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1.
J Nanosci Nanotechnol ; 20(2): 680-691, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383063

RESUMO

BN has important roles in several physiological events, including bone growth and immune system. New infection-free cranioplasty and has an osteogenic activities material that are compatible with tissue are being developed. We aimed in our study to examine whether different combinations of Boron-nitride/Hydroxyapatite are embedded into the scaffold in the treatment of calvarial defects. 200 adult female Sprague-Dawley rats divided into 10 equal groups. Osteotomy was made by trepan drill in 8 mm diameter. The scaffolds were placed in the rats and were left to recovery for 2 months. During the experiment, CT scans were taken from the calvarial areas of the rats in the 2nd, 4th and 8th weeks. Significant healing was observed in defect diameters in 2.5% BN+10% HA, 2.5% BN and 5% BN+10% HA, respectively. After 8 weeks, it was seen that the amounts of OPN, BMP-2, RunX2 and ALP mRNA expression significantly decreased in 2.5% BN+10% HA, 2.5% BN, 5% BN+10% HA and 5% BN groups. It was shown that bone recovery was at the best grade in the groups, which contained 2.5% BN and 2.5% BN+10% HA when compared to the other groups. BN is a very promising agent that will be used in reconstructive surgery for the treatment of calvarial bone defects.

2.
J Vis Exp ; (136)2018 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-29985330

RESUMO

A synergistic drug combination has a higher efficacy compared to the effects of individual drugs. Checkerboard assays, where drugs are combined in many doses, allow sensitive measurement of drug interactions. However, these assays are costly and do not scale well for measuring interaction among many drugs. Several recent studies have reported drug interaction measurements using a diagonal sampling of the traditional checkerboard assay. This alternative methodology greatly decreases the cost of drug interaction experiments and allows interaction measurement for combinations with many drugs. Here, we describe a protocol to measure the three pairwise interactions and one three-way interaction among three antibiotics in duplicate, in five days, using only three 96-well microplates and standard laboratory equipment. We present representative results showing that the three-antibiotic combination of Levofloxacin + Nalidixic Acid + Penicillin G is synergistic. Our protocol scales up to measure interactions among many drugs and in other biological contexts, allowing for efficient screens for multi-drug synergies against pathogens and tumors.


Assuntos
Sinergismo Farmacológico , Quimioterapia Combinada/métodos , Humanos , Projetos de Pesquisa
3.
Microsc Microanal ; 23(5): 891-899, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28835297

RESUMO

Calcium phosphate derivatives have been widely employed in medical and dental applications for hard tissue repair, as they are the main inorganic constitution of hard tissue; such as bones and teeth. Owing to their excellent osteoconductive and bioactive properties, hydroxyapatite- (HA) based ceramics are the best candidates of this group for medical, bioscience, and dental applications. However, when replacing a bone or tooth, HA is not able to sustain similar mechanical properties. In this study, to improve the mechanical properties, nanoscale hexagonal boron nitride with different compositional percentages was added to the nano HA to form composites. The effect of compositional changes and sintering parameters on microstructural and morphological properties of the ceramic composites was comparatively investigated. Detailed chemical characterization of the composite materials was carried out using X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy, whereas scanning electron microscopy and atomic force microscopy investigations were employed to monitor morphological and surface features. Additional transmission electron microscopy investigations were carried out to reveal the nanostructure and crystal structure of the composites.

4.
Colloids Surf B Biointerfaces ; 158: 175-181, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28689100

RESUMO

Small interfering RNAs (siRNA) are short nucleic acid fragments of about 20-27 nucleotides, which can inhibit the expression of specific genes. siRNA based RNAi technology has emerged as a promising method for the treatment of a variety of diseases. However, a major limitation in the therapeutic use of siRNA is its rapid degradation in plasma and cellular cytoplasm, resulting in short half-life. In addition, as siRNA molecules cannot penetrate into the cell efficiently, it is required to use a carrier system for its delivery. In this work, chemically and morphologically different calcium phosphate (CaP) nanoparticles, including spherical-like hydroxyapatite (HA-s), needle-like hydroxyapatite (HA-n) and calcium deficient hydroxyapatite (CDHA) nanoparticles were synthesized by the sol-gel technique and the effects of particle characteristics on the binding capacity of siRNA were investigated. In order to enhance the gene loading efficiency, the nanoparticles were functionalized with arginine and the morphological and their structural characteristics were analyzed. The addition of arginine did not significantly change the particle sizes; however, it provided a significantly increased binding of siRNA for all types of CaP nanoparticles, as revealed by spectrophotometric measurements analysis. Arginine functionalized HA-n nanoparticles showed the best binding behavior with siRNA among the other nanoparticles due to its high, positive zeta potential (+18.8mV) and high surface area of Ca++ rich "c" plane. MTT cytotoxicity assays demonstrated that all the nanoparticles tested herein were biocompatible. Our results suggest that high siRNA entrapment in each of the three modified non-toxic CaP nanoparticles make them promising candidates as a non-viral vector for delivering therapeutic siRNA molecules to treat cancer.


Assuntos
Aminoácidos/química , Fosfatos de Cálcio/química , Nanopartículas/química , RNA Interferente Pequeno/química , Técnicas de Transferência de Genes
5.
Mater Sci Eng C Mater Biol Appl ; 79: 343-353, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28629027

RESUMO

In this study, commercial pure titanium samples were coated with nano hydroxyapatite-nano hexagonal boron nitride (nano HA-nano hBN) composite by electrophoretic deposition (EPD). The effect of process parameters (applied voltage, deposition time and solid concentration) on the coating morphology, thickness and the adhesion behavior were studied systematically and crack free nano hBN-nano HA composite coating production was achieved for developing bioactive coatings on titanium substrates for orthopedic applications. For the examination of structural and morphological characteristics of the coating surfaces, various complementary analysis methods were performed. For the structural characterization, XRD and Raman Spectroscopy were used while, Scanning Electron Microscopy (SEM) equipped with an energy dispersive spectrometer (EDS) and Transmission Electron Microscopy (TEM) techniques were carried out for revealing the morphological characterization. The results showed that nano HA-nano hBN were successfully deposited on Ti surface with uniform, crack-free coating by EPD. The amounts of hBN in suspension are considered to have no effect on coating thickness. By adding hBN into HA, the morphology of HA did not change and hBN has no significant effect on porous structure. These nanostructured surfaces are expected to be suitable for proliferation of cells and have high potential for bioactive materials.


Assuntos
Compostos de Boro/química , Materiais Revestidos Biocompatíveis , Durapatita , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Titânio
6.
Mater Sci Eng C Mater Biol Appl ; 58: 1082-9, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26478407

RESUMO

Boron and its derivatives are effective in bone recovery and osteointegration. However, increasing the boron levels in body liquids may cause toxicity. The aim of our study is to investigate serum boron levels using ICP-MS after implantation of different ratios of nano-hBN-HA composites in rat femurs. All rats were (n=126) divided into five experimental groups (n=24) and one healthy group (6 rats); healthy (Group1), femoral defect + %100 HA (Group2), femoral defect + %2.5 hBN + %97.5 HA (Group3), femoral defect + %5 hBN + %95 HA (Group4), femoral defect + %10 hBN + %90 HA (Group5), femoral defect + %100 hBN (Group6). The femoral defect was created in the distal femur (3mm drill-bit). Each implant group was divided into four different groups (n=24) also 6 rats sacrificed for each groups in one week intervals during four weeks. In our results; at 1, 2, 3, and 4 weeks after implantation near bone tissue, serum levels of boron were evaluated using ICP-MS. We demonstrated that neither short-term nor long-term implantation of hBN-HA composite resulted in statistically increased serum boron levels in experimental groups compared to healthy group. In conclusion, this study investigated the implant material produced form hBN-HA for the first time. Our data suggest that hBN is a new promising target for biomaterial and implant bioengineers.


Assuntos
Apatitas/química , Compostos de Boro/química , Boro/sangue , Fêmur/cirurgia , Nanocompostos/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Boro/metabolismo , Compostos de Boro/farmacocinética , Ratos , Ratos Sprague-Dawley
7.
Microsc Microanal ; 21(6): 1379-1386, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26650068

RESUMO

Irradiation damage, caused by the use of beams in electron and ion microscopes, leads to undesired physical/chemical material property changes or uncontrollable modification of structures. Particularly, soft matter such as polymers or biological materials is highly susceptible and very much prone to react on electron/ion beam irradiation. Nevertheless, it is possible to turn degradation-dependent physical/chemical changes from negative to positive use when materials are intentionally exposed to beams. Especially, controllable surface modification allows tuning of surface properties for targeted purposes and thus provides the use of ultimate materials and their systems at the micro/nanoscale for creating functional surfaces. In this work, XeF2 and I2 gases were used in the focused ion beam scanning electron microscope instrument in combination with gallium ion etching of high-density polyethylene surfaces with different beam currents and accordingly different gas exposure times resulting at the same ion dose to optimize and develop new polymer surface properties and to create functional polymer surfaces. Alterations in the surface morphologies and surface chemistry due to gas-assisted etching-based nanostructuring with various processing parameters were tracked using high-resolution SEM imaging, complementary energy-dispersive spectroscopic analyses, and atomic force microscopic investigations.

8.
J Appl Toxicol ; 34(4): 373-9, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24474238

RESUMO

The present study was designed to investigate genotoxic and cytotoxic effects and oxidative damage of increasing concentrations of nano-hydroxyapatite (5, 10, 20, 50, 75, 100, 150, 300, 500 and 1000 ppm) in primary human blood cell cultures. Cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] assay and lactate dehydrogenase release, while total antioxidant capacity and total oxidative stress levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by sister chromatid exchange, micronuclei, chromosome aberration assays and 8-oxo-2-deoxyguanosine level as indicators of genotoxicity. The results of [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] and lactate dehydrogenase assays showed that the higher concentrations (150, 300, 500 and 1000 ppm) of hydroxyapatite nanoparticles (HAP NPs) decreased cell viability. HAP NPs led to increases of total oxidative stress (300, 500 and 1000 ppm) levels and decreased total antioxidant capacity (150, 300, 500 and 1000 ppm) levels in cultured human blood cells. On the basis of increasing concentrations, HAP NPs caused significant increases of sister chromatid exchange, micronuclei, chromosome aberration rates and 8-oxo-2-deoxyguanosine levels as compared to untreated culture. In conclusion, the obtained in vitro results showed that HAP NPs had dose-dependent effects on inducing oxidative damage, genotoxicity and cytotoxicity in human blood cells.


Assuntos
Dano ao DNA , Durapatita/toxicidade , Linfócitos/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Nanopartículas , Troca de Cromátide Irmã/efeitos dos fármacos , Antioxidantes/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Relação Dose-Resposta a Droga , Durapatita/química , Humanos , Linfócitos/metabolismo , Linfócitos/patologia , Masculino , Testes de Mutagenicidade , Estresse Oxidativo/efeitos dos fármacos , Cultura Primária de Células
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