Browsing by Author "Retief, Johannes Daniel"
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- ItemTowards a Paper-based Biosensor to Distinguish Between Bacterial and Viral Infections(Stellenbosch : Stellenbosch University, 2019-04) Retief, Johannes Daniel; Perold, W. J.; Fourie, P. R.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.ENGLISH ABSTRACT: The increasing threat of antimicrobial resistance has become more prominent in recent years due to strains of common bacteria becoming resistant to the medication used to cure the infections they cause. One of the causes of this problem is the indiscriminate prescription of antibiotics to patients with ambiguous symptoms, breeding antimicrobial resistance. The current management strategy for this problem is to develop more effective means of distinguishing between bacterial and viral infections, and specifically to develop biosensors for this purpose. This project aimed to develop a low-cost paper-based electrochemical transistor sensor to measure and detect the concentration of C-reactive protein in solution, with the goal of the transducers being used to distinguish between bacterial and viral infections in patients with ambiguous symptoms. C-reactive protein is known to be one of a group of proteins with promise in aiding diagnosis of different types of infections, and was chosen for its relatively low cost when compared to the alternatives. An inkjet printing system was developed to aid in the manufacturing process. After extensive modification, a regular desktop inkjet printer was converted to a flatbed configuration and could print structures with a minimum size of 70 μm. Layers of printed material could be aligned with a repeatability of 25 μm. Following successful implementation of the printer, a method was developed to manufacture organic electrochemical transistors onto paper substrates using printed silver electrodes. The transistors were subsequently functionalised and antibodies specific to C-reactive protein were immobilised onto the transducer surface. The transducers were tested and found to respond to CRP concentrations between 2:5 μg.ml-1 and 19.5 ng.ml-1, and the transducers were capable of quantifying protein concentrations over most of the clinically relevant range of concentrations for CRP. This means that the project was successful in developing a low-cost paper-based transducer to potentially aid in the differentiation between viral and bacterial infections.