@article{el-naggar_wael_hemdan_abdelgawad_elsabee_el-zayat_abdel hady_hashem_2024, title={Chitosan microflower-embedded gelatin sponges for advanced wound management and hemostatic applications}, volume={276}, ISSN={["1879-0003"]}, DOI={10.1016/j.ijbiomac.2024.133749}, abstractNote={The study explored the antimicrobial and antibiofilm properties of chitosan microflowers (CMF) in sponges. The main objective was to enhance the manufacture of CMF by employing varying quantities of calcium chloride (CaCl2) and tripolyphosphate (TPP). CMF was then combined with gelatin (GE) in different proportions to produce three sponge samples: CMF0@GE, CMF1@GE, and CMF2@GE. The CMF had a morphology like that of a flower and produced surfaces with a porous sponge-like structure. The antibacterial activity, as determined by the zone of inhibition (ZOI), increased with greater doses of CMF. Among the tested samples, CMF2@GE had the greatest activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecium. CMF2@GE successfully suppressed biofilm formation, decreased clotting time to an average of 212.67 s, and exhibited excellent biocompatibility by preserving over 90 % viability of human skin fibroblast cells at dosages below 100 μg/mL. The results indicate that gelatin sponges filled with CMF have considerable promise as flexible medical instruments for wound healing and infection control.}, journal={INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES}, author={El-Naggar, Mehrez E. and Wael, K. and Hemdan, Bahaa A. and Abdelgawad, Abdelrahman M. and Elsabee, M. Z. and El-Zayat, Emad M. and Abdel Hady, Mayssa and Hashem, M. M.}, year={2024}, month={Sep} }
 @article{el-sawaf_abdelgawad_nassar_elsherbiny_2024, title={Immobilization of biosynthesized gallium nanoparticles in Polyvinylpyrrolidone/Sodium alginate films: Potent bactericidal protection against food spoilage bacteria}, volume={274}, ISSN={["1879-0003"]}, DOI={10.1016/j.ijbiomac.2024.133438}, abstractNote={The increasing threat of spoilage bacterial infections, driven by the resistance of bacteria to many antimicrobial treatments, is a significant worldwide public health problem, especially concerning food preservation. To tackle these difficulties, this research investigates the possibility of using packaging sheets that include antimicrobial agents and increasing the prolonged storage time by preventing the bioburden of foodborne pathogens. This approach uses metal nanoparticles' ability to prevent harmful bacteria that cause food spoiling. Gallium nanoparticles (GaNPs) were created using a water-based extract from Andrographis paniculata leaves as a bioreducing agent. The GaNPs were added to a film made of sodium alginate (SA) and polyvinylpyrrolidone (PVP). The study showed that incorporating GaNPs into polymer films resulted in films with a desirable contact angle and decreased water vapor permeability. Significantly, the developed films demonstrated increased efficiency against E.coli O157 compared to other species. Also, it exhibited increased vulnerability to bacterial strains at the biofilm stage, surpassing PVP-SA/GaNPs-0. Remarkably, the toxicity tests showed that the films exhibited no cytotoxicity. Overall, the films indicated their potential for avoiding bacterial bioburden, prolonging the shelf life of perishable products, and contributing to diverse antimicrobial applications in the food industry.}, journal={INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES}, author={El-Sawaf, Ayman K. and Abdelgawad, Abdelrahman M. and Nassar, Amal A. and Elsherbiny, Dalia A.}, year={2024}, month={Aug} }
 @article{elsherbiny_abdelgawad_hemdan_montaser_el-sayed_jockenhoevel_ghazanfari_2023, title={Self-crosslinked polyvinyl alcohol/cellulose nanofibril cryogels loaded with synthesized aminophosphonates as antimicrobial wound dressings}, ISSN={["2050-7518"]}, DOI={10.1039/d3tb00926b}, abstractNote={Self-crosslinked porous cryogels derived from polyvinyl alcohol (partially and fully hydrolyzed) and cellulose nanofibril blends were formulated and used as drug vehicles for newly synthesized α-aminophosphonate drugs.}, journal={JOURNAL OF MATERIALS CHEMISTRY B}, author={Elsherbiny, Dalia A. and Abdelgawad, Abdelrahman M. and Hemdan, Bahaa A. and Montaser, Ahmed S. and El-Sayed, Ibrahim El-Tantawy and Jockenhoevel, Stefan and Ghazanfari, Samaneh}, year={2023}, month={Jun} }
 @article{jacobs_abdelgawad_jockenhoevel_ito_ghazanfari_2023, title={Warp-knitted fabric structures for a novel biomimetic artificial intervertebral disc for the cervical spine}, ISSN={["1573-4803"]}, DOI={10.1007/s10853-023-08544-x}, abstractNote={AbstractAs an attempt to better replicate the complex kinematics of a natural disc, a novel biomimetic artificial intervertebral disc replacement (bioAID) has been developed containing a swelling hydrogel core as nucleus pulposus, a fiber jacket as annulus fibrosus and metal endplates to connect the device to the adjacent vertebrae. The first prototype consisted of a weft-knitted fiber jacket, in which only a single fiber was used to create the jacket structure. This can endanger the structural integrity of the complete device upon yarn damage. Therefore, in this study, several warp-knitted textile structures were assessed to (1) ensure structural integrity, (2) while allowing for swelling constraint of the hydrogel and (3) behaving as one integrated unit similar to the natural IVD. Moreover, the fiber jacket should (4) act as a scaffold that allows bone ingrowth to ensure long-term stability and (5) have a good durability, (6) be wear resistant and (7) have good manufacturing feasibility with good quality control. In this study, 4 different stitch patterns, including 2 × 1 and 1 × 1 lapping with and without a pillar stitch, were produced. The effect of the stitch pattern and stitch density on the fabric mechanical properties and device swelling and compressive strength was assessed. As a next step, the effect of using multiple layers of fabrics, mimicking the layered structure of annulus fibrosus, on the functional capacity of the bioAID was characterized. All textile structures were capable of limiting the swelling of the hydrogel while withstanding its internal pressure and showing sufficient wear resistance. However, only the 2 × 1 and 2 × 1 with pillar stitch had a pore size range that was suitable for cell infiltration to facilitate osseointegration as well as having the highest strength of the complete device to ensure safety under compression loading. Incorporating different number of jacket layers of these two stitch patterns did not show any significant effect. When also taking the structural parameters into consideration, the 2 × 1 lapping design with 4 layers was able to constrain hydrogel swelling, provide a high compressive strength, could facilitate cell infiltration and had dimensions within the range of a natural intervertebral disc.}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Jacobs, Celien A. M. and Abdelgawad, Abdelrahman M. and Jockenhoevel, Stefan and Ito, Keita and Ghazanfari, Samaneh}, year={2023}, month={May} }
 @article{elsherbiny_abdelgawad_el-naggar_hemdan_ghazanfari_jockenhoevel_rojas_2022, title={Bioactive tri-component nanofibers from cellulose acetate/lignin// N-vanillidene-phenylthiazole copper-(II) complex for potential diaper dermatitis control}, volume={205}, ISSN={["1879-0003"]}, DOI={10.1016/j.ijbiomac.2022.02.192}, abstractNote={Current research targets innovative medical textiles of nanofibrous nature and antibacterial activity to prevent diaper dermatitis. The work is based on electrospun nanofibers from cellulose acetate (CA) and lignin (Lig) polymers. A series of new copper complexes were synthesized and loaded to the CA/Lig solution mix then subjected to electrospinning, giving rise to the tricomponent bioactive mats CA/Lig/Cu-complex. The surface morphology of electrospun nanofiber mats was smooth and homogenous as the concentration of lignin increased in the mixture. The incorporation of lignin improved the electrospinnability of the cellulose acetate; however, it increased the fiber diameter. The water contact angle, absorption underload were significantly improved as lignin content increased. The incorporation of Cu-complex in electrospun CA and CA/Lig fiber mats occurred without any substantial change in the surface morphology, indicating well encapsulation of the complex. The electrospun mats were active against Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus epidermidis, and Streptococcus faecalis. The cytotoxicity, protein leakage, and biological results, together with the above studies, would advocate copper complex loaded CA/Lig nanofibers as a potential candidate for hygienic applications.}, journal={INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES}, author={Elsherbiny, Dalia A. and Abdelgawad, Abdelrahman M. and El-Naggar, Mehrez E. and Hemdan, Bahaa A. and Ghazanfari, Samaneh and Jockenhoevel, Stefan and Rojas, Orlando J.}, year={2022}, month={Apr}, pages={703–718} }
 @article{abdelgawad_hudson_2019, title={Chitosan nanoparticles: Polyphosphates cross-linking and protein delivery properties}, volume={136}, ISSN={["1879-0003"]}, DOI={10.1016/j.ijbiomac.2019.06.062}, abstractNote={Nanoparticles from chitosan, in general, can be prepared through ionotropic gelation, physical crosslinking, with anionic polyphosphates. Tripolyphosphate (TPP) is widely used for such purpose especially in drug delivery applications. TPP is a small ion with a triple negative charge throughout the physiologically acceptable pH range. However, the stability of size and surface charge of the particles still challenging. In the current work, the utilization of Hexametaphosphate (HMP) instead of Tripolyphosphate (TPP) as a cross-linking agent is being investigated. HMP is hexavalent molecule in the neutral and slightly basic medium which offers more binding sites readily available for interaction with chitosan. It is thought that increasing the availability of the binding sites in the HMP molecule would result in stronger ionic complexation with chitosan cationic charges. Consequently, such stronger binding improves particles' stability and lead to average size reduction. A comparative study between chitosan/TPP and chitosan/HMP nanoparticles under different complexation conditions was conducted to investigate the effect of HMP on nanoparticles formation. Bovine Serum Albumin (BSA) was applied as a protein model drug to explore the drug loading efficiency, 96.3%, is higher than its TPP, 91.87%, counterparts. However, TPP cross-linked particles showed superior stability upon storage.}, journal={INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES}, author={Abdelgawad, Abdelrahman M. and Hudson, Samuel M.}, year={2019}, month={Sep}, pages={133–142} }
 @article{el-naggar_abdelgawad_tripathi_rojas_2017, title={Curdlan cryogels reinforced with cellulose nanofibrils for controlled release}, volume={5}, ISSN={["2213-3437"]}, DOI={10.1016/j.jece.2017.10.056}, abstractNote={Curdlan based cryogels were prepared and tested for their structural and thermal properties by using field emission scanning electron microscopy and thermogravimetric analysis, respectively. Volume shrinkage, mechanical performance, swelling, solubility and density were accessed as a function of composition, which included cellulose nanofibrils (CNF) and polyethylene oxide (PEO). PEO/CURD and PEO/CURD/CNF cryogels exhibited porous and layered structures. The addition of CNF significantly improved the in-vitro release of a nonsteroidal anti-inflammatory drug (diclofenac sodium), which is a promising alternative to current non-biodegradable systems.}, number={6}, journal={JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING}, author={El-Naggar, Mehrez E. and Abdelgawad, Abdelrahman M. and Tripathi, Anurodh and Rojas, Orlando J.}, year={2017}, month={Dec}, pages={5754–5761} }
 @article{yan_abdelgawad_el-naggar_rojas_2016, title={Antibacterial activity of silver nanoparticles synthesized In-situ by solution spraying onto cellulose}, volume={147}, ISSN={["1879-1344"]}, DOI={10.1016/j.carbpol.2016.03.029}, abstractNote={Spray technique was used for the adsorption of in-situ silver nanoparticles (AgNPs) onto and inside the surface of nano- and micro- fibrillar cellulose (NFC and MFC) as well as filter paper. The abundance of hydroxyl and carboxyl groups located in NFC and MFC are used to stabilize Ag ions (Ag+) which were then in-situ reduced to (AgNPs) by chemical or UV reduction. The surface characteristic features, elemental analysis, particle size as well as size distribution of the obtained MFC, NFC and filter paper loaded with AgNPs were characterized via field emission scanning electron microscopy connected to energy dispersive X-ray spectroscopy (FESEM- EDX) and transmission electron microscopy (TEM). The associated chemical changes after growth of AgNPs onto the cellulose substrates were assessed by fourier transform infra-red (FT-IR) while the thermal stability of such systems were investigated by thermogravimetrical analyses (TGA). The antibacterial properties of AgNPs loaded NFC, MFC and filter paper as well was investigated against Escherichia Coli. The resulted data indicate that the particle size was found to be 11 and 26 nm for AgNPs nucleated on NFC and MFC—based papers respectively. The antibacterial activity of AgNPs loaded MFC exhibited higher antibacterial activity than that of AgNPs loaded NFC. Overall, the present research demonstrates facile and fast method for in-situ antibacterial AgNPs loading on cellulose substrates.}, journal={CARBOHYDRATE POLYMERS}, author={Yan, Jinhua and Abdelgawad, Abdelrahman M. and El-Naggar, Mehrez E. and Rojas, Orlando J.}, year={2016}, month={Aug}, pages={500–508} }
 @article{abdelgawad_el-naggar_eisa_rojas_2017, title={Clean and high-throughput production of silver nanoparticles mediated by soy protein via solid state synthesis}, volume={144}, ISSN={["1879-1786"]}, DOI={10.1016/j.jclepro.2016.12.122}, abstractNote={A one-pot method that uses solid-state reactions at ambient temperature is proposed for high throughput and green synthesis of silver nanoparticles. Nano-sized silver metal was synthesized in less than 5 min by simply eco-grinding silver nitrate, soy protein isolate powder and sodium hydroxide pellets, in the absence of any solvent or organic protector. The loading and reduction efficiency of the reaction was readily controlled by adjusting the soy protein isolate/silver nitrate molar ratio and sodium hydroxide loading. The formation of nanostructured silver was elucidated by using complementary spectroscopy and imaging techniques, including ultra-violet spectroscopy, Transmission and Field Emission Scanning Electron microscopy with Energy Dispersive X-ray, Dynamic Light Scattering, X-Ray Diffraction, Fourier Transform infra-red spectroscopy and Surface Chemical Composition. The reducing effect of soy protein isolate to convert silver ions into silver nanoparticles in high yields was demonstrated, with no evidence of aggregation or phase separation. The results indicate excellent prospects toward cleaner and scale-up synthesis of silver nanoparticles.}, journal={JOURNAL OF CLEANER PRODUCTION}, author={Abdelgawad, Abdelrahman M. and El-Naggar, Mehrez E. and Eisa, Wael H. and Rojas, Orlando J.}, year={2017}, month={Feb}, pages={501–510} }
 @article{el-naggar_abdelgawad_salas_rojas_2016, title={Curdlan in fibers as carriers of tetracycline hydrochloride: Controlled release and antibacterial activity}, volume={154}, ISSN={["1879-1344"]}, DOI={10.1016/j.carbpol.2016.08.042}, abstractNote={Curdlan (CURD) and polyethylene oxide were used to synthesize nanofibers as carriers of hydro soluble tetracycline hydrochloride (TCH). The viscosity, surface tension and conductivity of the precursor multicomponent aqueous solutions were determined and adjusted to produce defect-free fiber webs. Except for a slight increase in diameter, the addition of TCH did not affect the original morphology of the CURD/PEO nanofibers, as determined by FE-SEM imaging. However, the thermal stability of the system was enhanced (TGA and DSC). Moreover, water resistance, as measured with 24-h immersion tests, was observed upon crosslinking with glutaraldehyde. In-vitro activity measurements indicated a sustained and controlled TCH time-release pattern and excellent antibacterial activity against E. coli, as assessed by UV–vis spectroscopy and viable cell counting, respectively. Overall, we propose nanofibers based on CURD as promising platforms for scaffolds for wound dressing and drug delivery.}, journal={CARBOHYDRATE POLYMERS}, author={El-Naggar, Mehrez E. and Abdelgawad, Abdelrahman M. and Salas, Carlos and Rojas, Orlando J.}, year={2016}, month={Dec}, pages={194–203} }
 @article{abdelgawad_el-naggar_hudson_rojas_2017, title={Fabrication and characterization of bactericidal thiol-chitosan and chitosan iodoacetamide nanofibres}, volume={94}, ISSN={["1879-0003"]}, DOI={10.1016/j.ijbiomac.2016.07.061}, abstractNote={Two chitosan derivatives, namely, thiol-chitosan (TCs) and chitosan iodoacetamide (CsIA) were newly synthesized by reacting Cs with thiglycolic acid (TGA) and iodoacetic acid (IA) respectively. After being crosslinked with glutraldehyde (GA), the two derivatives were submitted to FT-IR and H1 NMR analysis for identification and characterization of their chemical features. As TCs and CsIA are water soluble, their electrospun nanofibres mats from aqueous solutions could be crosslinked and achieved using polyvinyl alcohol/Chitosan blend (PVA/Cs) polymers. Morphological structures of the obtained nanofibres and their webs were studied via those of TCs and CsIA free systems. The data also indicate that the crosslinked PVA/Cs/CsIA is more thermally stable than the crosslinked PVA/Cs/TCs and crosslinked PVA/Cs respectively. It was proved that the electrospun fibers containing TCs or CsIA display a superior antibacterial activity against negative bacteria E. Coli with a minimum inhibitory concentration (MIC) of 400μg/ml. These effects are rather in confirmation with bacterial kinetics essays which were also carried out in current work. Of particular interest is that the antimicrobial properties of fibers containing small concentration of either TCs or CsIA are much superior than those obtained with neat Cs electrospun nanofibres used as reference. By and large the results advocate the fibers webs containing TCs or CsIA as excellent candidates for wound dressing applications.}, journal={INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES}, author={Abdelgawad, Abdelrahman M. and El-Naggar, Mehrez E. and Hudson, Samuel M. and Rojas, Orlando J.}, year={2017}, month={Jan}, pages={96–105} }
 @article{abdelgawad_hudson_rojas_2014, title={Antimicrobial wound dressing nanofiber mats from multicomponent (chitosan/silver-NPs/polyvinyl alcohol) systems}, volume={100}, ISSN={["1879-1344"]}, DOI={10.1016/j.carbpol.2012.12.043}, abstractNote={Novel hybrid nanomaterials have been developed for antimicrobial applications. Here we introduce a green route to produce antibacterial nanofiber mats loaded with silver nanoparticles (Ag-NPs, 25 nm diameter) enveloped in chitosan after reduction with glucose. The nanofiber mats were obtained from colloidal dispersions of chitosan-based Ag-NPs blended with polyvinyl alcohol. Nanofibers (150 nm average diameter and narrow size distribution) were obtained by electrospinning and cross-linked with glutaraldhyde. The effect of crosslinking on the release of silver was studied by atomic absorption spectroscopy. Antimicrobial activity was studied by the viable cell-counting; mats loaded with silver and control samples (chitosan/PVA) with different degrees of cross-linking were compared for their effectiveness in reducing or halting the growth of aerobic bacteria. The results showed superior properties and synergistic antibacterial effects by combining chitosan with Ag-NPs.}, journal={CARBOHYDRATE POLYMERS}, author={Abdelgawad, Abdelrahman M. and Hudson, Samuel M. and Rojas, Orlando J.}, year={2014}, month={Jan}, pages={166–178} }