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The synthesis of ethoxido-bridged dinuclear oxidovanadium(IV) complexes of the general formula (HNEt3)[(VOL1-3)2(µ-OEt)] (1-3) with the azo dyes 2-(2'-carboxy-5'-X-phenylazo)-4-methylphenol (H2L1, X = H; H2L2, X = NO2) and 2-(2'-carboxy-5'-Br-phenylazo)-2-naphthol (H2L3) as ligands is reported. The ligands differ in the substituents at the phenyl ring to probe their influence on the redox behavior, biological activity, and magnetochemistry of the complexes, for which the results are presented and discussed. All synthesized ligands and vanadium(IV) complexes have been characterized by various physicochemical techniques, namely, elemental analysis, electrospray ionization mass spectrometry, spectroscopic methods (UV/vis and IR), and cyclic voltammetry. X-ray crystallography of 1 and 3 revealed the presence of a twisted arrangement of the edged-shared bridging core unit. In agreement with the distorted nature of the twisted core, antiferromagnetic exchange interactions were observed between the vanadium(IV) centers of the dinuclear complexes with a superexchange mechanism operative. These results have been verified by DFT calculations. The complexes were also screened for their in vitro cytotoxicity against HeLa and HT-29 cancer cell lines. The results indicated that all the synthesized vanadium(IV) complexes (1-3) were cytotoxic in nature and were specific to a particular cell type. Complex 1 was found to be the most potent against HeLa cells (IC50 value 1.92 µM).
Assuntos
Compostos Azo/química , Complexos de Coordenação/química , Magnetismo , Fenantridinas/química , Teoria Quântica , Vanádio/química , Ânions , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/toxicidade , Compostos Azo/farmacologia , Compostos Azo/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , Células HT29 , Células HeLa , Humanos , Concentração Inibidora 50 , Ligantes , Estrutura Molecular , Oxirredução , Fenantridinas/toxicidade , Vanádio/farmacologia , Vanádio/toxicidadeRESUMO
The current study describes the in-depth characterization of agar-gelatin based co-hydrogels, emulgels and bigels to have an insight about the differences in the properties of the formulations. Hydrogels have been extensively studied as vehicle for controlled drug release, whereas, the concept of emulgels and bigels is relatively new. The formulations were characterized by scanning electron microscopy, FTIR spectroscopy, XRD and mechanical properties. The biocompatibility and the ability of the formulations to be used as drug delivery vehicle were also studied. The scanning electron micrographs suggested the presence of internal phases within the agar-gelatin composite matrices of co-hydrogel, emulgel and bigel. FTIR and XRD studies suggested higher crystallinity of emulgels and bigels. Electrical impedance and mechanical stability of the emulgel and the bigel was higher than the hydrogel. The prepared formulations were found to be biocompatible and suitable for drug delivery applications.
Assuntos
Ágar/química , Preparações de Ação Retardada/síntese química , Gelatina/química , Hidrogéis/química , Metronidazol/química , Anti-Infecciosos/administração & dosagem , Anti-Infecciosos/química , Força Compressiva , Difusão , Módulo de Elasticidade , Dureza , Teste de Materiais , Metronidazol/administração & dosagem , Transição de FaseRESUMO
Staphylococcus aureus (S. aureus), a commensal organism found on the human skin, is commonly associated with nosocomial infections and exhibits virulence mediated by toxins and resistance to antibiotics. The global threat of antibiotic resistance has necessitated antimicrobial stewardship to improve the safe and appropriate use of antimicrobials; hence, there is an urgent demand for the advanced, cost-effective, and rapid detection of specific bacteria. In this regard, we aimed to selectively detect S. aureus using surface molecularly imprinted magnetic nanoparticles templated with a well-known biomarker protein A, specific to S. aureus. Herein, a highly selective surface molecularly imprinted polymeric thin layer was created on â¼250 nm magnetic nanoparticles (MNPs) through the immobilization of protein A to aldehyde functionalized MNPs, followed by monomer polymerization and template washing. This study employs the rational selection of monomers based on their computationally predicted binding affinity to protein A at multiple surface residues. The resulting MIPs from rationally selected monomer combinations demonstrated an imprinting factor as high as â¼5. Selectivity studies revealed MIPs with four-fold higher binding capacity (BC) to protein A than other non-target proteins, such as lysozyme and serum albumin. In addition, it showed significant binding to S. aureus, whereas negligible binding to other non-specific Gram-negative, i.e. Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), and Gram-positive, i.e. Bacillus subtilis (B. subtilis), bacteria. This MIP was employed for the capture and specific detection of fluorescently labeled S. aureus. Quantitative detection was performed using a conventional plate counting technique in a linear detection range of 101-107 bacterial cells. Remarkably, the MIPs also exhibited approximately 100% cell recovery from milk samples spiked with S. aureus (106 CFU mL-1), underscoring its potential as a robust tool for sensitive and accurate bacterial detection in dairy products. The developed MIP exhibiting high affinity and selective binding to protein A finds its potential applications in the magnetic capture and selective detection of protein A as well as S. aureus infections and contaminations.
Assuntos
Nanopartículas de Magnetita , Impressão Molecular , Proteína Estafilocócica A , Staphylococcus aureus , Propriedades de Superfície , Staphylococcus aureus/isolamento & purificação , Nanopartículas de Magnetita/química , Proteína Estafilocócica A/química , Proteína Estafilocócica A/metabolismo , Tamanho da Partícula , Polímeros Molecularmente Impressos/química , HumanosRESUMO
There is a dearth of adhesive systems capable of forming stable bonds between restorative materials and tooth surfaces. To address the concern, this study determined the effects of using methacrylate-functionalized boron nitride nanosheets (BNNSs) in a polymeric dental adhesive system. The bisphenol A glycidyl dimethacrylate (BisGMA):2 hydroxyethyl methacrylate (HEMA) (60:40) adhesive monomer blend with a photoinitiator was filled with 0 wt% (control), 0.1 wt%, and 1 wt% BNNSs and light cured. Fourier transform infrared spectroscopy was performed to determine the conversion degree of monomer double bonds (DoC). Water absorption and solubility were measured. Flexural strength and Youngs's modulus were evaluated to determine the mechanical properties of the composite adhesive system. Finally, dentin bond strength degradation and fracture mode were quantified with a microtensile bond test to confirm the bonding ability of the developed adhesive system. Results showed that the incorporation of BNNSs increased DoC (9.8% and 5.4% for 0.1 and 1 wt%, respectively), but it did not affect water sorption (101.9-119.72 (µg/mm3)), solubility (2.62-5.54 (µg/mm3)), Young's modulus (529.1-1716.1 MPa), or microtensile bond strength (46.66-54.72 MPa). Further studies are needed with varying BNNS loading percentages from 0.1 wt% to 1 wt% in order to more comprehensively determine the effect of BNNSs on dental adhesives.
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BACKGROUND: Zirconia is a widely used material in the dental industry due to its excellent mechanical and aesthetic properties. Recently, a new 3D printing process called suspension-enclosing projection stereolithography (SEPS) was introduced to fabricate zirconia dental restorations. However, the effect of the sintering time and temperature on the properties of zirconia produced via SEPS has not been fully investigated. METHODS: Zirconia slurries were prepared with varying percentages of zirconia powders and 3D printing resins, and 5Y-TZP (5 mol% yttria-stabilized zirconia) (n = 40) and 3Y-TZP (3 mol% yttria-stabilized zirconia) (n = 40) bar specimens were fabricated via SEPS manufacturing. The specimens were sintered at different temperatures and dwell times, and their flexural strength, density, and phase composition were measured. The viscosity of the slurries was also measured. Statistical analysis was performed using Welch's ANOVA and Kruskal-Wallis tests to evaluate the impact of the sintering conditions. RESULTS: Significant differences in flexural strength (p < 0.01) were observed between the 5Y-TZP samples, with those sintered at 1530 °C for 120 min showing an average strength of 268.34 ± 44.66 MPa, compared to 174.16 ± 42.29 MPa for those sintered at 1450 °C for 120 min. In terms of density, significant differences (p < 0.01) were noted for the 3Y-TZP specimens, with an average density of 6.66 ± 0.49 g/cm3 for samples sintered at 1530 °C for 120 min, versus 5.75 ± 0.55 g/cm3 for those sintered at 1530 °C for 10 min. X-ray diffraction confirmed the presence of a predominantly tetragonal phase in both materials. CONCLUSIONS: Zirconia printed via SEPS manufacturing can be sintered at a higher temperature with shorter dwell times, thereby producing high density samples. Different sintering conditions can be used to fully sinter 3D-printed zirconia for potential dental applications.
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The emergence of antibiotic resistance has led to a global crisis for the physician to handle infection control issues. All antibiotics, including colistin, have lost efficiency against emerging drug-resistant bacterial strains due to the production of metallo-ß-lactamases (MBLs) and serine-ß-lactamases (SBLs). Therefore, it is of the utmost importance to design inhibitors against these enzymes to block the hydrolytic action against antibiotics being used. Although various novel ß-lactamase inhibitors are being authorized or are under clinical studies, the coverage of their activity spectrum does not include MDR organisms expressing multiple classes of ß-lactamases at a single time. This study reports three novel broad-spectrum inhibitors effective against both SBLs and MBLs. Virtual screening, molecular docking, molecular dynamics simulations, and an in silico pharmacokinetic study were performed to identify the lead molecules with broad-spectrum ability to inhibit the hydrolysis of ß-lactam. The selected compounds were further assessed by in vitro cell assays (MIC, 50% inhibitory concentration [IC50], kinetics, and fluorescence against class A, B, and C type ß-lactamases) to confirm their efficacies. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to check the toxicity of screened lead molecules. All three selected inhibitors were found to reduce MIC and showed good affinity against all the SBLs and MBLs produced by class A, B, and C type ß-lactamases. These nontoxic novel non-ß-lactam broad-spectrum inhibitors bind to the active site residues of selected ß-lactamases, which are crucial for ß-lactam antibiotic hydrolysis. These inhibitors may be proposed as a future drug candidate in combination with antibiotics as a single formulation to control infection caused by resistant strains. Hence, this study plays a significant role in the cure of infections caused by antibiotic-resistant bacteria. IMPORTANCE Several inhibitors for usage in conjunction with antibiotics have been developed. However, to date, there is no commercially available broad-spectrum ß-lactamase inhibitor that targets both MBLs and SBLs. Here, we showed three novel broad-spectrum inhibitors with promising results through computational techniques and in vitro studies. These inhibitors are effective against both SBLs and MBLs and hence could be used as future drug candidates to treat infections caused by multidrug-resistant bacteria producing both types of enzymes (SBLs and MBLs).
Assuntos
Inibidores de beta-Lactamases , beta-Lactamases , Inibidores de beta-Lactamases/farmacologia , Inibidores de beta-Lactamases/química , Antibacterianos/farmacologia , Hidrólise , Colistina/farmacologia , Simulação de Acoplamento Molecular , beta-Lactamas/farmacologia , Bactérias/metabolismo , Serina/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
Diabetic foot infection caused by multidrug-resistant bacteria, is becoming serious problem. Moreover, polymicrobial biofilms contribute significantly to the persistent infections. In the present study, we investigated the effectiveness of novel toluidine blue conjugated chitosan coated gold-silver core-shell nanoparticles (TBO-chit-Au-AgNPs) mediated photodynamic therapy and demonstrate their use as a nontoxic antibacterial therapy to combat diabetic foot ulcer (DFU) caused by multi-drug resistant strains both in monomicrobial and polymicrobial state of infection. In vitro efficacy of TBO-chit-Au-AgNPs mediated photodynamic therapy (PDT) against polymicrobial biofilms was determined using standard plate count method and compared with that of monomicrobial biofilms of each species. Different anti-biofilm assays and microscopic studies were performed to check the efficacy of TBO-chit-Au-AgNPs mediated PDT, displayed significant decrease in the formation of biofilm. Finally, its therapeutic potential was validated in vivo type-2DFU. Cytokines level was found reduced, using nano-phototheranostic approach, indicating infection control. Expression profile of growth factors confirmed both the pathogenesis and healing of DFU. Hence, we conclude that TBO-chit-Au-AgNPs mediated PDT is a promising anti-bacterial therapeutic approach which leads to a synergistic healing of DFU caused by MDR bacterial strains.
Assuntos
Antibacterianos/uso terapêutico , Pé Diabético/tratamento farmacológico , Ouro/uso terapêutico , Nanopartículas Metálicas/uso terapêutico , Prata/uso terapêutico , Cloreto de Tolônio/uso terapêutico , Animais , Biofilmes/efeitos dos fármacos , Pé Diabético/microbiologia , Masculino , Fotoquimioterapia , Ratos WistarRESUMO
Angiogenic-osteogenic cell encapsulation system is a technical need for human mesenchymal stem cell (hMSC)-based bone tissue engineering (BTE). Here, we have developed a highly efficient hMSC encapsulation system by incorporating bivalent cobalt doped nano-hydroxyapatite (HAN) and gum tragacanth (GT) as angiogenic-osteogenic components into the calcium alginate (CA) beads. Physico-chemical characterizations revealed that the swelling and degradation of HAN incorporated CA-GT beads (GT-HAN) were 1.34 folds and 2 folds higher than calcium alginate (CA) beads. Furthermore, the diffusion coefficient of solute molecule was found 2.5-fold higher in GT-HAN with respect to CA bead. It is observed that GT-HAN supports the long-term viability of encapsulated hMSC and causes 50% less production of reactive oxygen species (ROS) in comparison to CA beads. The expression of osteogenic differentiation markers was found 1.5-2.5 folds higher in the case of GT-HAN in comparison to CA. A similar trend was observed for hypoxia inducible factor 1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF). The soluble secretome from hMSC encapsulated in the GT-HAN induced proliferation of endothelial cells and supported tube formation (2.5-fold higher than CA beads). These results corroborated that GT-HAN could be used as an angiogenic-osteogenic cell encapsulation matrix for hMSC encapsulation and BTE application.
Assuntos
Alginatos/química , Osso e Ossos/metabolismo , Células Imobilizadas/metabolismo , Cobalto/química , Durapatita/química , Células-Tronco Mesenquimais/metabolismo , Neovascularização Fisiológica , Osteogênese , Engenharia Tecidual , Tragacanto/química , HumanosRESUMO
Evaluation of the biological properties of silanized graphene oxide is important in the context of biomedical applications of the material. In this study, we have evaluated the toxicity, immunogenicity and other biological properties like osteogenicity of silanized graphene oxide (SiGO). Graphene oxide (GO) was silanized using a common silanizing agent namely (3-aminopropyl) triethoxysilane (APTES). Silanization was confirmed through infrared spectroscopy and elemental mapping. Post-silanization, we did not observe any significant changes in the morphology of GO. Silanization leads to an increase in the interlayer distance and disorder in the lattice. Study of in vitro toxicity of SiGO on three different cell lines namely primary human dermal fibroblast, murine embryonic fibroblast and human osteosarcoma cell lines revealed that toxicity of SiGO was significantly less than GO. We further showed that in vitro immune activation of macrophage was less in the case of SiGO in comparison to GO. Profiling of osteogenic differentiation of human mesenchymal stem cell revealed that SiGO is less osteogenic than GO. Study of acute toxicity in the murine model indicated that GO was hepatotoxic at experimental concentration whereas SiGO did not show any significant toxicity. This study implied that SiGO is a better biocompatible material than GO.
Assuntos
Materiais Biocompatíveis/farmacologia , Grafite/farmacologia , Silanos/farmacologia , Adulto , Fosfatase Alcalina/metabolismo , Animais , Contagem de Células Sanguíneas , Peso Corporal/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Derme/citologia , Fibroblastos/efeitos dos fármacos , Grafite/toxicidade , Hemoglobinas/metabolismo , Humanos , Camundongos , Células NIH 3T3 , Tamanho do Órgão/efeitos dos fármacos , Osteocalcina/metabolismo , Osteogênese/efeitos dos fármacos , Silanos/toxicidade , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Testes de Toxicidade , Difração de Raios XRESUMO
The efficacy and toxicity of drugs depend not only on their potency but also on their ability to reach the target sites in preference to non-target sites. In this regards destabilization of delivery vehicles induced by light can be an effective strategy for enhancing drug delivery with spatial and temporal control. Herein we demonstrate that the photoinduced isomerization from closed (hydrophobic) to open isomeric form (hydrophilic) of a novel DHI encapsulated in liposome leads to potential light-controlled drug delivery vehicles. We have used steady state and picosecond resolved dynamics of a drug 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS) incorporated in liposome to monitor the efficacy of destabilization of liposome in absence and presence UVA irradiation. Steady state and picosecond resolved polarization gated spectroscopy including the well-known strategy of solvation dynamics and Förster resonance energy transfer; reveal the possible mechanism out of various phenomena involved in destabilization of liposome. We have also investigated the therapeutic efficacy of doxorubicin (DOX) delivery from liposome to cervical cancer cell line HeLa. The FACS, confocal fluorescence microscopic and MTT assay studies reveal an enhanced cellular uptake of DOX leading to significant reduction in cell viability (â¼40%) of HeLa followed by photoresponsive destabilization of liposome. Our studies successfully demonstrate that these DHI encapsulated liposomes have potential application as a smart photosensitive drug delivery system.
Assuntos
Antineoplásicos/farmacologia , Doxorrubicina/farmacologia , Composição de Medicamentos/métodos , Indolizinas/metabolismo , Lipossomos/efeitos da radiação , Naftalenossulfonato de Anilina/química , Antineoplásicos/metabolismo , Linhagem Celular Transformada , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Doxorrubicina/metabolismo , Liberação Controlada de Fármacos , Feminino , Corantes Fluorescentes/química , Células HeLa , Humanos , Interações Hidrofóbicas e Hidrofílicas , Indolizinas/química , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Cinética , Lipossomos/química , Lipossomos/metabolismo , Processos Fotoquímicos , Raios UltravioletaRESUMO
Considering the fact that life on Earth is carbon based, carbon materials are being introduced in biological systems. However, very limited information exists concerning the potential effects of different structures of carbon materials on biological systems. In the present study, poly(lactic-co-glycolic acid) (PLGA)-based carbonaceous composites were developed by reinforcing 1 wt% of three different carbon-based materials i.e. carbon nanotubes (CNTs-1D), graphene nanoplatelets (GNPs-2D), and activated carbon (AC-3D). The developed composites were characterized for physicochemical, biological, and mechanical properties. Along with their hemocompatible nature, the composites exhibited better swelling ratio, degradation percentage, bioactivity, and tensile strength. The improvement in hydrophilicity and protein adsorption resulted in the enhancement of cell proliferation and differentiation. Overall, sheet-like GNPs showed the strongest effect on the composite's properties due to their larger exposed area. These results demonstrate the potential of PLGA-based carbonaceous composites for accelerating bone tissue regeneration.
Assuntos
Materiais Biocompatíveis/química , Regeneração Óssea/fisiologia , Carbono/química , Ácido Láctico/química , Ácido Poliglicólico/química , Fosfatase Alcalina/metabolismo , Animais , Calcificação Fisiológica , Linhagem Celular , Sobrevivência Celular , Grafite/química , Humanos , Técnicas In Vitro , Teste de Materiais , Nanoestruturas/química , Nanotubos de Carbono/química , Osteoblastos/citologia , Osteoblastos/fisiologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Ligação Proteica , Resistência à Tração , Engenharia Tecidual/métodos , Alicerces Teciduais/químicaRESUMO
In the global context of increasing colonic diseases, colon specific oral drug delivery systems have shown promise as an effective therapeutic modality. Herein, we developed a mesoporous silica nanoparticle (MSN) based enzyme responsive materials for colon specific drug delivery. We have utilized guar gum, a natural carbohydrate polymer as a capping layer to contain a model drug, such as 5-flurouracil (5FU) within the mesoporous channels of MSN. Analytical characterization including electron microscopy, PXRD, nitrogen sorption, thermogravimetric analysis and FTIR, confirmed that the synthesized MSN with size less than 100nm is of MCM-41type. The studies further showed that the MSN maintained their discrete nanoparticle identity after guar gum capping through non-covalent interaction. The release of 5FU from guar gum capped MSN (GG-MSN) was specifically triggered via enzymatic biodegradation of guar gum by colonic enzymes in the simulated colonic microenvironment. Subsequently, the released drug manifested anticancer activity in colon cancer cell lines in vitro confirmed by flow cytometry and biochemical assay. The drug loaded GG-MSN system also demonstrated near perfect 'zero release' property in absence of enzymes in different simulated conditions of the gastrointestinal tract. Our study provides an important intermediate step to apply such GG-MSN based engineered nanomaterials for further detailed in vivo investigation.
Assuntos
Colo/metabolismo , Sistemas de Liberação de Medicamentos , Galactanos/química , Mananas/química , Nanopartículas Metálicas/química , Gomas Vegetais/química , Dióxido de Silício/química , Administração Oral , Adsorção , Antineoplásicos/administração & dosagem , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Citometria de Fluxo , Fluoruracila/administração & dosagem , Trato Gastrointestinal/efeitos dos fármacos , Humanos , Microscopia Eletrônica , Nitrogênio/química , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Difração de Raios XRESUMO
In this article, we validated the use of electric current as an external stimulus to induce an enhancement of drug release from magnetic nanoparticle (MNP) incorporated organogels (magnetogel) under iontophoretic conditions. For this purpose, we adopted a simple, two-step synthesis route to incorporate magnetic (Fe3O4) nanoparticles (MNP) and ciprofloxacin hydrochloride within the network of a soybean oil-based oleogel using stearic acid as gelator. We fabricated a series of MNP incorporated oleogels by varying the wt% of MNPs while keeping a constant weight ratio of soybean oil:stearic acid. The microstructures of the magnetogels were analyzed in MNP concentration-dependent manner by optical microscopy, powder X-ray diffraction, FTIR, mechanical, and electrical studies. Detailed analysis of the electrical properties revealed that the gel sample with a maximum proportion of MNP (S4) allowed the maximum passage of current through it among all the compositions. Under the iontophoretic environment of the active condition, we observed nearly 2.5 fold increase in cumulative drug release in case of sample S4 compared to the corresponding passive condition. These observations suggested that in future, our magnetogel formulation can be further developed as AC field induced 'remote controlled' agent for therapeutic application.
Assuntos
Nanopartículas de Magnetita/química , Sistemas de Liberação de Medicamentos/métodos , Compostos Orgânicos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios XRESUMO
There is a dearth of biologically active matrices for the encapsulation of bone cells. Here, we hypothesize that the use of gum tragacanth (GT) with alginate might improve the biological properties of calcium alginate (CA) beads, a common cell encapsulation system. We show that the incorporation of GT in the bead-composition significantly improves the molecular transport, swelling and degradation properties of the CA bead. Although no significant molecular interaction between GT and CA was found, a decrease in the concentration of calcium with an increase in GT concentration was noticed. We show that the presence of GT in the bead-composition resulted in improved viability, proliferation, and differentiation of encapsulated bone cells. We further demonstrate that bone cell loaded CA-GT beads are capable of inducing angiogenesis. In conclusion, we prove that CA-GT beads are more osteo-conductive and proangiogenic in comparison to pure CA beads.
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The present study delineates the preparation, characterization and application of gelatin-carboxymethyl chitosan scaffolds for dermal tissue engineering. The effect of carboxymethyl chitosan and gelatin ratio was evaluated for variations in their physico-chemical-biological characteristics and drug release kinetics. The scaffolds were prepared by freeze drying method and characterized by SEM and FTIR. The study revealed that the scaffolds were highly porous with pore size ranging between 90 and 170µm, had high water uptake (400-1100%) and water retention capacity (>300%). The collagenase mediated degradation of the scaffolds was dependent on the amount of gelatin present in the formulation. A slight yet significant variation in their biological characteristics was also observed. All the formulations supported adhesion, spreading, growth and proliferation of 3T3 mouse fibroblasts. The cells seeded on the scaffolds also demonstrated expression of collagen type I, HIF1α and VEGF, providing a clue regarding their growth and proliferation along with potential to support angiogenesis during wound healing. In addition, the scaffolds showed sustained ampicillin and bovine serum albumin release, confirming their suitability as a therapeutic delivery vehicle during wound healing. All together, the results suggest that gelatin-carboxymethyl chitosan based scaffolds could be a suitable matrix for dermal tissue engineering applications.
Assuntos
Materiais Biocompatíveis/química , Quitosana/análogos & derivados , Gelatina/química , Alicerces Teciduais/química , Células 3T3 , Ampicilina/química , Animais , Quitosana/química , Liberação Controlada de Fármacos , Camundongos , Porosidade , Soroalbumina Bovina/química , Pele/fisiopatologia , Engenharia Tecidual , CicatrizaçãoRESUMO
The present study delineates the synthesis and characterization of cobalt doped proangiogenic-osteogenic hydroxyapatite. Hydroxyapatite samples, doped with varying concentrations of bivalent cobalt (Co(2+)) were prepared by the ammoniacal precipitation method and the extent of doping was measured by ICP-OES. The crystalline structure of the doped hydroxyapatite samples was confirmed by XRD and FTIR studies. Analysis pertaining to the effect of doped hydroxyapatite on cell cycle progression and proliferation of MG-63 cells revealed that the doping of cobalt supported the cell viability and proliferation up to a threshold limit. Furthermore, such level of doping also induced differentiation of the bone cells, which was evident from the higher expression of differentiation markers (Runx2 and Osterix) and better nodule formation (SEM study). Western blot analysis in conjugation with ELISA study confirmed that the doped HAp samples significantly increased the expression of HIF-1α and VEGF in MG-63 cells. The analysis described here confirms the proangiogenic-osteogenic properties of the cobalt doped hydroxyapatite and indicates its potential application in bone tissue engineering.
Assuntos
Materiais Biocompatíveis/química , Cobalto/química , Durapatita/química , Osteogênese/efeitos dos fármacos , Engenharia Tecidual/métodos , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/toxicidade , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Durapatita/farmacologia , Hemólise/efeitos dos fármacos , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Success of bone tissue engineering (BTE) relies on the osteogenic microarchitecture of the biopolymeric scaffold and appropriate spatiotemporal distribution of therapeutic molecules (growth factors and drugs) inside it. However, the existing technologies have failed to address both the issues together. Keeping this perspective in mind, we have developed a novel three-dimensional (3D) implant prototype by stacking hexagonal close packed (HCP) layers of calcium alginate beads. The HCP arrangement of the beads lead to a patterned array of interconnected tetrahedral and octahedral pores of average diameter of 142.9 and 262.9 µm, respectively, inside the implant. The swelling pattern of the implants changed from isotropic to anisotropic in the z-direction in the absence of bivalent calcium ions (Ca2+) in the swelling buffer. Incubation of the implant in simulated body fluid (SBF) resulted in a 2.7-fold increase in the compressive modulus. The variation in the relaxation times as derived from the Weichert viscoelasticity model predicted a gradual increase in the interactions among the alginate molecules in the matrix. We demonstrated the tunability of the spatiotemporal drug release from the implant in a tissue mimicking porous semisolid matrix as well as in conventional drug release set up by changing the spatial coordinates of the "drug loaded depot layer" inside the implant. The therapeutic potential of the implant was confirmed against Escherichia coli using metronidazole as the model drug. Detailed analysis of cell viability, cell cycle progression, and cytoskeletal reorganization using osteoblast cells (MG-63) proved the osteoconductive nature of the implant. Expression of differentiation markers such as alkaline phosphatase, runx2, and collagen type 1 in human mesenchymal stem cell in vitro confirmed the osteogenic nature of the implant. When tested in vivo, VEGF loaded implant was found capable of inducing angiogenesis in a mice model. In conclusion, the bead based implant may find its utility in non-load-bearing BTE.
Assuntos
Alginatos/química , Animais , Diferenciação Celular , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Humanos , Células-Tronco Mesenquimais , Camundongos , Osteogênese , Engenharia Tecidual , Alicerces TeciduaisRESUMO
Over the past decade, researchers have been trying to develop alternative gel based formulations in comparison to the traditional hydrogels and emulgels. In this perspective, bigels were synthesized by mixing gelatin hydrogel and stearic acid based organogel by hot emulsification method. Two types of bigels were synthesized using sesame oil and soy bean oil based stearate organogels. Gelatin based emulgels prepared using sesame oil and soy bean oil were used as the controls. Microscopic studies revealed that the bigels contained aggregates of droplets, whereas, emulgels showed dispersed droplets within the continuum phase. The emulgels showed higher amount of leaching of oils, whereas, the leaching of the internal phase was negligible from the bigels. Presence of organogel matrix within the bigels was confirmed by XRD, FTIR and DSC methods. Bigels showed higher mucoadhesive and mechanical properties compared to emulgels. Cyclic creep-recovery and stress relaxation studies confirmed the viscoelastic nature of the formulations. Four elemental Burger's model was employed to analyze the cyclic creep-recovery data. Cyclic creep-recovery studies suggested that the deformation of the bigels were lower due to the presence of the organogels within its structure. The formulations showed almost 100% recovery after the creep stage and can be explained by the higher elastic nature of the formulations. Stress relaxation study showed that the relaxation time was higher in the emulgels as compared to the bigels. Also, the % relaxation was higher in emulgels suggesting its fluid dominant nature. The in vitro biocompatibility of the bigels was checked using human epidermal keratinocyte cell line (HaCaT). Both emulgels and bigels were biocompatible in nature. The in vitro drug (ciprofloxacin) release behavior indicated non-Fickian diffusion of the drug from the matrices. The drug release showed good antimicrobial effect against Escherichia coli. Based on the results, it was concluded that the developed bigels may have huge potential to be used as alternatives to emulgels.