Department of Chemical and Earth Sciences

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http://hdl.handle.net/20.500.11837/159
The Department of Chemical and Earth Sciences collection provides access to the academic and research outputs of staff and students. This collection includes research publications, conference papers, and examination question papers. The Department encompasses a broad range of disciplines, including Geography and Environmental Studies, Applied Remote Sensing & Geographic Information Systems (GIS), Geology, and Pure and Applied Chemistry. By integrating theoretical knowledge with practical laboratory and field-based research, the Department equips students with analytical, technical, and problem-solving skills to address scientific, environmental, and societal challenges. Through the preservation and dissemination of these resources, the collection supports teaching, learning, and research, while fostering innovation, environmental stewardship, and sustainable development within the University and the wider community.

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Browsing Department of Chemical and Earth Sciences by Author "Aderibigbe, B.A."

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    Design and characterization of sodium alginate-based scaffolds for the treatment of burn wounds
    (University of Fort Hare, 2024) Ndlovu, Sindi Prescila; Aderibigbe, B.A.; Motaung, S.
    Burn injuries have a considerable impact on mortality and morbidity rates due to the systemic immune changes and increased infection risks that they cause. These factors hinder the healing process and allow microbial invasion, leading to prolonged hospital stays and increased mortality rates. In this study, sodium alginate-based membranes, topical gel, and nanofibers were prepared and evaluated as potential wound dressings that are affordable and effective for treating burn wounds, suggesting that they can also be accessible to low income individuals. The topical gels were prepared from sodium alginate (SA), Carbopol, Carboxymethyl cellulose (CMC), and polyethylene glycol (PEG). The gels were loaded with Capparis sepiaria extract to enhance their antibacterial efficacy. Membranes were designed from SA/Gum acacia/PVA/PF127 and loaded with Capparis sepiaria, and nanofibers were developed from SA/PVA/PLGA and loaded with Capparis sepiaria. The topical gels, membranes, and nanofibers were evaluated using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), and X-ray diffraction (XRD), which confirmed the successful preparation of these three classes of wound dressings. The Water Vapor Transmission Rate (WVTR) values of the membranes and nanofibers were in a range of 1654.73 ± 0.74 and 319.24 ± 9.82 g/m2.24h, respectively, which is suitable for application on burn wounds, preventing moisture accumulation and reducing the risk of infection. The viscosity of the topical gels was in the range of 12 ± 0-7720 ± 152.83 and 20 ± 9.78-5256 ± 61.10 cP at 50 and 100 rPM, respectively, revealing a thixotropic/pseudoplastic behaviour, indicating that they can be easily applied on the wound bed. The membranes were biodegradable, with good swelling behaviour, showing their capability to absorb excess wound exudate. The membrane’s mechanical properties were studied, and their tensile strength was suitable for dermal application without causing discomfort upon removal from the wound bed. The topical gels, membranes, and nanofibers scaffolds displayed superior antibacterial efficacy against some gram-positive and gram-negative bacteria strains compared to the employed commercial wound dressing in this study that are responsible for the chronicity of burn wounds, such as Pseudomonas aeruginosa, Enterococcus faecalis, Mycobacterium smegmatis, Escherichia coli, Enterobacter cloacae, Proteus vulgaris, and Staphylococcus aureus. These three wound dressings showed a non-toxic effect on the immortalized human keratinocyte cells (HaCaT) cells, with a % cell viability of more than 85%. Furthermore, the wound dressings' capability to promote blood clotting was significant. The non-toxic nature of the wound dressings supported significant cell adhesion, migration, and proliferation than the commercial wound dressing used in the study. The three classes of SA-based wound dressings (i.e., topical gels, membranes, and nanofibers) displayed superior biological properties than commercial wound dressing, revealing their potential application as wound dressings on burn wounds.
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    Development and in vitro biological evaluation of hybrid wound dressings as potential therapeutics for the treatment of infected wounds
    (University of Fort Hare, 2024) Kula, Hlalisa; Aderibigbe, B.A.; Motaung, S.
    Infected wounds are challenging to treat and are identified as the leading causes of global mortality and morbidity. Improper management can result in amputations if not properly treated with appropriate wound dressings. The mental health of wound patients is great and some of them suffer from post-traumatic stress disorder (PTSD) due to prolonged hospitalisation. The problem associated with the treatment of infected wounds is that most commercially available wound dressings fail to cater for the wounds by not protecting the wounds from microbial invasion, non-compatibility, and inability to accelerate the wound healing process. Biopolymers such as polyvinyl alcohol (PVA), Hydroxypropylmethylcellulose (HPMC), Carboxymethylcellulose (CMC), and Sodium alginate (SA) were explored for preparation of hydrocolloids (single and double-layer) and cryogels loaded with Capparis sepiaria extract (cs-PE). The wound dressings were characterized by FTIR, SEM, and XRD. The mechanical properties such as tensile strength, thickness, and folding endurance were also evaluated. The tensile strength of the hydrocolloids ranged between 0.346 ± 0.13 to 5.590 ± 0.52 MPa and cryogels were between 0.094 ± 0.03 – 12.261 ± 0.56 Mpa. The surface pH of the dressings was in the range of 4.0-6.8 and the Water Vapour Transmission Rate (WVTR) ranged from 1032 ±2.79 to 9480 ±0.002 g/m2 .day-1 . The prepared biopolymer-based wound dressings incorporated with Capparis sepiaria exhibited good antimicrobial activity. XRD showed the amorphous nature of the wound dressings and the absence of free drugs, revealing their inability to trigger skin irritation. The antibacterial activity, cytotoxicity and wound scratch healing assay results showed that the prepared hydrocolloids and cryogels are effective against selected species of bacteria that are common in infected wounds, non-toxic, induce haemostatic effect, and have excellent capability to promote skin cell migration and proliferation. These features make them potential wound dressings for treating infected wounds.
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    Synthesis and characterization of hybrid compounds containing ferrocene scaffold as potential anticancer drugs
    (University of Fort Hare, 2024-11) Ndlovu, Sijongesonke; Aderibigbe, B.A.
    Cancer is one of the diseases, and its treatment suffers from several limitations. For instance, there are several commercially available drugs to treat this lethal disease. However, they still display shortcomings such as drug toxicity and resistance, poor water solubility, poor bioavailability, and severe side effects. Thus, their efficacy is compromised by these limitations. The emerging drug repurposing strategy is gaining momentum from medicinal researchers. This comes after several compounds have been reported to possess various biological activities. Thus, the hybridization approach via drug reprofiling has been an interesting field of research. Hence, this study reports the synthesis of hybrid compounds as potential anticancer drugs. Two ferrocene scaffolds (ferrocene and ferrocene carboxaldehyde) were modified to keto-ferrocene butanoic acid (16) and methyl-ferrocenol (18) and hybridized with several selected pharmacophores via esterification and amidation reactions using suitable functional groups, resulting in a class of eleven esterlinked (19-29) and five amide-linked (30 34) hybrids. The characterization techniques including Fourier Transform Infrared (FTIR) spectroscopy, Nuclear magnetic resonance (NMR) spectroscopy, and Liquid chromatography mass spectrometry (LC-MS) confirmed the successful development of these hybrids by displaying the expected signals at the expected regions of the spectra. Most importantly, the molecular weights calculated corresponded with those obtained by the LCMS on the samples. In vitro, two hybrid compounds, 20 ( thymol-keto-ferrocene butanoate) and 27 (ursolic-ferrocenoate), were the most promising anticancer compounds, displaying a 50% cytotoxic effect against cervical cancer (HeLa) and Chinese hamster ovary (CHO) cell lines and less than 20% on normal cells (VERO). Noteworthy, the cytotoxicity was concentrationdependent. Furthermore, hybrid 20 was the most effective compound with a selective index greater than one from the series. Thus, the findings from the molecular docking of these two most promising hybrids further confirmed the in vitro findings, which revealed high negative docking scores, signifying binding interactions and good binding affinity of the compounds towards the biological targets. The in silico predictions of the two also showed they are non-toxic, have a good bioavailability score (0.55<), are P-gp substrates, and do not inhibit most of the CPY enzymes. Hence, this study reveals the efficacy of synthesizing hybrid compounds containing ferrocene scaffolds and plant-based pharmacophores, such as thymol and ursolic acid. Developing hybrid molecules is a promising synthetic approach for potent anticancer agents.