Introduction: The WHO has stated that about 50% of the world lacks access to secure and continuous supply of electricity, heavily impacting the healthcare industry in these countries. Microbial Fuel Cells (MFCs) can be a low cost-efficient energy source capable of powering medical devices in low-income countries. Due to the components and impurities found in saliva, this biofluid can behave like an electrolyte and a viable fuel source to power the MFC. With this capability, saliva has the potential to power micro-gadgets with microbial fuel cells capable of degrading the components of saliva. Thus, this study explores saliva’s potential to act as a fuel source to power microbial fuel cells within medical diagnosis devices.
Methods: A systematic review was conducted through primary and secondary research articles exploring and comparing the use of saliva as an energy source compared to other biofluids. Key terms focused for meta-analyses include: ‘semiconductors’, ‘saliva’, ‘microbial fuel cells’, ‘point-of-care’.
Results: Previous research has discovered that lysozyme enzymes present in saliva can create an electrical charge that can successively power biomedical devices. Researchers have also created paper-based batteries containing frozen exoelectrogenic cells, powered by the bacterial degradation of human spit. Saliva has been demonstrated to contain similar biomarkers to urine, a successful diagnostic biofluid, and can therefore be used as a diagnostic biofluid as well.
Discussion: Given saliva’s capabilities, a hypothetical diagnostic device powered using saliva as the biofluid, was designed. Bacteria break down the saliva, allowing protons to travel from the anode to the cathode resulting in electricity. It was determined that graphite would be the most cost-efficient and energy producing electrode material for the device. In addition, this electricity that is produced will power the diagnostic device attached.
Conclusion: Saliva can act as a fuel source, capable of powering diagnostic devices using microbial fuel cells with saliva. These properties can be beneficial to many people who do not have access to preliminary diagnosis. This can result in immediate treatment and help prevent further spread of diseases, vital for those in low-income countries. Broad scale applications of using saliva can be directed towards exterior lighting systems and powering larger medical devices.
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