Department of Biomedical Engineering
Permanent URI for this collection
Browse
Recent Submissions
Item Investigating the Influence of Temperature on Kaolinite- Base Synthesis of Zeolite and Urease Immobilization For Potential Fabrication of Electrochemical Urea Biosensor(University of Ghana, 2018-05) Anderson, D.E.Temperature-dependent zeolite synthesis revealed unique surface morphology, surface area and pore size that influence morphology of zeolite synthesised from kaolin in the immobilization of urease on gold electrode support for biosensor fabrication. XRD characterization identified Zeolite X (Na) at all crystallization temperatures tested. However, Nitrogen adsorption and desorption results showed pore size and pore volume of Zeolite X (Na) 60 °C, Zeolite X (Na) 70 °C and Zeolite X (Na) 90 °C range from 1.92 nm – 2.45 nm and 0.012 cm3/g – 0.061 cm3/g respectively, with no significant differences. The specific surface area of Zeolite X (Na) at 60, 70 and 90 °C was 64 m2/g, 67 m2/g, and 113 m2/g respectively. The pore size, specific surface area and pore volumes of Zeolite X (Na) 80 °C and Zeolite X (Na) 100 °C were dramatically increased to 4.21 nm, 295 m2/g, 0.762 cm3/g and 4.92 nm, 389 m2/g, 0.837 cm3/g in that order. The analytical performance of the embedded urease in Zeolite X (Na) was also investigated using cyclic voltammetry measurements and the results showed distinct cathodic and anodic peaks by Zeolite X (Na) 80 °C and Zeolite X (Na) 100 °C. The molar conductance of the modified zeolite biosensors was measured as a function of urea concentration and gave an average exponential decay regression fit of 0.98. The findings in this study suggest crystallization temperature is a critical parameter for electrochemical analysis of zeolites synthesized from natural sources for various biomedical applications.Item Isolation And Characterization Of Cassava Fibre For Tissue Engineering Scaffold Application(University of Ghana, 2017-07) Diabor, E.Cassava bagasse and its extracted cellulose fibres have seen frequent application mostly in the packaging industry as reinforcement material in plastic composites development. However, the material properties such as the mechanical properties of the single elementary cassava cellulose fibres have not been examined and reviewed literature does not show its potential use in the development of tissue engineering scaffolds for cell culture. The study, therefore, characterized the mechanical properties, physicochemical, morphological and microstructural characteristics and thermal degradation profiles of single elementary cellulose fibre as well as the central vascular fibre (“thick-core fibre) isolated from three genotypes of cassava (tagged in this study as ID4, ID6 and AF). Additionally, the study examined the effect of incorporating cassava cellulose microfibres as reinforcement on the mechanical properties and microstructure characteristics of three-dimensional gelatin scaffolds. Non-treated isolated cassava fibres were tested according to ASTM C1557. Three-dimensional cassava microfibre/gelatin scaffolds with different fibre weight fractions were fabricated using phase separation and freeze-drying methods. Tensile test results showed that there was no significant difference (p > 0.05) in mechanical properties recorded between the single elementary fibre and vascular fibre (thick-core) for the three cassava genotypes. Different genotypes of cassava fibre showed significant differences (p < 0.05) in tensile strength and Young’s modulus, with ID4 fibre recording the highest average tensile strength of 7.567 ± 3.844 MPa and highest elastic modulus of 336.485 ±130.803 MPa. XRD analysis showed similar diffraction pattern with minimal variation in signal intensities for both single and thick-core fibres for all cassava genotypes suggesting nonsignificant differences in crystalline structure between them. TGA analysis showed that cassava fibre is thermally stable between the temperatures of 100 °C – 200 °C. The cassava cellulose microfibre/gelatin scaffolds fabricated showed rough surfaces compared to pure gelatin scaffolds and were highly porous with surface porosity ranging between 84 and 90%, and had interconnected pores of average size 36 ±12 μm. Gelatin scaffolds containing up to 7% cassava cellulose microfibre load recorded a maximum compressive strength of 0.29±0.02 MPa, about eight (8) times higher than that for the pure gelatin scaffolds and average Young’s modulus of 1.31 ±0.03 MPa, about four times higher than pure gelatin scaffolds. Preliminary theoretical modelling using Halpin-Tsai model could accurately explain the variabilities in the compression modulus of the gelatin composite scaffolds. In all, the results showed that cassava fibre has considerable mechanical strength and stiffness and can be used as reinforcement filler to improve the mechanical integrity of tissue engineering polymer scaffolds. The cassava fibre/gelatin scaffolds showed surface architecture that could improve cell–matrix adhesion and efficient cell seeding and diffusion of nutrients during cell culture.Item Computer–Aided Approaches To Discovery Of Novel Drugs Against The Human Hookworm Necator Americanus (Nematoda: Ancylostomatidae)(University of Ghana, 2017-07) Agyapong, O.There is a crucial need to develop novel anthelminthic drugs due to the mounting disease burden and increasing evidence of hookworm resistance to drugs such as albendazole and mebendazole, which for decades have been used to treat the infection. Consequently, it is exigent to develop alternative drugs with improved therapeutic efficacy. Natural products due to their unique active ingredients have been shown to possess exceptional structures with chemical diversity that is unmatched by any synthetic libraries. It is imperative to leverage natural products to augment hookworm drug discovery. Therefore, this study aimed to: (i) identify potential novel anthelminthic lead compounds by screening African natural product-derived ligands against beta tubulin of Necator americanus, a known hookworm receptor and (ii) develop support vector machine-based proteochemometric modelling (PCM) for bioactivity profiling of beta tubulins receptors. The 3D structure of the beta tubulin of hookworm with UniProt entry W2T758, was generated using homology modelling. The model was subjected to molecular dynamics simulations and active site interactions prediction. The first set of ligand libraries comprising 885 natural product compounds obtained from African medicinal plants database (AfroDb) combined with Dichapetalin A, were screened against the receptor. ZINC14760755 and ZINC28462577 compounds were found to be potential leads due to promising binding affinity, active site interactions and pharmacokinetic profiles. Additionally, a second set comprising 2297 compounds derived from Northern African Natural Product Database (NANPDB) were virtually screened. The compound S,5Z,8Z,11Z,13E,17Z-15-hydroxy-1-(2,4,6-trihydroxyphenyl)-15-methylicosa-5,8,11,13,17-pentaen-1-one exhibited plausible binding affinity, toxicity and pharmacokinetic profile. The aforementioned natural compounds are potential leads which can be experimentally characterised for possible pre-clinical trials. Support vector machine based proteochemometric modelling was also developed to predict the bioactivity relations between beta tubulin variants and small compounds using an interaction dataset retrieved from BindingDB. The model achieved reasonably good performance with a ROC-AUC of 87%, an MCC of 0.75 and a classification error of approximately 4%, although it was trained on a small dataset. The model allows the prediction of the likelihood of interactions between query datasets comprising ligands in SMILES format and protein sequences of beta tubulin targets. In future, larger bioactive datasets of beta tubulins originating from high throughput experiments can be utilised to possibly enhance the performance of the hookworm PCM model.