Mohamed S.A. Darwish

Prof. Mohamed S.A. Darwish

Egyptian Petroleum Research Institute (EPRI), Department of Petroleum Applications, Cairo, Egypt
orcid

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
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Mohamed S.A. DarwishMohamed S.A. Darwish
Mohamed S.A. Darwish
MMMohamed H. Mostafa
Mohamed H. Mostafa
Laila Mohammad AlharbiLaila Mohammad Alharbi
Laila Mohammad Alharbi
Polymeric nanocomposites (PNC) have an outstanding potential for various applications as the integrated structure of the PNCs exhibits properties that none of its component materials individually possess. Moreover, it is possible to fabricate PNCs into desired shapes and sizes, which would enable controlling their properties, such as their surface area, magnetic behavior, optical properties, and catalytic activity. The low cost and light weight of PNCs have further contributed to their potential in various environmental and industrial applications. Stimuli-responsive nanocomposites are a subgroup of PNCs having a minimum of one promising chemical and physical property that may be controlled by or follow a stimulus response. Such outstanding properties and behaviors have extended the scope of application of these nanocomposites. The present review discusses the various methods of preparation available for PNCs, including in situ synthesis, solution mixing, melt blending, and electrospinning. In addition, various environmental and industrial applications of PNCs, including those in the fields of water treatment, electromagnetic shielding in aerospace applications, sensor devices, and food packaging, are outlined.

16 August 2019 in Nanomaterials
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Mohamed S.A. DarwishMohamed S.A. Darwish
Mohamed S.A. Darwish
HKHoHyeon Kim
HoHyeon Kim
HLHwangjae Lee
Hwangjae Lee
CRChiseon Ryu
Chiseon Ryu
JLJae Young Lee
Jae Young Lee
JYJungwon Yoon
Jungwon Yoon
Magnetic nanoparticles (MNPs) that exhibit high specific loss power (SLP) at lower metal content are highly desirable for hyperthermia applications. The conventional co-precipitation process has been widely employed for the synthesis of magnetic nanoparticles. However, their hyperthermia performance is often insufficient, which is considered as the main challenge to the development of practicable cancer treatments. In particular, ferrite MNPs have unique properties, such as a strong magnetocrystalline anisotropy, high coercivity, and moderate saturation magnetization, however their hyperthermia performance needs to be further improved. In this study, cobalt ferrite (CoFe2O4) and zinc cobalt ferrite nanoparticles (ZnCoFe2O4) were prepared to achieve high SLP values by modifying the conventional co-precipitation method. Our modified method, which allows for precursor material compositions (molar ratio of Fe+3:Fe+2:Co+2/Zn+2 of 3:2:1), is a simple, environmentally friendly, and low temperature process carried out in air at a maximum temperature of 60 °C, without the need for oxidizing or coating agents. The particles produced were characterized using multiple techniques, such as X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV–Vis spectroscopy), and a vibrating sample magnetometer (VSM). SLP values of the prepared nanoparticles were carefully evaluated as a function of time, magnetic field strength (30, 40, and 50 kA m−1), and the viscosity of the medium (water and glycerol), and compared to commercial magnetic nanoparticle materials under the same conditions. The cytotoxicity of the prepared nanoparticles by in vitro culture with NIH-3T3 fibroblasts exhibited good cytocompatibility up to 0.5 mg/mL. The safety limit of magnetic field parameters for SLP was tested. It did not exceed the 5 × 109 Am−1 s−1 threshold. A saturation temperature of 45 °C could be achieved. These nanoparticles, with minimal metal content, can ideally be used for in vivo hyperthermia applications, such as cancer treatments.

4 June 2022 in Journal of Thermal Analysis and Calorimetry
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Mohamed S.A. DarwishMohamed S.A. Darwish
Mohamed S.A. Darwish
LAL. M. Al-Harbi
L. M. Al-Harbi
ABAhmed Bakry
Ahmed Bakry
One of the main challenges in hyperthermia treatment is how to improve the heating performance of nanoparticles with high specific loss power (SLP). To tackle this challenge, magnetite nanoparticles (MNPs) and coated magnetite nanoparticles with polyvinyl alcohol (PVA@MNPs) were fabricated via ultrasonic-assisted coprecipitation technique. The obtained nanoparticles were characterized by using FT-IR, TEM, TGA, XRD, ICP-OES, DLS, zeta potential, VSM and UV–Vis spectroscopy. The self-heating properties of the MNPs and PVA@MNPs were studied under alternating magnetic strength, frequency and induction time. MNPs and PVA@MNPs showed that the nanoparticles have a nearly spherical shape ranging between 12.3 ± 3.2 and 10 ± 2.5 nm, respectively. The higher value of zeta potentials of PVA@MNPs (− 11.49 mV) implies that the nanoparticle may show good stability in aqueous solutions. The magnetization saturation values were 41.98 and 45.08 emu g−1 for MNPs and PVA@MNPs, respectively. The prepared nanoparticles showed small coercivity and a remanence magnetization due to the soft magnetic nature of the prepared nanoparticles. The highest SLP value was 163.81 W g−1 for PVA@MNPs, while the lowest SLP value was 4.84 W g−1 for MNPs under the same magnetic field condition. The presence of PVA shell improved the particle stability and the magnetization for PVA@ MNPs. This successfully caused an improvement in the heating performance and magnetic hyperthermia as well. These features make the prepared PVA@MNPs in this study applicable as hyperthermic agents for biomedical applications.

6 June 2022 in Heliyon
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Journal Article
Open access
LAL.M. Al-Harbi
L.M. Al-Harbi
Mohamed S.A. DarwishMohamed S.A. Darwish
Mohamed S.A. Darwish
Dual-functional iron oxide nanoparticles (IONPs), displaying self-heating and antibacterial effects are highly desired for biomedical application. This study involved the synthesis of functionalized IONPs coated with 3-aminopropyltriethoxysilane and polyethylene glycol via ultrasonic-assisted co-precipitation technique. The synthesized IONPs were then characterized by using Fourier-transform infrared spectroscopy, X-ray diffraction, dynamic light scattering, scanning electron microscopy, zeta potential, vibrating sample magnetometer and thermogravimetric analysis techniques. In addition, the effect of the synthesized IONPs on bacterial growth (S. aureus and E. coli) was studied. The influence of magnetic field power, as well as the viscous carriers on the heating efficiency of the synthesized IONPs was investigated. The specific absorption rate values increased as the power increased and decreased with the increase in the carrier viscosity. These characteristics render the synthesized iron oxide nanoparticles synthesized in the present study suitable for biomedical application as hyperthermic agents.

1 January 2015 in Journal of Nanomaterials
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Mohamed S.A. DarwishMohamed S.A. Darwish
Mohamed S.A. Darwish
NNNhung H. A. Nguyen
Nhung H. A. Nguyen
AŠAlena Ševců
Alena Ševců
ISIvan Stibor
Ivan Stibor
Magnetite (Fe3O4) nanoparticles were prepared using coprecipitation and subsequently surface‐functionalized with 3‐aminopropyltriethoxysilane (APTS), polyethylene glycol (PEG), and tetraethoxysilane (TEOS). Nanoparticle morphology was characterized using scanning electron microscopy, while structure and stability were assessed through infrared spectroscopy and zeta potential, respectively. Average size of the nanoparticles analysed by dynamic light scattering was 89 nm, 123 nm, 109 nm, and 130 nm for unmodified magnetite and APTS‐, PEG‐, and TEOS‐modified magnetite nanoparticles, respectively. Biological effect was studied on two bacterial strains: Gram‐negativeEscherichia coliCCM 3954 and Gram‐positiveStaphylococcus aureusCCM 3953. Most of modified magnetite nanoparticles had a significant effect onS. aureusand not onE. coli, whereas PEG‐magnetite nanoparticles displayed no significant effect on the growth rate of either bacteria.

21 May 2020 in Nanomaterials
Verified
Journal Article
Open access
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Mohamed S.A. DarwishMohamed S.A. Darwish
Mohamed S.A. Darwish
HKHoHyeon Kim
HoHyeon Kim
HLHwangjae Lee
Hwangjae Lee
CRChiseon Ryu
Chiseon Ryu
JLJae Young Lee
Jae Young Lee
JYJungwon Yoon
Jungwon Yoon
Magnetic ferrite nanoparticles (MFNs) with high heating efficiency are highly desirable for hyperthermia applications. As conventional MFNs usually show low heating efficiency with a lower specific loss power (SLP), extensive efforts to enhance the SLP of MFNs have been made by varying the particle compositions, sizes, and structures. In this study, we attempted to increase the SLP values by creating core-shell structures of MFNs. Accordingly, first we synthesized three different types of core ferrite nanoparticle of magnetite (mag), cobalt ferrite (cf) and zinc cobalt ferrite (zcf). Secondly, we synthesized eight bi-magnetic core-shell structured MFNs; Fe3O4@CoFe2O4 (mag@cf1, mag@cf2), CoFe2O4@Fe3O4 (cf@mag1, cf@mag2), Fe3O4@ZnCoFe2O4 (mag@zcf1, mag@zcf2), and ZnCoFe2O4@Fe3O4 (zcf@mag1, zcf@mag2), using a modified controlled co-precipitation process. SLP values of the prepared core-shell MFNs were investigated with respect to their compositions and core/shell dimensions while varying the applied magnetic field strength. Hyperthermia properties of the prepared core-shell MFNs were further compared to commercial magnetic nanoparticles under the safe limits of magnetic field parameters (<5 × 109 A/(m·s)). As a result, the highest SLP value (379.2 W/gmetal) was obtained for mag@zcf1, with a magnetic field strength of 50 kA/m and frequency of 97 kHz. On the other hand, the lowest SLP value (1.7 W/gmetal) was obtained for cf@mag1, with a magnetic field strength of 40 kA/m and frequency of 97 kHz. We also found that magnetic properties and thickness of the shell play critical roles in heating efficiency and hyperthermia performance. In conclusion, we successfully enhanced the SLP of MFNs by engineering their compositions and dimensions.