Papers by Abdul Wahab Jatoi
DOAJ (DOAJ: Directory of Open Access Journals), 2015
Nano research & applications, Nov 23, 2018
I n the present work, we report our research on cellulose nanofibers decorated with silver nanopa... more I n the present work, we report our research on cellulose nanofibers decorated with silver nanoparticles by novel methods. Cellulose acetate was used as a precursor for cellulose nanofibers. Cellulose acetate nanofibers were fabricated by electrospinning and then treated with 0.01 M NaOH solution for 30 hours to produce cellulose nanofibers. Synthesis of silver nanoparticles was carried out by three simple methods. AgNO 3 was used as precursor for synthesis of silver nanoparticles. Three methods were used for reduction of ionic silver (Ag +) into AgNPs were heat treatment, N, N-Dimethylformamide induced heat treatment and 3,4-Dihydroxyphenethylamine coating. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), Fourrier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Field emission scanning electron microscopy (FESEM). Sizes of the AgNPs were calculated using Debye-Scherrer method and from the TEM images. SEM and FESEM images depicted regular morphology of the nanofibers. Structural modifications of cellulose acetate into cellulose were confirmed by FTIR and XRD analysis. Formation of the metallic silver was confirmed from XRD and XPS data. XRD data revealed FCC crystalline structure of the AgNPs. TEM images show cellulose nanofibers covered with well dispersed AgNPs.
Composites Communications
RSC Advances, 2016
The development of biocompatible nanocomposites for biomedical applications such as drug release ... more The development of biocompatible nanocomposites for biomedical applications such as drug release has attracted increasing attention in recent years.
The Journal of The Textile Institute
Fibers and Polymers, 2016
We report our study on fabrication of soluble eggshell membrane (SESM) and silk fibroin (SF) nano... more We report our study on fabrication of soluble eggshell membrane (SESM) and silk fibroin (SF) nanofibers composite (SF/SESM) for facemasks by electrospinning. Biocompatibility of the SF and SESM, determined from hydrophilicity results, is exploited in SF/SESM nanocomposite for facemask application. The SF/SESM nanocomposites were prepared in different ratios of SF and SESM. The samples were characterized by scanning electron microscopy (SEM), FTIR and water droplet adsorption tests conducted via water contact angle (WCA) and water droplet diffusion. The results revealed that addition of SESM has insignificant effect on the electrospinnability of SF nanofibers in the studied ratios. The SEM results depicted regular morphology of the nanofibers except increase in nanofiber diameter with addition of SESM. The FTIR results confirmed respective peaks of SF and SESM in SF/SESM nanocomposite. WCA of the nanofibers decreased with addition of SESM such that for SF/SESM30, 30 % SESM, it reduced to 0 o from 101 o for pure SF nanofibers. The research results demonstrate SF/SESM30 nanocomposite as optimum ratio of SF and SESM for facemasks and other biomedical applications.
Polymer Bulletin, 2017
Herein, we fabricated bead-free isotactic poly(4-methyl-1-pentene) (PMP) nanofiber membranes and ... more Herein, we fabricated bead-free isotactic poly(4-methyl-1-pentene) (PMP) nanofiber membranes and characterized their thermo-mechanical properties. PMP nanofiber membranes were electrospun and heat-treated at 180 and 220°C, and thermally treated under load. The report investigates the effect of thermal treatments on the morphology, degree of crystallinity and mechanical properties, improving the mechanical properties of PMP nanofibers. Prepared nanofibers were investigated by SEM, DSC, XRD and mechanical properties. The mechanical properties demonstrate a tensile strength, an elongation (%) and a Young's modulus of the nanofiber membranes. The DSC and WAXD analysis shows an increase of degree of crystallinity with thermal treatment. Thermally treated nanofibers under load demonstrate 4.1 times higher tensile strength and 14.1 times higher Young's modulus than PMP fibrous membrane. Thermally treated nanofibers under load at 200°C did not retain their structure and fuse with neighboring fibers, because it almost reached the melting temperature of (230°C).
Materials Science and Engineering: C, 2019
Although silver based nanofibers possess excellent bactericidal and bacteriostatic characteristic... more Although silver based nanofibers possess excellent bactericidal and bacteriostatic characteristics. However, excess release/contact with silver may induce harmful side-effects including carcinoma, argyria, argyrosis and allergies. Similarly, silver depletion may limit prolonged antibacterial activities as well. Thus present research proposes electrospun CA/ZnO/AgNPs composite nanofibers for biologically safer and sustained antibacterial applications. The ZnO/AgNPs were synthesized using dopamine hydrochloride (Dopa) as reducing agent to immobilize AgNPs on ZnO nanoparticles. A simple solution-mixing procedure effectively generated AgNPs on ZnO nanoparticles. Strong adhesive characteristics of Dopa initiate adsorption of silver ions on ZnO nanoparticle surfaces and its metal ion reducing properties generate AgNPs. Additionally, the Dopa mediation generates strongly adhered AgNPs. The ZnO/AgNPs were used to fabricate CA/ZnO/AgNPs nanofibers. Characterization techniques, XRD, XPS, TEM, FTIR and SEM confirmed synthesis of nanocomposites. Crystallite sizes of ZnO and AgNPs calculated by Debye-Scherrer equation were 17.85 nm and 11.68 nm respectively. Antibacterial assays confirmed CA/ZnO/AgNP's effectiveness in growth inhibition of E. coli and S. aureus strains on agar plate and in liquid medium. The nanofiber composites demonstrated 100% bactericidal properties against both the test strains. Bacterial growth inhibition in LB medium for 108 h indicated suitability of CA/ZnO/AgNPs composite nanofibers in sustained antibacterial applications such as antibacterial wound dressings and other applications demanding sustained antimicrobial properties.
Materials Letters, 2019
Herein we present our research on a novel three phase antibacterial wound dressing prepared from ... more Herein we present our research on a novel three phase antibacterial wound dressing prepared from carbon nanotubes, silver nanoparticles (AgNPs) and polyvinyl alcohol nanofibers. The AgNPs were generated on carbon nanotubes surfaces to synthesize carbon nanotubes-AgNP nanoparticles which were added into the polyvinyl alcohol nanofibers prior to electrospinning to prepare PVA/carbon nanotubes-AgNP composite nanofibers. All characterizations confirmed the three phase nanofiber architecture. Owing to growth of AgNPs on carbon nanotubes surfaces and embedding into PVA nanofibers the wound dressings are proposed for sustained and safer wound healing applications. The antibacterial test results confirmed excellent bactericidal and prolonged bacterial growth inhibition properties of the nanocomposites which suggest their suitability as sustained antibacterial wound dressing biomaterial.
Fibers and Polymers, 2016
Herein we report successful synthesis of silk fibroin (SF) three dimensional scaffolds (SF 3D-sca... more Herein we report successful synthesis of silk fibroin (SF) three dimensional scaffolds (SF 3D-scaffold) from SF sponge and SF nanofibers. Both the nanofibers and sponge were prepared from Bombyx mori fibroin. The SF 3D-scaffold was prepared by electrospinning the fibroin nanofibers over the sponge. Surface morphology was determined by scanning electron microscopy (SEM), while nanofiber diameter and pore size were measured using imageJ software. Effect of spinning time on the pore size and cell adhesion was determined. Average diameter of the SF nanofibers was measured to be 320 nm and pore size was found to reduce with increasing spinning time, such that, for 1 h spinning time pore size was 231 µm and the same for 3.5 h was 4.1 µm. However, the number of pores increased with spinning time. The results confirmed adhesion of MC3T3-E1 cells on the SF sponge, SF nanofibers and SF three dimensional scaffolds. Higher cell adhesion was found on the three dimensional scaffold in comparison to the nanofibers and sponge, possibly due to highly porous structure with very small and numerous pores in the resultant composite; hence more cell adhesion sites. The cell adhesion result confirmed biocompatibility of the SF 3D-scaffold and hence its suitability for applications in tissue engineering.
Materials Research Express, 2020
Here in we present our research on electrospun polyacrylonitrile nanofiber films embedded with ti... more Here in we present our research on electrospun polyacrylonitrile nanofiber films embedded with titania/AgNP nanoparticles for sustained antibacterial applications. Although silver possesses excellent antimicrobial characteristics and have been extensively exploited in applications where protection from microbial species and bacterial colonization is needed. Recently, it was discovered that silver may be allergic to skin and may induce detrimental side-effects such as argyria and argyrosis. Excess utilization of silver may even cause carcinoma. In continuation of our research on preparation of biologically safe antibacterial materials producing longer timed protection, here we proposed electrospun polyacrylonitrile nanofiber mats containing titania/AgNP composite nanoparticles. The titania/AgNP nanoparticles were prepared using polydopamine hydrochloride (pdopa) as adhesive and reducing agent. The nanoparticles were then added into polyacrylonitrile polymer solution and electrospun t...
Materials Science and Engineering: C, 2019
Herein we present our research on generation of silver nanoparticles (AgNPs) on cellulose nanofib... more Herein we present our research on generation of silver nanoparticles (AgNPs) on cellulose nanofibers by thermal treatment and DMF as reducing agents. The cellulose (CE) nanofibers were prepared by deacetylation of electrospun cellulose acetate (CA) nanofibers which were subsequently silver coated using AgNO3 followed by thermal and DMF induced reduction processes. The samples were characterized with scanning electron microscopy (SEM), Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and antibacterial assays. Effect of these methods on mechanical properties, thermal stabilities (DTA analysis) and swelling of the CE nanofibers were also studied. Both the processes were effective and efficient in generation of AgNPs on CE nanofibers with higher contents and very good spatial distributions. The XRD, XPS and TEM results evidenced formation metallic AgNPs. TEM images depicted the CE nanofibers highly decorated with spherical AgNPs. The DMF induced process generated AgNPs with comparatively larger sizes. The antibacterial results confirmed excellent antibacterial performance of the CEAgNPs against S. aureus and E. coli. The CEAgNP nanofibers well decorated with AgNPs having good spatial distribution and excellent antibacterial performance suggests CEAgNPs as promising candidate for efficient antimicrobial activities.
The Journal of The Textile Institute
Composites Communications
Materials Science and Engineering: C
Ultrasonics Sonochemistry
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Papers by Abdul Wahab Jatoi