Browsing by Author "Mokwebo, Kefilwe Vanessa"

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    Advancement in electrochemical sensing of chloramphenicol in varying matrixes: a review
    (Elsevier B.V., 2025) Mulaudji, Kgwadu Percy; Mokwebo, Kefilwe Vanessa; De Bruin, Franklin Quelain; Pokpas, Keagan; Ross, Natasha
    Chloramphenicol (CAP) have demonstrated its broad effectiveness against bacterial infections. However, its persistence in the environment and potential toxicity led to strict global regulations limiting its use. As a result, rapid and accurate detection methods for CAP are being developed to protect public health and maintain regulatory compliance regarding its presence in the environment. Conventional analytical methods such as High-Performance Liquid Chromatography, Gas Chromatography, and Liquid Chromatography–Mass Spectrometry were commonly used for CAP detection. However, these conventional methods suffer challenges such as time-consumption, fabrication complexity, reproducibility, and cost. With electrochemical sensing techniques presenting varying valuable benefits, such as instant detection, low power consumption, simultaneous analysis, and portability, making them essential for timely monitoring of various analytes. The performance of electrochemical sensor is further boosted by integrating materials such as spinels, metal oxides, and metallic nanoparticles. These materials are broadly investigated as electrode interface components thanks to their features that collectively boost electrochemical sensor such as providing excellent electrical conductivity, distinct catalytic behavior, and larger surface areas. Furthermore, this paper reviews the impact of traditional and standards analytical methods, as well as their recent advancement based on the detection of CAP in aqueous media.
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    Trimetallic chalcogenide-sensitised interferon gamma aptasensor for tuberculosis
    (Elsevier Ltd, 2025) Uhuo, Onyinyechi Vivian; Januarie, Kaylin Cleo; Mokwebo, Kefilwe Vanessa
    Novel copper indium tin sulfide nanomaterial synthesized with chitosan capping agent.•IFN-γ TB biomarker aptasensor was fabricated using a χt-c-CITS sensing platform.•By aptamer surface density study, χt-c-CITS enhanced aptamer loading by 84.6 %.•χt-c-CITS increased aptasensor signal by 73.9 % and target detection by 85.7 %.•"Turn-on" assay format was achieved and monitored by capacitive charge measurements. Tuberculosis (TB) is a highly contagious disease whose eradication has become challenging due to the difficulty of early and real-time diagnosis, especially in developing countries. These challenges arise due to the time-consuming, expensive, complicated, and non-user-friendly nature of the current diagnostic techniques, making them difficult to use except by a highly trained medical laboratory specialist. Since biosensors offer a faster, simpler, and highly sensitive alternative to traditional methods, there is a growing interest in enhancing biosensor signals for efficient application. One such method of biosensor signal amplification is the use of nanostructured materials. In this work, we report the positive effect of tuning the properties of a substituted-kesterite nanomaterial, copper indium tin sulfide (CITS), using a chitosan capping agent, for efficient signal amplification of interferon gamma (IFN-γ) TB biomarker detection. This nanostructured chitosan-capped copper indium tin sulfide (χt-c-CITS) nanomaterials served as an excellent sensing platform, improving aptamer loading by 84.6 % and signal response by 73.9 %. High sensitivity to changes in IFN-γ concentration was obtained with the χt-c-CITS-based aptasensor between 100 fM to 1 pM dynamic linear range, and a detection limit of 23.2 fM. Excellent electrochemical stability was achieved with 94 % and 95.6 % signal stability recorded after 20 repeated chronocoulometry measurements and a 32-day storage period, respectively. The aptasensor likewise showed excellent specificity and selectivity to IFN-γ in the presence of interfering agents, with potential application in real biological samples.