Browsing by Author "Sibuyi, Nicole"

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    Antibacterial activity and cytotoxicity screening of acyldepsipeptide-1 analogues conjugated to silver/indium/sulphide quantum dots
    (Multidisciplinary Digital Publishing Institute (MDPI), 2024) Cobongela, Sinazo; Makatini, Maya; Sibuyi, Nicole
    The continuous rise in bacterial infections and antibiotic resistance is the driving force behind the search for new antibacterial agents with novel modes of action. Antimicrobial peptides (AMPs) have recently gained attention as promising antibiotic agents with the potential to treat drug-resistant infections. Several AMPs have shown a lower propensity towards developing resistance compared to conventional antibiotics. However, these peptides, especially acyldepsipeptides (ADEPs) present with unfavorable pharmacokinetic properties, such as high toxicity and low bioavailability. Different ways to improve these peptides to be drug-like molecules have been explored, and these include using biocompatible nano-carriers. ADEP1 analogues (SC005-8) conjugated to gelatin-capped Silver/Indium/Sulfide (AgInS2) quantum dots (QDs) improved the antibacterial activity against Gram-negative (Escherichia coli and Pseudomonas aeruginosa), and Gram-positive (Bacillus subtilis, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus) bacteria. The ADEP1 analogues exhibited minimum inhibition concentrations (MIC) between 63 and 500 µM, and minimum bactericidal concentrations (MBC) values between 125 and 750 µM. The AgInS2-ADEP1 analogue conjugates showed enhanced antibacterial activity as evident from the MIC and MBC values, i.e., 1.6–25 µM and 6.3–100 µM, respectively. The AgInS2-ADEP1 analogue conjugates were non-toxic against HEK-293 cells at concentrations that showed antibacterial activity. The findings reported herein could be helpful in the development of antibacterial treatment strategies.
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    Development of gold nanoparticles based lateral flow assay for detection of food and water-borne pathogens
    (Universty of the Western Cape, 2024) Mabhude, Yandiswa; Sibuyi, Nicole
    Food and water are two of the necessities required for survival. With increasing global population, urbanization, and climate change, to name a few, the strain on these two precious resources puts pressure on health as well as the economic sector. Microbial contamination of food and water can lead to lethal infections that are detrimental to human health. More than 90% of reported food-borne illnesses were caused by bacterial species such as Staphylococcus, Salmonella, Campylobacter, Listeria, Bacillus etc. In the last decade, Salmonella was the leading cause of bacterial food-borne illnesses; followed by Campylobacter and Listeria. Listeriosis cases were reported in 2017 in Gauteng province, and the number of infected persons rapidly escalated nationwide prompting an investigation wherein a total of 937 cases were identified. Early detection of pathogens in food and water could prevent or slow down the spread of infections and deaths caused by consuming contaminated food and water. The laboratory and on-site approaches that are currently used for quality control technologies are precise and sensitive, but they have drawbacks such as being laborious and time-consuming. Therefore, there is an urgent need for approaches that may be utilized to detect microbial contaminations at a point-of-care (PoC), that are user-friendly, quick, robust, and sensitive. The use of gold nanoparticles (AuNPs)-based lateral flow assay (LFA) for the detection of these pathogens is gaining traction among researchers as an alternative to conventional methods for on-site testing in places where there is no proper infrastructure, particularly low-resourced areas. The current study aimed to develop an aptamer-AuNPs-based LFA for the detection of food and water pathogens at PoC.
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    Investigation of the anti-obesity effects of citrate-capped gold nanoparticles on 3T3-L1 cells and their genetic profiling
    (University of the Western Cape, 2023) Mbengashe, Anelisiwe; Sibuyi, Nicole
    The incidence and prevalence of obesity and its related diseases has nearly tripled and is increasing at an alarming rate worldwide. Several modern methods for the management and treatment of obesity are available, with anti-obesity drugs being the preferred choice. Despite the availability of anti-obesity drugs, their therapeutic capabilities are hampered by drug toxicity and undesirable side effects, implying the need for alternative therapies. Thus, nanotechnology-based strategies may provide a novel beneficial mediator in the management and treatment of obesity.