Faculty Scholarly Publications
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- ItemProdigiosin-loaded electrospun nanofibers scaffold for localized treatment of triple negative breast cancer(Elsevier, 2020-09) Akpan, U. M.; Pellegrini, M.; Obayemi, J. D.; Ezenwafor, T.; Browl, D.; Ani, C. J.; Yiporo, D.; Salifu, A.; Dozie-Nwachukwu, S.; Odusanya, S.; Freeman, J.; Soboyejo, W. O.Hybrid composite nanofibers, with the potential to enhance cell adhesion while improving sustained drug release profiles, were fabricated by the blend electrospinning of poly(d,l-lactic-co-glycolic acid) (PLGA), gelatin, pluronic F127 and prodigiosin (PG). Scanning Electron Microscopy (SEM) images of the nanofibers revealed diameters of 1.031 ± 0.851 μm and 1.349 ± 1.264 μm, corresponding to PLGA/Ge-PG and PLGA/Ge-F127/Ge, respectively. The Young's moduli were also determined to be 1.446 ± 0.496 kPa and 1.290 ± 0.617 kPa, while the ultimate tensile strengths were 0.440 ± 0.117 kPa and 0.185 ± 0.480 kPa for PLGA/Ge-PG and PLGA/Ge-F127/Ge, respectively. In-vitro drug release profiles showed initial (burst) release for a period of 1 h to be 26.000 ± 0.004% and 16.000 ± 0.015% for PLGA/Ge and PLGA/Ge-F127 nanofibers, respectively. This was followed by 12 h of sustained release, and subsequent slow sustained release of PG from the composite nanofibers. The cumulative release of PG (for three days) was determined to be 82.0 ± 0.1% for PLGA/Ge and 49.7 ± 0.1% for PLGA/Ge-F127 nanofibers. The release exponents (n) show that both nanofibers exhibit diffusion-controlled release by non-Fickian (zeroth order) and quasi-Fickian diffusion in the initial and sustained release regimes, respectively. The suitability of the composite nanofibers for supporting cell proliferation and viability, as well as improving sustained release of the drug were explored. The in-vitro effects of cancer drug (PG) release were also studied on breast cancer cell lines (MCF-7 and MDA-MB-231 cells). The implications of the results are discussed for the potential applications of drug-nanofiber scaffolds as capsules for localized delivery of chemotherapeutic drugs for the treatment of triple negative breast cancer.
- ItemEffect of hands-on science activities on Ghanaian student learning, attitudes, and career interest: A preliminary control study(Global Journal of Transformative Education, 2020-12) Beem, HeatherA quasi-experimental study was carried out with 309 Form 3 students across 9 public Junior High Schools in the Greater Accra Region of Ghana. The effect of Practical Education Network (PEN)’s approach of training STEM teachers to employ hands-on activities using low-cost, locally-available resources was studied in terms of student learning outcomes, attitudes towards learning science, and interest in STEM majors/ careers. Over a 2.5-month period, the science teacher at each experimental school received a weekly training on a hands-on activity and lesson observation by the respective PEN Trainer. A survey on attitudes towards science and a previous edition of the national exam (BECE) were administered to all students before and after the intervention. The mean pre-post differences were compared between the experimental and control schools. The intervention caused an average of 10.9% increase in exam scores (difference-in-differences), but the results were mixed at the school-level. Unpaired t-tests and Hedge’s g tests were used to determine statistical significance between the two groups. Student engagement increased significantly (p = 3 x 10 -7 , g = 0.85), and student enjoyment of science increased 22% more, on average. The intervention disproportionately affected the females positively, enabling greater learning gains (14.5% vs. 5.3% for the males), greater increase in engagement, and a significant shift in interest towards STEM majors and careers, which their male counterparts did not experience. Results from this study should inform the design of future studies with longer duration and which account for factors such as school infrastructure quality.
- ItemEffect of particle size and sintering time on the mechanical properties of porous Ti–6Al–4V implant(Springer Nature, 2020-04) Azeez, Akeem A.; Danyuo, Yiporo; Obayemi, John. D.Titanium alloys have been extensively used in biomedical applications owing to its low density, excellent biocompatibility (i.e., biological and chemical inertness), and unique mechanical properties. However, there is a high disparity between Young’s moduli of the implant and the natural bone. This disparity causes stress shielding in the body. This paper presents the effect of particle size and sintering time of Ti–6Al–4V powder used in the formation of a porous implant, sintered at 980 °C. Morphological characteristics of the sintered samples were obtained with a scanning electron microscope. The effect of surface hydrophilicity of the samples was elucidated via surface wettability testing using contact angle measurement with bio-fluid. Mechanical characterization was also evaluated with nanoindentation and a universal testing machine. The relation between Young’s modulus and sintering time was presented. It was observed that the wettability decreases with sintering time and the Ti alloy powder with particle size < 150 µm had the Young’s modulus that is closer to the modulus of the bone; the optimum sintering time was 5 h.
- ItemLaser application of nanocomposite hydrogels on cancer cell viability(MRS Advances, 2020) Danyuo, Yiporo; Salifu, A. A.; Ani, C. J.; Dozie-Nwachukwu, S.; Ezenwafor, Theresa; Yirijor, J.Nanocomposite hydrogels of poly-n-isopropyl were prepared by incorporating gold and magnetite nanoparticles. The nanocomposite-based hydrogels formed were geometrical, ~7.3 mm in diameter and 5 mm thick (in the swollen state). Morphological analysis was characterized by a scanning electron microscope. Drug-loaded hydrogels were subjected to laser heating at 1 W, 1.5 W and 2 W for 20 min in each laser cycle. The metabolic activities of the cells were analysed. The photothermal conversion efficiency of the nanocomposite hydrogels was also evaluated for P(NIPA)-AuNP-PG and P(NIPA)-MNP-PG to be 36.93 and 32.57 %, respectively. The result was then discussed for potential applications whereby metalbased hydrogels can be employed in microfluidic devices for targeted cancer drug delivery.
- ItemRecycling of plastic waste materials: Mechanical properties and implications for road construction(MRS Advances, 2020) Panashe, Jennifer Alista; Danyuo, YiporoThis paper presents a recent study on recycling poly-ethylene-tetraphylate (PET), known as plastic waste material in Ghana, to wealth. Composites were produced by heating aggregates together with shredded PET plastic waste material, while bitumen was added to the plasticcoated aggregates. The composites produced were reinforced with 4.5 wt%, 9.0 wt%, 13.6 wt%, and 18.0 wt% PET. Mechanical properties of the fabricated composite samples were studied with a Universal testing machine for optimization. The work demonstrated that shredded PET plastic waste material acts as a strong binding agent for bitumen that can improve on the shelf life of the asphalt. From the results, 13.6 wt% concentration of PET was shown to experience the maximum compressive strength and flexural strength. Besides, water resistance was shown to increase with PET concentrations/weight fraction. From the data characterized 13.6 wt% of PET plastic gives the optimum plastic concentration that enhances the rheological properties of bitumen. The implications of the result are therefore discussed for the use of 13.6 wt% PET in road construction.