable the simple preparation of drug-impregnated calcium phosphate materials, even in operating rooms not equipped with a large decompression device.


Assuntos
Antibacterianos/uso terapêutico , Materiais Biocompatíveis/química , Fosfatos de Cálcio/química , Durapatita/química , Pressão Atmosférica , Modelos Teóricos , Porosidade
11.
J Dairy Sci ; 103(5): 3971-3979, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32171507

RESUMO

We investigated the applicability of cryo-electron tomography as a method to quantify changes in the major constituents of casein micelles (i.e., casein proteins, putative colloidal calcium phosphate nanoclusters, and serum-filled voids and channels) in response to their environment. Skim milk diluted 20-fold in milk serum was used for this study. Tomograms were generated for multiple casein micelles at 2 different pH values (6.7 and 6.0) and pixel intensity thresholds were identified for each constituent. The volume of each constituent was determined using these thresholds and expressed as a fraction of micelle volume. At the given dilution, a significant decrease in the volume fractions of casein proteins (∼37%) and putative colloidal calcium phosphate nanoclusters (∼67%) was observed with the reduction of pH from 6.7 to 6.0. Assessment of casein micelle fraction obtained by ultracentrifugation of corresponding skim milk samples produced comparable results. When using such an approach, the imaging conditions, denoising methods, and thresholding approaches used can all affect the precision of the measurements, but the overall trends in constituent volumes are able to be tracked. The primary advantage of using cryo-electron tomography is that analysis can be done at the level of individual micelles, within a 3-dimensional morphological context. This workflow paves the way for high-throughput exploration of milk micelles and how their environment shapes their composition and structure.


Assuntos
Caseínas/química , Bovinos , Tomografia com Microscopia Eletrônica , Micelas , Leite/química , Animais , Fosfatos de Cálcio/química , Concentração de Íons de Hidrogênio , Ultracentrifugação
12.
Curr Med Sci ; 40(1): 155-167, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32166678

RESUMO

Bone and teeth are derived from intrafibrillarly mineralized collagen fibrils as the second level of hierarchy. According to polymer-induced liquid-precursor process, using amorphous calcium phosphate precursor (ACP) is able to achieve intrafibrillar mineralization in the case of bone biomineral in vitro. Therefore, ACP precursors might be blended with any osteoconductive scaffold as a promising bone formation supplement for in-situ remineralization of collagens in bone. In this study, mesoporous silica nanoparticles with carboxyl-functionalized groups and ultra large-pores have been synthesized and used for the delivery of liquid like biomimetic precursors (ACP). The precursor delivery capacity of the nanoparticles was verified by the precursor release profile and successful mineralization of 2D and 3D collagen models. The nanoparticles could be completely degraded in 60 days and exhibited good biocompatibility as well. The successful translational strategy for biomineralization precursors showed that biomineralization precursor laden ultra large pore mesoporous silica possessed the potential as a versatile supplement in demineralized bone formation through the induction of intrafibrillar collagen mineralization.


Assuntos
Fosfatos de Cálcio/farmacologia , Colágeno/química , Células-Tronco Mesenquimais/citologia , Dióxido de Silício/química , Animais , Biomineralização/efeitos dos fármacos , Fosfatos de Cálcio/química , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Colágeno/efeitos dos fármacos , Feminino , Células-Tronco Mesenquimais/química , Células-Tronco Mesenquimais/efeitos dos fármacos , Nanopartículas , Porosidade , Ratos
13.
Nat Commun ; 11(1): 1546, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32210234

RESUMO

Calcium orthophosphates (CaPs) are important in geology, biomineralization, animal metabolism and biomedicine, and constitute a structurally and chemically diverse class of minerals. In the case of dicalcium phosphates, ever since brushite (CaHPO4·2H2O, dicalcium phosphate dihydrate, DCPD) and monetite (CaHPO4, dicalcium phosphate, DCP) were first described in 19th century, the form with intermediary chemical formula CaHPO4·H2O (dicalcium phosphate monohydrate, DCPM) has remained elusive. Here, we report the synthesis and crystal structure determination of DCPM. This form of CaP is found to crystallize from amorphous calcium hydrogen phosphate (ACHP) in water-poor environments. The crystal structure of DCPM is determined to show a layered structure with a monoclinic symmetry. DCPM is metastable in water, but can be stabilized by organics, and has a higher alkalinity than DCP and DCPD. This study serves as an inspiration for the future exploration of DCPM's potential role in biomineralization, or biomedical applications.


Assuntos
Biomineralização , Fosfatos de Cálcio/química , Animais , Linhagem Celular , Cristalização , Células-Tronco Mesenquimais , Metanol/química , Simulação de Dinâmica Molecular , Ratos , Solventes/química , Água/química , Difração de Raios X
14.
Sci Rep ; 10(1): 4013, 2020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32132636

RESUMO

The calcium phosphate particles can be used as building blocks for fabrication of 3D scaffolds intended for bone tissue engineering. This work presents for the first time a rapid creation of 3D scaffolds using magnetic levitation of calcium phosphate particles. Namely, tricalcium phosphate particles of equal size and certain porosity are used, which undergo the process of recrystallization after magnetic levitational assembly of the scaffold to ensure stitching of the scaffold. Label-free levitational assembly is achieved by using a custom-designed magnetic system in the presence of gadolinium salts, which allows the levitation of calcium phosphate particles. Chemical transformation of tricalcium- to octacalcium phosphate under the condition of magnetic levitation in non-homogeneous magnetic field is also demonstrated. This approach allows obtaining rapidly the octacalcium phosphate phase in the final 3D product, which is biocompatible.


Assuntos
Regeneração Óssea , Osso e Ossos/metabolismo , Fosfatos de Cálcio/química , Campos Magnéticos , Impressão Tridimensional , Tecidos Suporte/química , Osso e Ossos/citologia , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Porosidade
15.
Chemosphere ; 251: 126335, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32145573

RESUMO

Pyrolysis of biomass with phosphate compound is a promising method to improve biochar characteristics. However, how phosphate compound affects the three components of biomass during the biochar formation is still unclear. In this study, a typical phosphate compound, calcium dihydrogen phosphate (Ca(H2PO4)2), was premixed with cellulose, hemicellulose, and lignin reagent, at the ratio of 20% (w/w) for biochar production through pyrolysis, aiming to investigate the effects of Ca(H2PO4)2 addition on biochar formation. Results show that, with Ca(H2PO4)2 additions, carbon retention of biochars from cellulose (MCBC) and hemicellulose (MHBC) increased by 63.4% and 48.3%, respectively, but that of lignin (MLBC) decreased by 6.7% due to the reactions between lignin and Ca(H2PO4)2. Moreover, the stable carbon proportion in the biochar decreased by 10.2% for MCBC, almost unchanged for MHBC, and increased by 6.15% for MLBC based on the potassium dichromate oxidation. During the pyrolysis process, Ca(H2PO4)2 addition fixed more volatile and/or labile carbon in biochar, resulting in greater carbon retention. Declined carbon stability of biochar might be caused by the inhibited formation of aromatic-C, evidenced by the Fourier transform infrared spectroscopy analysis. This study highlights the importance and potential mechanisms of calcium dihydrogen phosphate influencing the carbon retention and stability of biochar derived from three biomass components.


Assuntos
Fosfatos de Cálcio/química , Carvão Vegetal/química , Biomassa , Cálcio , Carbono/química , Sequestro de Carbono , Celulose/química , Lignina/química , Polissacarídeos/química , Espectroscopia de Infravermelho com Transformada de Fourier
16.
J Bone Miner Metab ; 38(4): 456-468, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32008099

RESUMO

INTRODUCTION: The goal is to propose a material scientific hypothesis for the atomic arrangement of calcium phosphates during the mineralization of bones. MATERIALS AND METHODS: It was reached by the analysis of bones of healthy and osteoporotic rats using analytical transmission electron microscopic methods. RESULTS: Electron diffraction patterns show hydroxyapatite (HAP) as dominant phase within the mineralized areas. In the electron energy loss spectrum, a double peak of the phosphorous L-edge seems to be a characteristic feature of the phosphorous binding in biological HAP. The hypothesis bases on periodic features on the collagen surface which agree with distances between oxygen atoms in the (200) plane of octacalcium phosphate (OCP). Bridge pillars for the HAP network consist of OCP coupled with a half unit cell on collagen by oxygen-hydrogen bridges. Possibly, the metastable OCP bridges are only a transient step, while the mineralization is starting. OCP and HAP couple by similar distances of calcium atoms in an interface close to the (100) planes of the OCP and the HAP network. To reach the perfect overlap of the equidistant Ca atoms, the HAP network has to be rotated by 22.5° around the a-axis, 11.5° around the c-axis of HAP, and 10.1° around an axis perpendicular to a and c. CONCLUSIONS: A supercell based on this idea is able to explain the dominance of HAP in the electron diffraction patterns, the arrangement of the (002) lattice planes perpendicular to the collagen fiber axis, and sections of high-resolution TEM images.


Assuntos
Biomineralização/fisiologia , Osso e Ossos/fisiologia , Animais , Osso e Ossos/ultraestrutura , Fosfatos de Cálcio/química , Durapatita/química , Feminino , Minerais/química , Ratos Sprague-Dawley , Difração de Raios X
17.
Int J Nanomedicine ; 15: 433-444, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32021189

RESUMO

Background: Carbon dots (CDs) have attracted extensive attention in recent years because of their high biocompatibility and unique optical property. But they could not be well applied in the drug delivery system to enable distribution in tumor sites with their low pH sensitivity. They are barriers for drug delivery. CDs as an imaging proper were conjugated with doxorubicin (DOX) lipid-coated calcium phosphate (LCP) nanoparticle, for a pH-sensitive nanocarrier and delivery of the antitumor drugs. Materials and Methods: CDs were prepared by one-step hydrothermal treatment of citric acid and ethylenediamine. The nanoparticles were simply prepared by using microemulsion technology to form calcium phosphate (CaP) core and further coated with cationic lipids. Results: The structure was characterized by FTIR, XRD and TEM. In vitro release study revealed that DOX-CDs@LCP was pH dependent. The cytotoxicity assay demonstrated that it exhibited enhanced efficiency compared to the control group (DOX-CDs), but weaker than free DOX. The cellular uptake revealed that these pH-sensitive nanoparticles could be taken up effectively and deliver DOX into the cytoplasm to reach antitumor effect. The fluorescence imaging indicated that DOX-CDs@LCP mostly distributed in the tumor region due to the enhanced permeability and retention effect (EPR) to reduce its systematical toxicity. Importantly, an antitumor activity study demonstrated that the DOX-CDs@LCP nanoparticles had higher antitumor activity than any other groups and lower toxicity. The results showed that LCP could significantly promote the release in tumor microenvironment due to pH-response. The DOX-CDs could enhance load capacity and reduce drug premature releasing; real-time tracking of efficacy as confocal imaging contrast agent. Thus, DOX-CDs@LCP had antitumor capacity and lower systematic toxicity in tumor therapy. Conclusion: DOX-CDs@LCP were proven as a promising tumor pH-sensitive and imaging-guided drug delivery system for liver cancer chemotherapy.


Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Fosfatos de Cálcio/química , Doxorrubicina/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/química , Animais , Antibióticos Antineoplásicos/farmacocinética , Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Carbono/química , Doxorrubicina/farmacocinética , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Células Hep G2 , Humanos , Concentração de Íons de Hidrogênio , Lipídeos/química , Masculino , Camundongos , Neoplasias Experimentais/diagnóstico por imagem , Distribuição Tecidual , Microambiente Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Sci Rep ; 10(1): 2062, 2020 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-32029875

RESUMO

Reconstruction of bone defects represents a serious issue for orthopaedic and maxillofacial surgeons, especially in extensive bone loss. Adipose-derived mesenchymal stem cells (ADSCs) with tri-calcium phosphates (TCP) are widely used for bone regeneration facilitating the formation of bone extracellular matrix to promote reparative osteogenesis. The present study assessed the potential of cell-scaffold constructs for the regeneration of extensive mandibular bone defects in a minipig model. Sixteen skeletally mature miniature pigs were divided into two groups: Control group and scaffolds seeded with osteogenic differentiated pADSCs (n = 8/group). TCP-PLGA scaffolds with or without cells were integrated in the mandibular critical size defects and fixed by titanium osteosynthesis plates. After 12 weeks, ADSCs seeded scaffolds (n = 7) demonstrated significantly higher bone volume (34.8% ± 4.80%) than scaffolds implanted without cells (n = 6, 22.4% ± 9.85%) in the micro-CT (p < 0.05). Moreover, an increased amount of osteocalcin deposition was found in the test group in comparison to the control group (27.98 ± 2.81% vs 17.10 ± 3.57%, p < 0.001). In conclusion, ADSCs seeding on ceramic/polymer scaffolds improves bone regeneration in large mandibular defects. However, further improvement with regard to the osteogenic capacity is necessary to transfer this concept into clinical use.


Assuntos
Regeneração Óssea , Traumatismos Mandibulares/terapia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/fisiologia , Tecidos Suporte/química , Animais , Fosfatos de Cálcio/química , Diferenciação Celular/fisiologia , Modelos Animais de Doenças , Humanos , Osteogênese/fisiologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Suínos , Porco Miniatura
19.
BMC Biotechnol ; 20(1): 8, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005149

RESUMO

BACKGROUND: The translation from animal research into the clinical environment remains problematic, as animal systems do not adequately replicate the human in vivo environment. Bioreactors have emerged as a good alternative that can reproduce part of the human in vivo processes at an in vitro level. However, in vitro bone formation platforms primarily utilize stem cells only, with tissue based in vitro systems remaining poorly investigated. As such, the present pilot study explored the tissue behavior and cell survival capability within a new in vitro skeletal muscle tissue-based biomaterial organoid bioreactor system to maximize future bone tissue engineering prospects. RESULTS: Three dimensional printed ß-tricalcium phosphate/hydroxyapatite devices were either wrapped in a sheet of rat muscle tissue or first implanted in a heterotopic muscle pouch that was then excised and cultured in vitro for up to 30 days. Devices wrapped in muscle tissue showed cell death by day 15. Contrarily, devices in muscle pouches showed angiogenic and limited osteogenic gene expression tendencies with consistent TGF-ß1, COL4A1, VEGF-A, RUNX-2, and BMP-2 up-regulation, respectively. Histologically, muscle tissue degradation and fibrin release was seen being absorbed by devices acting possibly as a support for new tissue formation in the bioceramic scaffold that supports progenitor stem cell osteogenic differentiation. CONCLUSIONS: These results therefore demonstrate that the skeletal muscle pouch-based biomaterial culturing system can support tissue survival over a prolonged culture period and represents a novel organoid tissue model that with further adjustments could generate bone tissue for direct clinical transplantations.


Assuntos
Materiais Biocompatíveis/farmacologia , Músculo Esquelético/citologia , Organoides/citologia , Osteogênese , Células-Tronco/citologia , Engenharia Tecidual/métodos , Animais , Materiais Biocompatíveis/química , Biomarcadores/metabolismo , Reatores Biológicos , Fosfatos de Cálcio/química , Fosfatos de Cálcio/farmacologia , Diferenciação Celular/efeitos dos fármacos , Durapatita/química , Durapatita/farmacologia , Músculo Esquelético/metabolismo , Projetos Piloto , Impressão Tridimensional , Estudo de Prova de Conceito , Ratos , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Tecidos Suporte , Sobrevivência de Tecidos
20.
J Nanobiotechnology ; 18(1): 26, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005170

RESUMO

BACKGROUND: Gene therapy remains a significant challenge due to lots of barriers limiting the genetic manipulation technologies. As for non-viral delivery vectors, they often suffer insufficient performance due to inadequate cellular uptake and gene degradation in endosome or lysosome. The importance of overcoming these conserved intracellular barriers is increasing as the delivery of genetic cargo. RESULTS: A surface-functionalized non-viral vector involving the biomimetic mannitol moiety is initiated, which can control the cellular uptake and promote the caveolae-mediated pathway and intracellular trafficking, thus avoiding acidic and enzymatic lysosomal degradation of loaded gene internalized by clathrin-mediated pathway. Different degrees of mannitol moiety are anchored onto the surface of the nanoparticles to form bio-inspired non-viral vectors and CaP-MA-40 exhibits remarkably high stability, negligible toxicity, and significantly enhanced transgene expression both in vitro and in vivo. CONCLUSIONS: This strategy highlights a paradigmatic approach to construct vectors that need precise intracellular delivery for innovative applications.


Assuntos
Fosfatos de Cálcio/química , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Nanopartículas/química , Transgenes , Cavéolas/metabolismo , Linhagem Celular , Permeabilidade da Membrana Celular , Clatrina/metabolismo , Endossomos/metabolismo , Regulação Viral da Expressão Gênica , Técnicas de Transferência de Genes , Terapia Genética , Humanos , Lisossomos/metabolismo , Manitol/metabolismo , Transdução de Sinais , Propriedades de Superfície , Transdução Genética , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA