Morphological and macrostructural studies of dog cranial bone demineralized with different acids

Gehan T. El-Bassyouni,Osiris W. Guirguis,Wafa I. Abdel-Fattah 한국물리학회 2013 Current Applied Physics Vol.13 No.5

Strong and weak acids were chosen for the bone decalcification process. Demineralization of dog cranial bone was carried out using 0.6 M concentration of either of hydrochloric, lactic or citric acid. Consequent morphologic changes were correlated with the developed chemistry, porosity and structure through XRD and FT-IR of the matrices. The dielectric permittivity, loss angle, relaxation dielectric loss as well as a.c. electrical conductivity as functions of frequency and temperature were measured. Zeta potential was evaluated at physiologic pH and temperature and correlated with the developed structures. The results prove lower dielectric properties of demineralized matrices compared to control and exhibited high dissipation of electric energy with more than one relaxation mechanism. This variation proves that the spectral behavior depended on the nature of the bone matrix which resulted from the phase compositions of bone and its crystallite size. The behavior of the obtained results is attributed to the differences of the demineralizing acids and their consequent actions on the matrices, i.e., the differences in the materials.

Ultraviolet-ozone irradiation of HPMC thin films: Structural and thermal properties

Abdel-Zaher, Nabawia A.,Moselhey, Manal T.H.,Guirguis, Osiris W. Techno-Press 2017 Advances in materials research Vol.6 No.1

The aim of the work was to evaluate the effect of ultraviolet-ozone ($UV-O_3$) irradiation with different times on the structure and thermal properties of hydroxypropyl methylcellulose (HPMC) in the form of a thin film to be used as bioequivalent materials according to their important broad practical and medical applications. HPMC thin films were exposed to $UV-O_3$ radiation in air at a wavelength of 184.9 nm.The beneficial effects of this treatment on the crystallinity and amorphousity regions were followed by X-ray diffraction technique and FTIR spectroscopy. Differential scanning calorimetry, thermogravimetric and differntial thermal analyses were used in order to study the thermal properties of HPMC samples following the process of photodegradation. The obtained results indicated that the rate of degradation process was increased with increasing the exposure time. Variations in shape and area of the thermal peaks were observed which may be attributed to the different degrees of crystallinity after exposing the treated HPMC samples. This meant a change in the amorphousity of the treated samples, the oxidation of its chemical linkages on its surface and its bulk, and the formation of free radical species as well as bond formation.

Saudi Cotton Fabrics Treated with Chitosan and Different Concentrations of ZnO Nanoparticles: Preparation, Characterization, and Demonstration

Najlaa D. Alharbi,Hanan H. Amer,Nabawia A. El‑Zaher,Osiris W. Guirguis 한국섬유공학회 2023 Fibers and polymers Vol.24 No.2

In this paper, treated Saudi cotton fabrics were prepared by dipping them in chitosan and chitosan/ZnO-NPs solutions offour different concentrations (10, 20, 30, and 40 wt% ZnO-NPs). The chemical compositions, optical properties, mechanicalcharacteristics, and air permeability of the prepared fabrics after immersion were investigated. The tristimulus valuesof the CIE, color parameters, extinction coefficient, and color strength were evaluated using reflectance spectra recorded inthe visible region. Untreated fabric and treated cotton fabrics (CF/Ch/ZnO-NPs) were assessed with regard to washability,acidic perspiration, and alkaline perspiration. Differences in the ratio of distinct bands can be seen in the FTIR spectroscopydata, indicating that the intensity of the O–H band is decreasing. Differences in the ratio of the distinct bands can be seen inthe FTIR spectroscopy data, indicating that the O–H band’s intensity is decreasing. The photon energy dependence of theabsorption coefficient revealed that optical transmission is allowed and direct. The ultraviolet protection factor (UPF) wasdetermined using color strength analysis, and the results showed that the treated cotton fabrics provide good-to-very goodUV protection. The fabrics were also very durable when it came to multiple washes. The mechanical characteristics and airpermeability data show a relationship between the presence of chitosan and the quantities of ZnO-NPs, as well as interactionsbetween them and the fabric network. This is the first study to try and improve the characteristics of Saudi cotton fabrics, sothat they can be used in a variety of industrial and medicinal applications.

Enhancing the Stability, Hydrophilicity, Mechanical and Biological Properties of Electrospun Polycaprolactone in Formic Acid/Acetic Acid Solvent System

Basma Ekram,Bothaina M. Abd El-Hady,Abeer M. El-Kady,Sherif M. Amr,Hala Gabr,Ahmed I. Waly,Osiris W. Guirguis 한국섬유공학회 2019 Fibers and polymers Vol.20 No.4

Electrospun polycaprolactone is widely used in the medical field. Formic acid/acetic acid (FA/AA) solvent systemis one of the safest solvents used for the production of nano-range polycaprolactone (PCL) fibers, although it has a very lowstability. In the present study, the stability of PCL in FA/AA system was enhanced by sodium hydrogen carbonate (NaHCO3)addition with three different concentrations (1, 5 and 10 wt%). The resultant electrospun fiber properties were compared tothat treated by alkaline hydrolysis. The viscosity and conductivity of PCL solutions were measured before the electrospinningprocess. Moreover, the obtained electrospun PCL mats were characterized by SEM, FT-IR, XRD, contact anglemeasurements, degradability, swelling, and mechanical properties, as well as their ability to enhance the proliferation andadhesion of mesenchymal stem cells (MSCs). It was found that NaHCO3 not only enhanced the fiber properties, such ashydrophilicity, degradability and mechanical properties but also had a significant effect on the stability of polycaprolactone inFA/AA solvent system, as well as an enhanced MSCs proliferation and adhesion. Although hydrolyzed PCL showed high cellviability and adhesion, it showed much lower mechanical properties (0.7 MPa) compared to neat PCL (1.3 MPa) and PCLNaHCO3(5.1 MPa). In conclusion, the addition of NaHCO3 to PCL solution prior to the electrospinning process represents anovel and an effective approach to improve the physicochemical properties and biological behavior of electrospun PCL matsfor tissue engineering application.

Experimental Study on Antimicrobial Activity of Silk Fabric Treated with Natural Dye Extract from Neem (Azadirachta indica) Leaves

Abeer A. Abd El Aty,Gehan T. El-Bassyouni,Nabawia A. Abdel-Zaher,Osiris W. Guirguis 한국섬유공학회 2018 Fibers and polymers Vol.19 No.9

In the present study, a novel eco-friendly production of silk fabrics dyed with different natural dye bath concentrations (40, 80, 120, 160, 200 and 240 g/l) extracted from neem (Azadirachta indica) leaves was developed. The surface morphology of the fabrics was examined by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy to characterize the chemical structure of the fabrics. The SEM images of the undyed fabric show that the fabric was tightly woven with little porosity between the fibres with dozens of silk threads in orthogonal directions. By increasing the neem concentration, a scale of fine particles grew on the surface of the silk fabrics with little macroscopical defects was demonstrated. The fiber diameters and tightness between filaments were significantly increased. The FTIR displayed that, neem dye does not change the characteristic peaks of the silk fabrics. Also, the evaluation of the antimicrobial activity of the undyed and neem dyed silk fabrics was monitored for Gram positive and Gram negative bacteria in addition to yeasts and fungi by using the agar diffusion method. The comparison between the different dye bath concentrations was based on the inhibition zones obtained after incubation. The antimicrobial activity in leaf extract of neem was estimated in Staphylococcus aureus, Bacillus subtilis and Lactobacillus cereus (Gram positive bacteria); Escherichia coli (Gram negative bacteria); Candida albicans and Candida tropicalis (yeasts); and Aspergillus niger and Fusarium solani (fungi). The results emphasized that, the highest neem dye bath concentration (240 g/l) was found to display good inhibitory effect against the Gram positive and reasonable activity against the Gram negative bacteria. Furthermore, the different dye bath concentrations possess no activities against yeast and fungi. In conclusion, the data reveal that the increase of neem dye concentration does not damage the silk fabric; however, it improves its antimicrobial activity by incorporating with antimicrobial agent. The current study highlighted that using neem leaves had beneficial effect in controlling the pathogenic microbial organisms.

Characterizations of nano-zinc doped hydroxyapatite to use as bone tissue engineering

Abdel-Ghany, Basma E.,Abdel-Hady, Bothaina M.,El-Kady, Abeer M.,Beheiry, Hanan H.,Guirguis, Osiris W. Techno-Press 2015 Advances in materials research Vol.4 No.4

Contamination by bacterial strands is a major problem after bone replacement surgeries, so there is a great need to develop low cost biocompatible antibacterial bioactive scaffolds to be used in bone tissue engineering. For this purpose, nano-zinc doped hydroxyapatite with different zinc-concentrations (5, 10 and 15 mol%) was successfully prepared by the wet chemical precipitation method. The prepared powders were used to form porous scaffolds containing biodegradable Ca-cross-linked alginate (5%) in order to enhance the properties of alginate scaffolds. The scaffolds were prepared using the freeze-gelation method. The prepared powders were tested by X-ray diffraction; transmission electron microscope and Fourier transform infrared analyses, while the prepared scaffolds were investigated by Fourier transform infrared analyses, thermogravimetric analyses and measurement of the antibacterial properties. Best results were obtained from scaffold containing 15% mol zinc-doped hydroxyapatite powders and 5% alginate concentration with ratio of 70:30.