Nanoscience & Technology
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Program Overview
If you enjoy laboratory work and have the desire to apply your scientific skills to the latest technologies that shape our world, then this may be the right path for you.
Do you enjoy…
- Going into the nano world to understand the basic unit of anything and investigate, design and invent new structures and materials out of it?
- Carrying out laboratory experiments and data analysis?
- Getting to grips with the latest research in Nanoscience and its impact on technology?
If yes, then you should consider joining this new and unique program at GU.
What Is Nanoscience?
Nanoscience and Technology program is an interdisciplinary science program designed for students interested in developing and manipulating materials at the molecular level. In the first two years students will build strong background in basic sciences; Physics, Chemistry and Biology before getting more specialized during the last two years in the field of study of their own choice. This will enrich their knowledge and allow them to work independently or within multidisciplinary teams .
Nanotechnology is the study of any science at the nanoscale. It is a big umbrella that covers wide range of applications.For instance, Nanomedicine produces nanomaterials such as gold nanorods, nanofibers to help cure disease. Nanoelectronics develop all smart electronics that we use these days from phones and computers to medical robots that can invade our bodies to perform surgical operations. Food and agricultural industry that use novel nanosized products to improve food product quality and features.
Nanotechnology proved to be capable of affecting everything in our life. It has applications that is involved in energy generation, drug synthesis and development, food industry, fabric and cloth production, hair dyes and beauty industry, beds and bedding improvement. It has an impact on everything in our day to day life.
- If you’re looking for a program which will prepare you for a successful career at the forefront of the ‘Fourth Industrial Revolution’ , then this could be exactly what you’re looking for. You’ll explore the incredible potential of the nanoworld either by creating nanocapsules that are strong enough to kill cancer cells or produce very light weight airplane using ‘wonder materials’ like graphene (200 times stronger than steel, yet just one atom thick) and how these nanomaterials are set to revolutionize everything from computing to aerospace.
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- PublicationOpen AccessOn structure of discrete Muckenhoupt and discrete Gehring classes(Springer Nature, 2020-10-16) Rabie, S. S.; AlNemer, Ghada; Zakarya, M.; Saker, Samir H.In this paper, we study the structure of the discrete Muckenhoupt class Ap(C) and the discrete Gehring class Gq(K). In particular, we prove that the self-improving property of the Muckenhoupt class holds, i.e., we prove that if u∈Ap(C) then there exists q
1 . The relation between the Muckenhoupt class A1(C) and the Gehring class is also discussed. For illustrations, we give exact values of the norms of Muckenhoupt and Gehring classes for power-low sequences. The results are proved by some algebraic inequalities and some new inequalities designed and proved for this purpose.
- PublicationOpen AccessEffect of pH and zeta potential of Pickering stabilizing magnetite nanoparticles on the features of magnetized polystyrene microspheres(Wiley, 2020-11-03) Shalan, Ahmed Esmail; Mohamed, Lamiaa A.; Essawy, Hisham A.; Taha, Fouad; Dyab, Amro K. F.; Abd El-Mageed, Ahmed I. A.Styrene as a monomer was emulsified in water using several magnetite nanoparticles concentration and pH values. Emulsified styrene drops were used as templates for polymerization, in presence of water soluble free radical initiator, and formation of composite particles. Styrene template drops stabilization was verified by light as well as scanning electron microscopy imaging, which ensured the participation of the particles in building up a mechanical barrier to stop oil drops coalescence. Furthermore, the produced polystyrene composites were strongly attracted to an external magnet. The difference in particles size as a function of pH was elucidated using zeta potential measurements, which indicated dominance of pH on the hydrophilicity of the particles and consequently the extent of emulsification, which in turn affected the size of the obtained microspheres. Under some circumstances, capsules were formed instead of particles. Thereby, it can be concluded that the magnetic microspheres are optimally formed at pH 2.3 independently of the magnetite content used.
- PublicationOpen AccessHorizon: Microfluidic platform for the production of therapeutic microbubbles and nanobubbles(AIP, 2021) Abou-Saleh, Radwa; Armistead, Fern J.; Batchelor, Damien V. B.; Johnson, Benjamin R. G.; Peyman, Sally A.; Evans, Stephen D.Microbubbles (MBs) have a multitude of applications including as contrast agents in ultrasound imaging and as therapeutic drug delivery vehicles, with further scope for combining their diagnostic and therapeutic properties (known as theranostics). MBs used clinically are commonly made by mechanical agitation or sonication methods, which offer little control over population size and dispersity. Furthermore, clinically used MBs are yet to be used therapeutically and further research is needed to develop these theranostic agents. In this paper, we present our MB production instrument “Horizon,” which is a robust, portable, and user-friendly instrument, integrating the key components for producing MBs using microfluidic flow-focusing devices. In addition, we present the system design and specifications of Horizon and the optimized protocols that have so far been used to produce MBs with specific properties. These include MBs with tailored size and low dispersity (monodisperse); MBs with a diameter of ∼2 μm, which are more disperse but also produced in higher concentration; nanobubbles with diameters of 100–600 nm; and therapeutic MBs with drug payloads for targeted delivery. Multiplexed chips were able to improve production rates up to 16-fold while maintaining production stability. This work shows that Horizon is a versatile instrument with potential for mass production and use across many research facilities, which could begin to bridge the gap between therapeutic MB research and clinical use.
- PublicationOpen AccessEffect of Unit-Cell Size on the Barely Visible Impact Damage in Woven Composites(MDPI, 2021) El-Dessouky, Hassan M.; Saleh, Mohamed Nasr; Wang, Ying; Alotaibi, Mohamed S.The effect of the weaving architecture and the z-binding yarns, for 2D and 3D woven composites on the low-velocity impact resistance of carbon fibre reinforced composites, is investigated and benchmarked against noncrimp fabric (NCF). Four architectures, namely: NCF, 2D plain weave (2D-PW), 3D orthogonal: plain (ORT-PW) and twill (ORT-TW), were subjected to 15 J impact using a 16 mm-diameter, 6.7 kg hemispherical impactor. Nondestructive techniques, including ultrasonic C-scanning, Digital Image Correlation (DIC), and X-ray computed tomography (CT) were used to map and quantify the size of the induced barely visible impact damage (BVID). The energy absorption of each architecture was correlated to the damage size: in both in-plane and in-depth directions. The 3D architectures, regardless of their unit-cell size, demonstrated the highest impact resistance as opposed to 2D-PW and the NCF. X-ray CT segmentation showed the effect of the higher frequency of the z-binding yarns, in the ORT-PW case, in delamination and crack arresting even when compared to the other 3D architecture (ORT-TW). Among all the architectures, ORT-PW exhibited the highest damage resistance with the least damage size. This suggests that the accurate design of the z-binding yarns’ path and more importantly its frequency in 3D woven architectures is essential for impact-resistant composite structures.
- PublicationOpen AccessSome new dynamic inequalities with several functions of Hardy type on time scales(Springer Nature, 2021-01-04) Hamiaz, Adnane; Abuelela, Waleed; Baleanu, Dumitru; Saker, Samir H.The aim of this article is to prove some new dynamic inequalities of Hardy type on time scales with several functions. Our results contain some results proved in the literature, which are deduced as limited cases, and also improve some obtained results by using weak conditions. In order to do so, we utilize Hölder’s inequality, the chain rule, and the formula of integration by parts on time scales.
- PublicationOpen AccessOn Cesàro and Copson sequence spaces with weights(Springer Nature, 2021-01-04) Abuelwafa, Maryam M.; Zidan, Ahmed M.; Baleanu, Dumitru; Saker, Samir H.In this paper, we prove some properties of weighted Cesàro and Copson sequences spaces by establishing some factorization theorems. The results lead to two-sided norm discrete inequalities with best possible constants and also give conditions for the boundedness of the generalized discrete weighted Hardy and Copson operators.
- PublicationMetadata onlySpectroscopic ellipsometry and morphological studies of nanocrystalline NiO and NiO/ITO thin films deposited by e-beams technique(Elsevier, 2021-02) Ismail, Mohamed Emam; El-Hagary, M.; H.M. El-Sherif, H.M.; El-Naggar, Abeer M.; El-Nahass, M.M.The current article reported new data on the structural, surface morphology, and optical properties of multi-thickness nanocrystalline NiO/glass substrate and NiO/ITO/glass substrate semiconductor thin films prepared by the electron beam deposition technique. Structural investigation shows that the as-deposited multi-thickness NiO films deposited on a glass substrate crystallize in a cubic NaCl-type structure. However, ITO thin film has a cubic-type structure. Besides, the increase in the crystallite size was observed with increasing the thickness of NiO film, this behavior was confirmed by AFM micrographs. In the spectral range 280 nm–1800 nm, the optical properties of the NiO/glass substrate and NiO/ITO/glass substrate thin films have been investigated using the spectroscopic ellipsometry (SE) technique. For NiO/glass substrate sample, the SE results provide direct energy Edir g ≈ 3.954 eV, indirect energy Eindir g ≈ 2.855eV and phonon energy of order 200 meV. In addition, the analysis of the refractive index dispersion gives the atomic number density to be Nfij = 2.213x1022cm− 3. On the other hand, for the NiO (410 nm)/ITO (99 nm)/glass substrate thin film sample, a reduction in the direct transition energy to Edir g ≈ 3.24eV and also in the factor Nfij to 1.6x1022cm− 3 was observed. Additionally, the values of the oscillator parameters were calculated for NiO/glass substrate and NiO/ITO/glass substrate thin films using the Wemple-DiDomenico single oscillator model (WDD). Finally, it was found that the values of Urbach energy for NiO/ glass substrate and NiO (410 nm)/ITO (99 nm)/glass substrate are minimal relative to the energy gap values which indicates that the region of localized states is very narrow compared to the width of the energy gap.
- PublicationOpen AccessProperties of a Generalized Class of Weights Satisfying Reverse Hölder’s Inequality(Hindawi, 2021-02-23) Rabie, S. S.; Agarwal, R. P.; Saker, Samir H.; Ismat BegIn this paper, we will prove some fundamental properties of the discrete power mean operator of order , where is a nonnegative discrete weight defined on the set of the nonnegative integers. We also establish some lower and upper bounds of the composition of different operators with different powers. Next, we will study the structure of the generalized discrete class of weights that satisfy the reverse Hölder inequality for positive real numbers , , and such that and . For applications, we will prove some self-improving properties of weights from and derive the self improving properties of the discrete Gehring weights as a special case. The paper ends by a conjecture with an illustrative sharp example.
- PublicationOpen AccessNew characterizations of weights on dynamic inequalities involving a Hardy operator(Springer Nature, 2021-04-23) Alzabut, J.; Saied, A. I.; O’Regan, D.; Saker, Samir H.In this paper, we establish some new characterizations of weighted functions of dynamic inequalities containing a Hardy operator on time scales. These inequalities contain the characterization of Ariňo and Muckenhoupt when [Math Processing Error], whereas they contain the characterizations of Bennett–Erdmann and Gao when [Math Processing Error]
- PublicationMetadata onlySuspension polymerization for fabrication of magnetic polystyrene microspheres stabilized with Hitenol BC-20(Springer, 2021-05-28) Dyab, Amro K. F.; Mohamed, Lamiaa A.; Taha, Fouad; Essawy, Hisham A.; Abd El-Mageed, Ahmed I. A.Polystyrene microspheres were prepared in magnetized form using a modified route of suspension polymerization in which a type of surface-active agent (Hitenol BC-20), that does not affect the interfacial tension significantly, was involved as stabilizer. In such a way, it helps to provide stabilization to styrene monomer drops in a micronized size into an aqueous phase while preserving the size and shape during the course of conducting the polymerization. Particularly, in case the monomer phase contained dispersed organophilic particles of iron oxide; the successful proceeding of such strategy is ensured from the produced uniform size of the microspheres and stable magnetic property. The excellent and stable ferromagnetism acquired by the spheres indicates a good distribution of a small amount of oleophilized nanoparticles. The produced polymer microspheres are expected for potential applications, i.e., diagnostic devices as well as smart materials
- PublicationMetadata onlyEnhancement of multifunctional optoelectronic and spintronic applications of nanostructured Cr-doped SnO2 thin films by conducting microstructural, optical, and magnetic measurements(Elsevier, 2021-06-07) Ismail, Mohamed Emam; Gharieb, A. Ali; Moustafa, S.H.; Mahasen, M.M.; Shaaban, E.R.; El-Hagary, M.A chemical synthesis method was used to produce Cr-doped SnO2 nanoparticles. By using the TEM technique, the nanocrystalline nature of the Sn1-xCrxO2 (0.0 ≤ x ≤ 0.1) nanopowder was confirmed. With different Cr concentrations, the electron beam deposition technique was used to deposit a series of Sn1-xCrxO2 nanocrystalline thin films on a silica substrate. X-ray diffraction (XRD), atomic force microscopy (AFM), spectroscopic ellipsometry (SE), and vibrating sample magnetometry (VSM) techniques were used to examine the physical properties of the deposited films. The nanocrystalline nature of the Sn1-xCrxO2 (0.0 ≤ x ≤ 0.1) thin film was confirmed by XRD and AFM morphology measurements. The XRD spectrum of the Sn1-xCrxO2 nanocrystalline film demonstrated a tetragonal crystal structure with no detectable extra phases. The optical measurements showed that as the Cr content increases, the direct optical energy gap Eg decreases without any sign of solubility limit up to x ≤ 0.1. The decrease in Eg is attributed to the sp-d exchange interaction. Also, the spectral behavior of the refractive index dispersion of the Cr-doped SnO2 indicates that as the Cr dopant increases, the refractive index of the deposited film also increases, which is attributed to the increase in the polarizability. Moreover, as the Cr content raises the atomic number, the density of the deposited film increases from 1.43 × 1022 cm−3 for SnO2 to 1.57 × 1022 cm−3 for Sn0·9Cr0·1O2. Further, the behavior of the refractive index dispersion of the deposited film was revealed using a single oscillator model proposed by Wemple-DiDomenico (WDD). Our calculations revealed that as the Cr concentration increases, the value of oscillator energy Eo decreases owing to the decrease in Eg, whereas the value of dispersion energy Ed increases because of the chemical structural changes such as the lattice parameters. Finally, the magnetic studies revealed that incorporating a small fraction of Cr into SnO2 produces room temperature ferromagnetism in the film, which is gradually suppressed by a further increase in Cr doping. These findings indicate that the Cr-doped SnO2 film can be recommended for optoelectronic and spintronic device applications.
- PublicationMetadata onlyLinear, non-linear optical properties and magnetic studies of spray pyrolysis nanocrystalline Sn1-xCoxO2 films for multifunctional optoelectronic and spintronic applications(Elsevier, 2021-06-12) El-Hagary, M.; Moustafa, S.H.; Amer, M.I.; Gad, G. M. A.; Ismail, Mohamed Emam; Hashem, H.In this paper, the structural, morphological, linear & non-linear optical, and magnetic properties of spray pyrolysis nanostructured Sn1-xCoxO2 thin films (0 ≤ x ≤ 0.08) were studied employing X-ray diffraction (XRD), atomic force microscope (AFM), spectrophotometric, and vibrating sample magnetometer (VSM) techniques, respectively. A tetragonal type structure was observed for films without any sign of impurities. XRD with Rietveld refinement analysis further revealed an increase in lattice parameters and unsystematic changes in crystallite size. AFM micrograph analysis shows that the surface roughness and root mean square roughness of the film are improved with increasing Co doping. Moreover, the spectrophotometry results indicate a direct optical transition for the film with an energy band gap reduces from 3.8 eV (x = 0) to 3.34 eV (x = 0.07) due to the rise in structural disorder and the increase in the density of localized states. The optical constants are calculated from the light transmission spectrum using the envelope method of Swanepoel. It is seen that the overall behavior of the refractive index n(λ) and extinction coefficient k(λ) increase with increasing of Co content. The dispersive oscillator parameters estimated from the single-oscillator Wemple–DiDomenico model were used to determine the non-linear optical parameters, such as the third-order non-linear optical susceptibility χ(3) and non-linear refractive index n2. Finally, intrinsic room temperature ferromagnetism is observed, which is interpreted based on the bound magnetic polarons model. In conclusion, Co doping in SnO2 host semiconductor nanocrystalline films enhances their optical and magnetic characteristics, making it a potential candidate for multifunctional applications like optoelectronics and spintronics devices.
- PublicationOpen AccessLinear, non-linear optical properties and magnetic studies of spray pyrolysis nanocrystalline Sn1-xCoxO2 films for multifunctional optoelectronic and spintronic applications(Elsevier, 2021-06-12) El-Hagary, M.; Moustafa, S.H.; Amer, M.I.; Gad, G. M. A.; Emam-Ismail, M.; Hashem, H.In this paper, the structural, morphological, linear & non-linear optical, and magnetic properties of spray pyrolysis nanostructured Sn1-xCoxO2 thin films (0 ≤ x ≤ 0.08) were studied employing X-ray diffraction (XRD), atomic force microscope (AFM), spectrophotometric, and vibrating sample magnetometer (VSM) techniques, respectively. A tetragonal type structure was observed for films without any sign of impurities. XRD with Rietveld refinement analysis further revealed an increase in lattice parameters and unsystematic changes in crystallite size. AFM micrograph analysis shows that the surface roughness and root mean square roughness of the film are improved with increasing Co doping. Moreover, the spectrophotometry results indicate a direct optical transition for the film with an energy band gap reduces from 3.8 eV (x = 0) to 3.34 eV (x = 0.07) due to the rise in structural disorder and the increase in the density of localized states. The optical constants are calculated from the light transmission spectrum using the envelope method of Swanepoel. It is seen that the overall behavior of the refractive index n(λ) and extinction coefficient k(λ) increase with increasing of Co content. The dispersive oscillator parameters estimated from the single-oscillator Wemple–DiDomenico model were used to determine the non-linear optical parameters, such as the third-order non-linear optical susceptibility χ(3) and non-linear refractive index n2. Finally, intrinsic room temperature ferromagnetism is observed, which is interpreted based on the bound magnetic polarons model. In conclusion, Co doping in SnO2 host semiconductor nanocrystalline films enhances their optical and magnetic characteristics, making it a potential candidate for multifunctional applications like optoelectronics and spintronics devices.
- PublicationMetadata onlyEncapsulation of folic acid (vitamin B9) into sporopollenin microcapsules: Physico-chemical characterisation, in vitro controlled release and photoprotection study(Elsevier, 2021-06-24) Mohammed, Al-Shymaa Y.; Dyab, Amro K. F.; Taha, Fouad; Abd El-Mageed, Ahmed I. A.Folic acid (FA) is a crucial vitamin for all living creatures. However, it is susceptible to degradation under pH, heat, ultraviolet (UV) and day sunlight conditions, resulting in lowering its bioavailability. Therefore, a versatile protective encapsulation system for FA is highly required to overcome its inherent instability. We report the use of the robust Lycopodium clavatum sporopollenin (LCS) microcapsules, extracted from their natural micrometer-sized raw spores, for FA microencapsulation. The physico-chemical characterisation of the LCS microcapsules are comprehensively investigated before and after the microencapsulation using SEM, elemental, CLSM, FTIR, TGA/DTG and XRD analyses, revealing a successful FA encapsulation within the LCS in an amorphous form. The phenylpropanoid acids, responsible for the UV protection and the autofluorescence of the LCS, were found in the LCS as evidenced by FTIR analysis. TGA/DTG results revealed that the hemi-cellulose and cellulose are the major component of the LCS. A controlled and sustained release of FA from FA-loaded LCS were achieved where the release profile of FA-loaded LCS was found to be pH-dependent. The percentages of cumulative FA released after 10 h at 37 ± 0.5 °C were 45.5% and 76.1% in pH 1.2 and 7.4, respectively, ensuring controlled and slow release in simulated physiological conditions. The FA release kinetic studies indicated the prevalence of the Fickian diffusion mechanism in pH 1.2, while anomalous non-Fickian transport was ascribed for FA release in pH 7.4. The in vitro cytotoxicity assay revealed that the obtained formulations were biocompatible against the human skin fibroblast (HSF) cell line. The versatile LCS microcapsules exhibited intriguing photostability for FA under UV or sunlight irradiation. Concretely, the obtained FA sustained delivery and photoprotection properties of these LCS microcapsules validate their multifunctional characteristics, opening up intriguing applications in oral and topical drug delivery as well as in food industry.
- PublicationMetadata onlyOptical and microstructural characterization of nanocrystalline Cu doped ZnO diluted magnetic semiconductor thin film for optoelectronic applications(Elsevier, 2021-06-30) Ali, Gharieb A.; Ismail, Mohamed Emam; El-Hagary, M.; Shaaban, E.R.; Moustafa, S.H.; Amer, M.I.; Shaban, H.A series of Zn1-xCuxO nanocrystalline films were deposited on a silica substrate using e-beam evaporation technology. The physical properties of the deposited film were closely examined using x-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDXS), atomic force microscopy (AFM), and spectroscopic ellipsometry (SE). The deposited film's structure revealed the formation of a hexagonal wurtzite structure, with no extra phases found. According to AFM analysis, the deposited Zn1-xCuxO (x = 0.0, 0.04, 0.08, 0.12, 0.16, and 0.2) film has nanocrystalline characteristics. The present findings show that increasing Cu content up to x ≤ 0.2 reduces the direct optical energy gap Eg from 3.286 eV (x = 0) to 2.934 eV (x = 0.2), which can be attributed to the sp-d exchange coupling. The refractive index dispersion extracted from SE analysis for Cu-doped ZnO thin films increased as the Cu dopant increased. In addition, the refractive index dispersion of the deposited film was studied using a single oscillator model proposed by Wemple-DiDomenico (WDD). It was found that the oscillator energy Eo decreases as the Cu concentration increases, while the dispersion energy Ed increases. As a result of the improvement in the optical energy band gap and the tunability of the values of the dispersive oscillator parameters Eo, Ed, n0, ε0, M-1, and M-3 with increasing Cu doping levels, Cu doped ZnO films are a good candidate for optoelectronic device applications.
- PublicationOpen AccessDesign of self-supported flexible nanostars mfe-ldh@ carbon xerogel-modified electrode for methanol oxidation(MDPI, 2021-09-13) Abdelrazek, Ghada M.; EL-Deeb, Mohamed M.; Farghali, Ahmed A.; Pérez-Cadenas, Agustín F.; Abdelwahab, AbdallaLayered double hydroxides (LDHs) have emerged as promising electrodes materials for the methanol oxidation reaction. Here, we report on the preparation of different LDHs with the hydrothermal process. The effect of the divalent cation (i.e., Ni, Co, and Zn) on the electrochemical performance of methanol oxidation was investigated. Moreover, nanocomposites of LDHs and carbon xerogels (CX) supported on nickel foam (NF) substrate were prepared to investigate the role of carbon xerogel. The results show that NiFe-LDH/CX/NF is an efficient electrocatalyst for methanol oxidation with a current density that reaches 400 mA·m−2 compared to 250 and 90 mA·cm−2 for NiFe-LDH/NF and NF, respectively. In addition, all LDH/CX/NF nanocomposites show excellent stability for methanol oxidation. A clear relationship is observed between the electrodes crystallite size and their activity to methanol oxidation. The smaller the crystallite size, the higher the current density delivered. Additionally, the presence of carbon xerogel in the nanocomposites offer 3D interconnected micro/mesopores, which facilitate both mass and electron transport.
- PublicationOpen AccessNovel oxygen-generation from electrospun nanofibrous scaffolds with anticancer properties: synthesis of PMMA-conjugate PVP–H2O2 nanofibers, characterization, and in vitro bio-evaluation tests(2021-11) Salim, Samar A.; Kamoun, Elbadawy A.; Evans, Stephen D.; Taha, Tarek H.; El-Fakharany, Esmail M.; Elmazar, Mohamed M.; Abdel-Aziz, A. F.; Abou-Saleh, Radwa; Salaheldin, TaherReleased oxygen plays a critical role in reducing destructive tumor behavior. This study aims to utilize decomposed hydrogen peroxide as an oxygen source by conjugating it with polyvinylpyrrolidone (PVP). PVP–hydrogen peroxide complex (PHP) composed of different ratios of (PVP : H2O2) (0.5 : 1, 1 : 1, 1 : 1.5, 1 : 5, and 1 : 10) were successfully synthesized. PHP complex with a ratio of 1 : 1.5 was chosen as the optimized ratio, and it was incorporated into the polymethyl methacrylate (PMMA) nanofibrous scaffold via the electrospinning technique. Results have revealed that the PMMA–10% PHP complex provided a significant morphological structure of nanofibrous scaffolds. The mechanical properties of PMMA–10% PHP nanofibers showed the most suitable mechanical features such as Young's modulus, elongation-at-break (%), and maximum strength, in addition to the highest degree of swelling. All PHP complex scaffolds released oxygen in a sustained manner. However, the PMMA–10% PHP complex gave the highest concentration of released-oxygen with (∼8.9 mg L−1, after 2.5 h). PMMA–10% PHP nanofibers provided an ideal model for released-oxygen scaffold with anti-cancer effect and high selectivity for cancer cells, especially for breast cancer cells. Nanofibrous scaffolds with different composition revealed high cell viability for normal cells. Such outcomes support the suitability of using synthesized nanofibrous scaffolds as released-oxygen biomaterials to enhance cancer cells' sensitivity and maximize the treatment effect.
- PublicationOpen AccessMercaptopurine-Loaded Sandwiched Tri-Layered Composed of Electrospun Polycaprolactone/Poly(Methyl Methacrylate) Nanofibrous Scaffolds as Anticancer Carrier with Antimicrobial and Antibiotic Features: Sandwich Configuration Nanofibers, Release Study and in vitro Bioevaluation Tests(Dove medical research, 2021-11-11) Salim, Samar A.; Kamoun, Elbadawy A.; Evans, Stephen D.; EL-Moslamy, Shahira H.; El-Fakharany, Esmail M.; Elmazar, Mohamed M.; Abdel-Aziz, A. F.; Abou-Saleh, Radwa; Salaheldin, Taher A.Background: 6-Mercaptopurine (6-MP) is a potential anti-cancer agent which its therapeutic and limitation applicability due to its high toxicity. Objective: Herein, 6-MP was loaded into tri-layered sandwich nanofibrous scaffold (the top layer composed of poly methyl methacrylate/polycaprolactone (PMMA/PCL), the middle layer was PCL/PMMA/6-MP, and the bottom layer was PCL/PMMA to improve its bioactivity, adjusting the release-sustainability and reduce its toxicity. Methods: Electrospun tri-layered nanofibers composed of PCL/PMMA were utilized as nano-mats for controlling sustained drug release. Four groups of sandwich scaffold configurations were investigated with alteration of (PMMA: PCL) composition. Results: The sandwich scaffold composed of 2%PCL/4%PMMA/1%6-MP showed the best miscibility, good homogeneity and produced the smoothest nanofibers and low crystallinity. All fabricated 6-MP-loaded-PCL/PMMA scaffolds exhibited antimicrobial properties on the bacterial and fungal organisms, where the cytotoxicity evaluation proved the safety of scaffolds on normal cells, even at high concentration. Scaffolds provided a sustained-drug release profile that was strongly dependent on (PCL: PMMA). As (PCL: PMMA) decreased, the sustained 6-MP release from PCL/PMMA scaffolds increased. Results established that ∼ 18% and 20% of 6-MP were released after 23h from (4%PCL/4%PMMA/1%6-MP) and (2%PCL/4%PMMA/1%6-MP), respectively, where this release was maintained for more than 20 days. The anti-cancer activity of all fabricated scaffolds was also investigated using different cancerous cell lines (e.g., Caco-2, MDA, and HepG-2) results showed that 6-MP-loaded-nanofibrous mats have an anti-cancer effect, with a high selective index for breast cancer. We observed that viability of a cancer cell was dropped to about 10%, using nanofibers containing 2%PCL/4%PMMA/1%6-MP. Conclusion: Overall, the PCL: PMMA ratio and sandwich configuration imparts a tight control on long-term release profile and initial burst of 6-MP for anticancer treatment purposes.
- PublicationOpen AccessSynergistic performance of simply fabricated polyaniline/carbon xerogel composite as supercapacitor electrode(Elsevier, 2021-11-18) Khammar, Hany; Abdel-Samad, Hesham S.; Hassan, Hamdy H.; Abdelwahab, AbdallaThis work involves preparation of loaded polyaniline (PANI)/carbon xerogel (CX) composites with different mass ratios. The effect of PANI loading on the porosity and electrochemical activity of the composites is studied. Surface characterization analysis of studied samples reveals that incorporation of PANI onto the CX network reduces its specific surface area with a simultaneous expansion of the average pore diameter from the microporous to the mesoporous range. The prepared composites are tested as supercapacitor electrodes, and their electro-capacitive properties are studied by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy in a two-electrode cell using 1 M H2SO4 electrolyte. Results show that introducing PANI into CX network enhances the gravimetric capacitance from 156 to 612 F ∙ g−1 at current density of 0.1 A ∙ g−1 with reasonable stability. For instance, sample composite of PANI:CX = 5:1 w/w displays a retention percentage of 87.6% after 1500 repetitive cycles. In general, this synergy between PANI and CX in the prepared composites is attributed to the development of mesoporosity and the lowering of electrode resistance.
- PublicationOpen AccessGrowing Tungsten Nanophases on Carbon Spheres Doped with Nitrogen. Behaviour as Electro-Catalysts for Oxygen Reduction Reaction(MDPI, 2021-12-14) Briz-Amate, Teresa; Castelo-Quibén, Jesica; Bailón-García, Esther; Abdelwahab, Abdalla; Carrasco-Marín, Francisco; Pérez-Cadenas, Agustín F.This work shows the preparation of carbon nanospheres with a high superficial nitrogen content (7 wt.%), obtained by a simple hydrothermal method, from pyrocatechol and formaldehyde, around which tungsten nanophases have been formed. One of these nanophases is tungsten carbide, whose electro-catalytic behavior in the ORR has been evaluated together with the presence of nitrogen surface groups. Both current and potential kinetic density values improve considerably with the presence of tungsten, despite the significant nitrogen loss detected during the carbonization treatment. However, the synergetic effect that the WC has with other electro-catalytic metals in this reaction cannot be easily evaluated with the nitrogen in these materials, since both contents vary in opposite ways. Nevertheless, all the prepared materials carried out oxygen electro-reduction by a mixed pathway of two and four electrons, showing remarkable electro-catalytic behavior.