filter by: Publication Year
(Descending) Articles
Diamond and Related Materials (09259635) 151
A novel platform was proposed for the development of glucose biosensors, focusing on an innovative fabrication process based on simple surface modification techniques and non-enzymatic catalytic materials. The platform aimed to enhance biomolecule detection by utilizing a disposable and portable electrode design. Specifically, a screen-printed carbon electrode (SPCE) was selected as the base, and its carbon substrate was engraved using a pulsed fiber laser. Consequently, multi-walled carbon nanotubes (MWCNT) and zinc oxide (ZnO) nanoparticles were deposited on the surface of the laser-engraved screen-printed carbon electrode (LSPCE) using drop-casting and radio frequency (RF) sputtering techniques, respectively. The surface morphology and electrochemical performance of the modified electrodes was thoroughly characterized using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDAX) electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The ZnO/MWCNT nanocomposite was successfully applied to the LSPCE electrode surface, creating a porous spongy structure with mesopores in the 2–50 nm range. The ZnO/MWCNT/LSPCE exhibited high electrocatalytic activity for glucose oxidation when tested in phosphate-buffered saline (PBS) solution with a pH of 7.4. The developed glucose biosensor demonstrated a linear detection range from 1 to 10 mM of glucose with a sensitivity of 0.068 μA mM − 1 and a detection limit of 0.43 mM. These findings indicate that the ZnO/MWCNT/LSPCE biosensor exhibits high performance in glucose detection, making it a promising candidate for practical applications in glucose monitoring. © 2024
Ahmadipour, M. ,
Bhattacharya, A. ,
Saraf bidabad, M. ,
Syuhada sazali, E. ,
Krishna ghoshal, S. ,
Satgunam, M. ,
Singh, R. ,
Rezaei ardani, M. ,
Missaoui, N. ,
Kahri, H. Clinica Chimica Acta (00098981) 554
Cancer is a complex pathophysiological condition causing millions of deaths each year. Early diagnosis is essential especially for pancreatic cancer. Existing diagnostic tools rely on circulating biomarkers such as Carbohydrate Antigen 19–9 (CA19-9) and Carcinoembryonic Antigen (CEA). Unfortunately, these markers are nonspecific and may be increased in a variety of disorders. Accordingly, diagnosis of pancreatic cancer generally involves more invasive approaches such as biopsy as well as imaging studies. Recent advances in biosensor technology have allowed the development of precise diagnostic tools having enhanced analytical sensitivity and specificity. Herein we examine these advances in the detection of cancer in general and in pancreatic cancer specifically. Furthermore, we highlight novel technologies in the measurement of CA19-9 and CEA and explore their future application in the early detection of pancreatic cancer. © 2024 Elsevier B.V.
Ahmadipour, M. ,
Saraf bidabad, M. ,
Ali, S.M.A. ,
Pang, A.L. ,
Mohd razip wee, M.F. ,
Pal, U. ,
Satgunam, M. Ceramics International (02728842) 50(24)pp. 56131-56134
Despite the excellent properties of ceramic materials for electronic devices, this study systematically investigates the significant effects of strontium (Sr2⁺) substitution on the structural, morphological, electrical, and dielectric behavior of Ca2-xSrxMgSi2O7 (x = 0, 0.2, 0.4, 0.6) ceramics. The composite was prepared via a solid-state route and characterized using techniques such as FESEM-EDAX, BET, XRD, Hall Effect measurements, and an LCR meter, respectively. The surface morphology of the structure was initiated to be smooth, compact, dense, island-shaped and porous. It is noted that the grain size reduced (from 1.10 μm to 0.72 μm) while the surface area enlarged (from 90 m2/g to 122 m2/g) with Sr substitution. XRD study showed that all the ceramics samples, after sintering at 1250 °C for 5 h. Higher amount of Sr, enhanced the crystallinity, as validated by the peak intensification. Correspondingly, the electrical resistivity and dielectric permittivity of Ca2-xSrxMgSi2O7 was decreased with Sr substitution. Particularly, the Ca1.6Sr0.4MgSi2O7 unveiled the lowermost electrical resistivity (76 Ω cm) and dielectric permittivity (εr = 848) but the uppermost dielectric loss (tan δ = 1.06) at 1 kHz. The attained outcomes exhibited the appropriateness of these samples for use in capacitor and antennas design. © 2024 Elsevier Ltd and Techna Group S.r.l.
Inflammation is part of the host’s normal response to various harmful stimuli, including chemical exposure, tissue damage, infection, or contact with bacterial components, such as lipopolysaccharide (LPS); however, excessive inflammation leads to various acute and chronic human diseases. Macrophages contribute to the inflammatory process by secreting inflammatory mediators, such as prostaglandin E2 (PGE2) and nitric oxide (NO), as well as proinflammatory cytokines such as IL-1β, TNF-α and IL-6 and the excess of these mediators can be harmful to tissues and organisms. The RAW 264.7 murine macrophage cell line treated with LPS is a commonly used in vitro model for assessing anti-inflammatory efficacy. The base of conventional inflammation therapy is the use of steroidal and nonsteroidal anti-inflammatory medications, both of which have significant adverse effects. Therefore, finding new sources of less hazardous treatments is imperative. The anti-inflammatory qualities of bioactive lipids from crude extracts of the green alga Cladophora were investigated using ethanol and hexane-ether as two distinct solvents. As a result, the total lipid concentration of the hexane-ether extraction was higher, so the unsaturated fatty acids (UFAs) were extracted from this sample by the methanol-solvent crystallization technique at low temperatures. The presence of various fatty acids and their percentage purity were determined by gas chromatography (GC). After the elimination of 49.11% of the saturated fatty acids, the spontaneous nanoemulsification approach was applied to improve the stability and functionalization of the fatty acids. The nanoemulsion particles’ size, distribution, and stability were evaluated using a Zetasizer system. The mean particle size and zeta potential value were 194.3 nm and −25.8 mV, respectively. Finally, the MTT (thiazolyl blue tetrazolium bromide) assay was used to determine the toxicity of the extracted bioactive lipids in the macrophage cell line RAW264.7 for 24 h, and the results showed an increase in the viability of cells treated with UFAs after encapsulation. The IC50 values calculated from the MTT assay results for each formulation and the anti-inflammatory effects of each formulation (at 1/3 IC50 value) were determined in LPS-stimulated RAW 264.7 macrophages by performing nitric oxide (NO) and cytokine enzyme-linked immunosorbent assays. Nanoemulsions of polyunsaturated fatty acids inhibited the production of NO and interleukin 6, which may be promising candidates for biological and medical applications to combat inflammation. © World Scientific Publishing Company.
Molecular Biology Reports (03014851) 51(1)
Despite recent advancements in the treatment of metastatic castrate-resistant prostate cancer (mCRPC), this disease remains lethal. A novel family of targeted pharmaceuticals known as poly-ADP-ribose polymerase (PARP) inhibitors has been developed to treat mCRPC patients with homologous recombination repair (HRR) gene alterations. The FDA recently approved olaparib and rucaparib for treating mCRPC patients with HRR gene alterations. Ongoing trials are investigating combination therapies involving PARP inhibitors combined with radiation, chemotherapy, immunotherapy, and androgen receptor signaling inhibitors (ARSIs) to improve the effectiveness of PARP inhibitors and broaden the range of patients who can benefit from the treatment. This review provides an overview of the development of PARP inhibitors in prostate cancer and analyzes the mechanisms underlying their resistance. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.
Ahmadipour, M. ,
Ardani, M.R. ,
Saraf bidabad, M. ,
Missaoui, N. ,
Satgunam, M. ,
Singh, R. ,
Kahri, H. ,
Pal, U. ,
Pang, A.L. ,
Iqbal, M.S. Environmental Science and Pollution Research (09441344) 31(19)pp. 27770-27788
The objective of this research is to create a highly effective approach for eliminating pollutants from the environment through the process of photocatalytic degradation. The study centers around the production of composites consisting of CaCu3Ti4O12 (CCTO) and reduced graphene oxide (rGO) using an ultrasonic-assisted method, with a focus on their capacity to degrade ibuprofen (IBF) and ciprofloxacin (CIP) via photodegradation. The impact of rGO on the structure, morphology, and optical properties of CCTO was inspected using XRD, FTIR, Raman, FESEM, XPS, BET, and UV–Vis. Morphology characterization showed that rGO particles were dispersed within the CCTO matrix without any specific chemical interaction between CCTO and C in the rGO. The BET analysis revealed that with increasing the amount of rGO in the composite, the specific surface area significantly increased compared to the CCTO standalone. Besides, increasing rGO resulted in a reduction in the optical bandgap energy to around 2.09 eV, makes it highly promising photocatalyst for environmental applications. The photodegradation of IBF and CIP was monitored using visible light irradiation. The results revealed that both components were degraded above 97% after 60 min. The photocatalyst showed an excellent reusability performance with a slight decrease after five runs to 93% photodegradation efficiency. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
ACS Omega (24701343) 7(32)pp. 28421-28433
Saponins are plant glycosides with different structures and biological activities, such as anticancer effects. Ziziphus spina-christi is a plant rich in saponin, and this compound is used to treat malignant melanoma in the present study. Nanophytosomes can be used as an advantageous nanodrug delivery system for plant extracts. The aim of this work is to use the saponin-rich fraction (SRF) from Z. spina-christi and prepare SRF-loaded nanophytosomes (saponinosomes) and observe the in vitro and in vivo effects of these carriers. First, the SRF was obtained from Z. spina-christi by a solvent-solvent fractionation method. Then, Fourier transform infrared (FTIR) analyses were performed to confirm the presence of saponins in the extracted material. Subsequently, the saponinosomes were prepared by the solvent injection method (ether injection method) using a 1:1:1 ratio of lecithin/cholesterol/SRF in the mixture. Characterization of the prepared saponinosomes was performed by FTIR, dynamic light scattering (DLS), field-emission scanning electron microscopy (FE-SEM), and atomic force microscopy (AFM) analyses. In addition, a UV-vis spectrophotometer was used to determine the entrapment efficiency (EE) and in vitro release of the SRF. Finally, cell cytotoxicity of the different formulations was evaluated using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay on both mouse melanoma cells (B16F10) and fibroblasts (L929). Using DLS, AFM, and FE-SEM analyses, the particle size was determined to be 58 ± 6 nm with a zeta potential of -32 ± 2 mV. The calculated EE was 85 ± 3%. The results of the in vitro release profile showed that 68.2% of the SRF was released from the saponinosome after 48 h. The results of the MTT assay showed that the SRF and saponinosomes have high toxicity on B16F10 melanoma cells, but saponinosomes showed a significant decrease in cytotoxicity on L929 fibroblast cells compared with that of the SRF. Our results indicate that the SRF from Z. spina-christi has anticancer activity, and the saponinosomes prepared in this work can control tumor growth, improve therapeutic efficacy, and reduce the side effects of saponins. © 2022 American Chemical Society. All rights reserved.
Eslami-kaliji, F. ,
Saraf bidabad, M. ,
Kiani-esfahani, A. ,
Mirahmadi-zare, S.Z. ,
Dormiani, K. Journal of Biomedical Materials Research - Part A (15493296) 109(9)pp. 1575-1587
Dendritic cells (DCs), in response to the biomaterials, utilize toll-like receptors (TLRs) to become mature or tolerogenic through TLRs-dependent signaling pathways, especially TLR4. Regarding the physicochemical properties of biomaterials, some of such signaling pathways are activated. Unsaturated fatty acids have been explored as an antagonist for TLRs and lead to the tolerogenic phenotype of DCs. Here we showed that, although cultured DCs on both chitosan and Alginate-polyethyleneimine (Alg-PEI) films became fully mature, 10-hydroxy-2-decanoic acid (10-HDA), an unsaturated fatty acid found in royal jelly, led to the tolerogenic immunophenotype of DCs on both films. The cultured cells on the films possessed iDCs-like morphology in the presence of 10-HDA. Moreover, 10-HDA expressed lower levels of CD80, CD83, CD86, and HLA-DR, a higher level of IL-10, and lower level of IL-12 in the cultured DCs on both films. Furthermore, HEK293T cells expressing only TLR4 (HEK-TLR4 cells) were co-cultured with LPS, a specific agonist for TLR4, and 10-HDA. The 10-HDA significantly reduced the expression of tumor necrosis factor-a (TNF-α) in the HEK-TLR4 cells compared to treated only with LPS. These findings indicate that the 10-HDA acts as an antagonist of TLR4; therefore, potentially can be used in autoimmune diseases and preventing the rejection of biomaterials implantation and allograft transplantation. © 2021 Wiley Periodicals LLC
Journal Of Medical Signals And Sensors (22287477) 10(1)pp. 35-41
Background: Material selection is a key issue for the fabrication of non-enzymatic electrode in glucose biosensors. Metallic glass (MG) as an advanced innovative material can provides many basic structural requirements of electrodes. A novel non-enzymatic biosensor based on Ti57Cu28{Zr0.95-Hf0.05}XSi15-XMG (Ti-MG) thin film was introduced for glucose oxidation. Methods: The Ti-MG thin film was deposited on the carbon substrate of screen-printed carbon electrode (SPCE), and the Ti-MG modified SPCE was fabricated as Ti-MG/SPCE. The morphology and structure of the Ti-MG thin film were characterized by field emission scanning electron microscope and X-ray diffraction. Electrochemical evaluations were studied by electrochemical impedance spectroscopy and cyclic voltammetry. Results: The Ti-MG was sputtered on the carbon substrate in the form of a porous spongy thin film with 285 nm thickness and nanoparticles with average diameter size of 110 nm. The Ti-MG/SPCE showed low charge transfer resistance to the electron transfer and high electrocatalytic activity toward the oxidation of glucose in PBS (pH = 7.4) solution. This biosensor exhibited good analytical performance with a linear range from 2 to 8 mM glucose and sensitivity of 0.017 μA mM-1. Conclusion: The experimental results indicate that Ti-MG thin film has a high ability to electron transfer and glucose oxidation for the development of non-enzymatic glucose biosensors. © 2020 Isfahan University of Medical Sciences(IUMS). All rights reserved.
ACS Biomaterials Science and Engineering (23739878) 6(5)pp. 2726-2739
Various subtypes of immunocytes react against implanted biomaterials to eliminate the foreign body object from the host's body. Among these cells, dendritic cells (DCs) play a key role in early immune response, later engaging lymphocytes through antigens presentation. Due to their capability to induce tolerogenic or immunogenic responses, DCs have been considered as key therapeutic targets for immunomodulatory products. For instance, tolerogenic DCs are applied in the treatment of autoimmune diseases, rejection of allograft transplantation, and implanted biomaterial. Due to the emerging importance of DCs in immunomodulatory biomaterials, this Review summarizes DCs' responses-such as adhesion, migration, and maturation-to biomaterials. We also review some examples of key molecules and their applications in DCs' immunoengineering. These evaluations would pave the way for designing advanced biomaterials and nanomaterials to modulate the immune system, applicable in tissue engineering, transplantation, and drug delivery technologies. Copyright © 2020 American Chemical Society.
Journal of Isfahan Medical School (10277595) 38(564)pp. 85-98
Obesity is always associated with chronic (low-grade) inflammation, which causes insulin-resistance in type-II diabetes mellitus. Dramatically, cholesterol level rises with starting diabetes and lower insulin level. With this increment, the statistical observations indicate a high risk of vascular diseases such as atherosclerosis. Therefore, the direct relationship between these complications, which is known to be the most important cause of mortality in these patients, has led scientists to take a serious and effective look at developing strategies and methods for controlling the inflammation of the immune system. Recent findings in the field of medicinal herbals and ingredients has shown that their macromolecules, due to specific structures and viability, have a potential impact on immune function of various aspects such as controlling inflammation, and modification or suppression of specific performance; using of those medicinal plants is emphasized by the World Health Organization, too. The global extensive studies about immunological effects of plant extracts such as Saponin molecules in cedar leaf extract have led to the discovery of compounds with amazing anti-inflammatory effects. Research conducted in Iran and elsewhere on plants containing active ingredient Saponins Christine A has shown that this group of plant molecules, as significant inhibitor of phosphorylation complex, with inhibition of inhibitor I?Bα nuclear factor kappa B (I?Bα-NF-?b), cause to modulate the induction of inducible nitric oxide synthase (iNOS) gene expression in the cytoplasm. Moreover, by disrupting the nitric oxide equilibrium in inflammatory environments, it can relieve mild tissue inflammation, which can improve obesity related to type-II diabetes mellitus and its complications. As an overall assessment of the reviewed studies, it can be concluded that the Saponins, especially molecules Saponins Christine A, can be considered seriously as a natural proimmuno-drug in treatment of inflammation of mild chronic obesity in type-II diabetes, and related complications such as insulin resistance, type-II diabetes, hypercholesterolemia, and arteriosclerosis. © 2016 Isfahan University of Medical Sciences(IUMS). All rights reserved.
Polymer Bulletin (14362449) 76(11)pp. 5717-5731
In this paper, the tunneling effect as the main mechanism for charge transferring in polymer/carbon nanotubes (CNT) nanocomposites (PCNT) is correlated with interphase percolation. Soft-core and hard-core models express the percolation threshold based on a previous report. Furthermore, the tunneling effect is related to the interphase layer around the nanoparticles and the excluded volume and percolation threshold are defined for this case. The calculations of all models are compared to the experimentally measured percolation threshold in some samples. The predictions of soft-core and hard-core approaches deviate from the low percolation threshold in PCNT. It is found that the model assuming the interphase as tunneling distance can properly describe the low level of percolation threshold in PCNT. Based on this model, the effects of main parameters on the percolation threshold and the electrical conductivity of PCNT are described. The predictions demonstrate that the thin and long CNT together with the thick interphase show positive impacts on the percolation threshold and conductivity. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Journal of Cluster Science (15728862) 30(1)pp. 61-67
The reduction mechanisms of N2O on surfaces of P-doped carbon nanocone (CNC) and Si-doped boron nitride nanocone (BNNC) were investigated by using of density functional theory. The adsorption energies of P and Si on surfaces of CNC and BNNC were − 293.1 and − 325.7 kcal/mol, respectively. The decomposition of CNC-P–N2O and BNNC-Si–N2O and reduction of CNC-P–O* and BNNC-Si–O* by using of the CO molecule were investigated. Results show that BNNC-Si–O* has lower activation energy and higher ∆Gad than CNC-P–O*. Results show that activation energy for BNNC-Si–O* + N2O → BNNC-Si–O2 + N2 and CNC-P–O* + N2O → CNC-P–O2 + N2 reactions were 32.56 and 36.78 kcal/mol, respectively. The results show that P-doped CNC and Si-doped BNNC can be potential catalysts to reduction of N2O. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
RSC Advances (20462069) 8(42)pp. 23825-23834
In this paper, the Kolarik model for the tensile modulus of co-continuous blends based on cross-orthogonal skeleton structures is simplified and developed for polymer/carbon nanotube (CNT) nanocomposites assuming continuous CNT networks in the polymer matrix and the reinforcing and percolating efficiencies of the interphase. For this purpose, the Ouali model for the modulus of nanocomposites above the percolation threshold is linked with the Kolarik model and the interphase percolation is considered with the excluded volume of the nanoparticles. In addition, the simplified Kolarik model is developed with the interphase as a new phase surrounding the nanofiller. A good agreement between the experimental data and the predictions is observed in the samples containing interphases and filler networks, while the developed model cannot estimate the modulus in the absence of interphases and network structures. The developed model demonstrates the effects of all the parameters on the modulus. The interphase parameters more significantly affect the modulus compared to the concentration and modulus of the filler, demonstrating the importance of the interphase properties. © The Royal Society of Chemistry 2018.
New Journal of Chemistry (11440546) 42(16)pp. 13674-13683
In the present study, a novel double layer film (DLF) composed of Rose Bengal dye and reduced graphene oxide (RB/rGO-DLF) was fabricated via a facile combined (ultrasonic-spin coating) method as a silver(i) ion sensor in an aqueous environment. Microscopic and spectroscopic characterizations confirmed the successful synthesis of RB/rGO-DLF. The morphological results of FE-SEM and AFM studies confirmed the monotonous and uneven surface of the RB/rGO-DLF. Moreover, XPS analysis also proved the reaction between silver ions and Rose Bengal immobilized on the rGO structure using binging energy (B.E.). Leaching of the chemosensor was studied and the results suggest that the prepared chemosensor is constant during the sensing process without any considerable variation in its critical characteristic properties such as sensitivity, selectivity and response time. The UV-vis spectra showed the presence of two different peak intensities at 520 and 557 nm. The first peak can be attributed to the Ag-RB combination with a response time of 5 minutes at pH 7. The sensing calibration plot exhibits a linear range between 8.53 × 10-7 and 3.39 × 10-6 mol L-1 of silver ions with a linear equation of absorbance = 0.116 [Ag+] - 0.088 and a correlation coefficient of 0.987. The limit of detection (LOD) based on 3 sigma of the blank is 9.55 × 10-8 M. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Chemistry and Physics of Lipids (18732941) 214pp. 46-57
Micellization phenomenon occurs in natural and technical processes, necessitating the need to develop predictive models capable of predicting self-assembly behavior of surfactants. A least squares support vector machine (LSSVM) based quantitative structure property relationships (QSPR) model is developed in order to predict critical micelle concentration (CMC) for sugar-based surfactants. Model development is based on training and validating a predictive LSSVM strategy using a comprehensive data base consisting of 83 sugar-based surfactants. Model's reliability and robustness has been evaluated using different visual and statistical parameters, revealing its great predictive capabilities. Results are also compared to previously reported best multi-linear regression (BMLR) based QSPR and group contribution based models, showing better performance of the proposed LSSVM-based QSPR model regarding lower RMSE value of 0.023 compared to the group contribution based and the best results from BMLR-based QSPR. © 2018 Elsevier B.V.
Journal of the Mechanical Behavior of Biomedical Materials (18780180) 86pp. 368-374
In this paper, Kolarik model for tensile modulus of co-continuous blends is developed to predict the storage modulus of poly (lactic acid) (PLA)/poly (ethylene oxide) (PEO)/carbon nanotubes (CNT) nanocomposites at low frequencies (solid-like region). The storage moduli of prepared samples are obtained by frequency sweep test and Kolarik model is expanded assuming the characteristics of interphase regions and CNT networks. The developed model takes into account the percolation threshold, the percentage of networked CNT and the volume fraction of interphase regions in the networks. The calculations of developed model are compared to the experimental data and the significances of main parameters on the storage modulus are justified. The calculations successfully agree with the experimental data at different PLA and CNT concentrations. The addition of CNT thickens and strengthens the interphase regions in the samples, but the different concentrations of PLA differently affect the properties of interphase regions. A thick and strong interphase enhances the storage modulus of nanocomposites. The high fraction of networked CNT and the significant modulus of nanoparticles considerably promote the storage modulus, but only small networks cause poor storage modulus for nanocomposites. © 2018
International Journal of Biological Macromolecules (01418130) 118pp. 1494-1500
MnS2, MnS2/Chitosan‑sodium Alginate (MnS2/CS-NaAlg) and MnS2/Chitosan-Calcium Alginate (MnS2/CS-CaAlg) nanocomposites were prepared via the chemical procedure. The characterization was performed by various instruments such as energy dispersive X-ray spectrometer (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) elemental map analysis, Fourier transform infrared spectrometry (FT-IR), Brunauer–Emmett–Teller (BET) surface area measurements, UV–Vis absorption spectra and X-ray absorption spectroscopy. The mean crystallite sizes of MnS2, MnS2/CS-NaAlg and MnS2/CS-CaAlg are 60.12, 71.25 and 74.54 nm, respectively. From Kubelka–Munk equation, the energy band gaps of MnS2, MnS2/CS-NaAlg and MnS2/CS-CaAlg are estimated to be 2.83, 2.71 and 2.41 eV, respectively. The investigation of photocatalysis properties was performed by degradation of tramadol under UV light illumination. The optimum of experimental variables such as pH and time on photo-degradation were found 3 and 60 min, respectively. The results show that the efficiency photocatalysis of MnS2/CS-NaAlg and MnS2/CS-CaAlg nanocomposites under was higher than MnS2. The antibacterial and fungicidal property of MnS2/CS-NaAlg and MnS2/CS-CaAlg nanocomposites was investigated and demonstrates good efficiency in antimicrobial efficiency compared to MnS2. The MnS2, MnS2/CS-NaAlg and MnS2/CS-CaAlg have been shown excellent mechanical and antioxidant properties. © 2018
Surfaces and Interfaces (24680230) 8pp. 219-224
Subsequent host tissue responses to implanted biomaterials that occur immediately after implantation are highly determined by surface events between tissue-implant interfaces and in contact biological fluids. These events are directly affected by biomaterial surface features. The surface of the 304 stainless steel as a high used metallic biomaterials in blood contact medical devices need to hemocompatibility improvement. The hemocompatibility features of the surface are affected by various factors, including physical and chemical properties, particularly wettability. A high level of surface hydrophobicity helps to enhance the hemocompatibility. For this, many surface engineering techniques are used to modify and control surface wettability behavior that can be adapted to improve the hemocompatibility and overall performance of biomaterials. In the present study, a laser patterning model is applied for creation of parallel micro-grooves on the surface of 304 stainless steel in first stage. Secondly, a fluorocarbon thin film has been deposited on the inscribed surface of the steel using polytetrafluoroethylene (PTFE) sputtering. The results show that, by creating a micro-groove pattern on the steel surface, the wettability behavior of the surface will also change and the contact angle will be increased from 80° to almost 111°. Moreover, the deposition of a polymer thin film has led to a decrease in surface energy and, thereby, an increase in hydrophobicity and making a contact angle of 149°. From these finding, it can be concluded that, with simultaneous use of topography and surface chemistry changes, the wettability behavior of the surface has been increased and a high and appropriate level of hydrophobicity has been achieved consequently, that is suitable for hemocompatibilty of blood-contact devices. © 2017 Elsevier B.V.
Computers in Biology and Medicine (00104825) 81pp. 159-166
Background Implant loosening may occur after dental implant placement as a result of the mechanical conditions created around the implant. In this research, the effect of bone drilling conditions on the magnitude of stress created in newly-formed bone around the implant, after placement, was investigated using FEA analysis. Method The simulations performed in this study were based on the three-dimensional (3D) shape of the created cavities, extracted from the drilled cortical bone of the jaws. With this aim, a dental implant model was placed in the jaw and a shell of the 3D bone cavity remained as a newly-formed cortical bone after implant placement. Then, a load was exerted on the implant model and the value of stress created on the newly-formed bone was obtained. Overall, eight combined models were used in all the eight drilling and loading simulations. The examined variables were rotational speed of drill bit, its feed rate and head angle. Also, an animal test was performed to investigate the accuracy of the simulation results. Results The results of this study showed that the amount of principal stress was the least (16.7 MPa) for a newly-formed cortical bone whose cavity was created under drilling condition at the same head angle and feed rate of the drill bit with a rotational speed of 400 rpm. The same results were obtained for the head angle and feed rate of a drill bit of 70° and 1.5 mm/s, respectively. Conclusions Drilling conditions have effect on the stress created in a newly-formed cortical bone after dental implant loading. © 2017 Elsevier Ltd
British Journal of Oral and Maxillofacial Surgery (15321940) 54(4)pp. 400-404
The main factors that cause an increase in the temperature of the jaw during drilling when implanting teeth are the geometric measurements of the surgical drill, its rotational speed, and its feed rate (cutting speed). Using finite element modelling we analysed the effect of the three variables - the angle of the head of the drill bit, the rotational speed, and the feed rate - on the increase in the temperature of the bone at the point of the drill. This showed that drilling with the angle of the head of the drill bit at 70° generates a lower temperature than when it is at 90° or 118°. The same is true when the drill bit is set at 200 rotations/minute (rpm) compared with 400,800, or 1200 rpm. When the feed rate of the drill bit is 120 mm/minute it generates less heat than when it is at 90 or 60 mm/minute. An increase in temperature during drilling of the jaw has a direct relation with the rotational speed of the drill bit, and a reverse relation to its feed rate. The sharper the drill bit, the lower the temperature during drilling. © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Indian Journal of Science and Technology (discontinued) (09746846) 9(6)
Background/Objectives: Corrosion causes complications such as toxicity and inflammation by making changes in metals, fracture, relaxation and loss of implant strength. In biomaterial science, we try to select and combine materials to construct and design the implants that have less corrosion and consequently reduce complications as much as possible. Methods/ Statistical analysis: In this study, Zirconium-2.5 Niobium alloy was heat-treated to remove its residual stress after rolling operations. Surface oxides were diagnosed by XPS analysis on the desired alloy which had been kept for two years in Ringer's solution. To measure the corrosion rate parameter on the desired sample, corrosion test was conducted using a three-electrode cell method. Findings: Surface oxides Nb2O5 and ZrO2 were diagnosed by XPS analysis. The results showed that the corrosion rate in this alloy was less than the usual corrosion rate of Titanium implant and its alloys. Application/ Improvements: Biocompatible oxides alongside high in vitro corrosion make Zr-2.5Nb alloy as favorable surgical implants.
Journal Of Reports In Pharmaceutical Sciences (23225106) 5(2)pp. 94-103
The most famous artificial polymers for cartilage regeneration constructs are poly lactic acid (PLA, which is present in both L and D forms), poly-glycolic acid (PGA), and their copolymer poly-lactic-co-glycolic acid (PLGA). PLGA shows high biocompatibility, a potential to break down into safe monomer units, a beneficial range of mechanical characteristics, and governable degradation time depending on the copolymer ratio. In this review we critically focused on PLGA applications such as scaffolds and carriers for bioactive agents such as drugs, growth factors, and other bioactive molecules in order to safely delivering to cartilage tissue for reconstructing articular cartilage (AC) defects. © 2016 by Kermanshah University of Medical Sciences.
Thin Solid Films (00406090) 574pp. 189-195
Surface modification of ordinary alloys by advanced coating provides a means to maintain the bulk properties of the alloy and thereby its utility in sensitive applications. In this paper, we describe the deposition of a Ti-based metallic glass thin film on 316 L stainless steel using a high vacuum pulse laser deposition (HVPLD) process without a bulk metallic glass (MG) source as target. A predominant amorphous single phase film was obtained in the proper chemical composition (Ti57Cu28{Zr0.95-Hf0.05}5Si10) by controlling several process parameters, including the target rotation speed and vacuum pressure. Our HPLD configuration entailed high vacuum pressure (less than 13.3 × 10-6 Pa), a target rotation speed in the range of 1500-2000 rotation per minute (rpm) and a substrate temperature between 450 and 600°C. These parameters provide excellent control over the amorphicity of the filmmatrix. Ourwork opens up interesting opportunities to improve the poor surface properties of metallic alloys specially biometallic alloys by depositing a thin film of Ti-based MG on their surface, which can also overcome the problem of MG bulk form production as we just deposited a thin film of MG. © 2014 Elsevier B.V. All rights reserved.
