Efficacy of a Novel Microelectronic Device Against an Endodontic Biofilm in a Tooth Model

Introduction: This study was a follow-up on a previous experiment which showed a statistically significant reduction in bacterial viability when using electrochemical disinfection on a single-species bacterial biofilm cultured in a 96-well plate. The purpose of this study was to investigate the effectiveness of electrochemical disinfection when using a tooth model cultured with a mixed-species bacterial biofilm. Methods: A total of 60 single-canal permanent teeth were cut to 15mm in length and cultured with a mixed-species biofilm containing Enterococcus faecalis, Fusobacterium nucleatum, and Porphyromonas gingivalis. They were then divided into five groups. Group 1 tooth samples were irrigated with phosphate-buffered saline (PBS), group 2 tooth samples were irrigated with PBS in combination with electrochemical disinfection (EC), group 3 tooth samples were irrigated with 1.5% NaOCl, group 4 tooth samples were irrigated with 1.5% NaOCl in combination with EC, and group 5 tooth samples were irrigated with 6% NaOCl. Results: There was a statistically significant 80.7% reduction in bacterial viability in group 2 compared to group 1. There were no statistically significant differences with respect to bacterial viability between groups 2 - 5. Conclusions: EC was found to be effective in reducing bacterial viability in a tooth model when used with PBS; however, no statistically significant bacterial viability reduction was identified when EC was combined with NaOCl compared with EC alone or NaOCL alone

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<p>Selective and rapid detection of biomarkers is of utmost importance in modern day health care for early stage diagnosis to prevent fatal diseases and infections. Among several protein biomarkers, the role of lysozyme has been found to be especially important in human immune system to prevent several bacterial infections and other chronic disease such as bronchopulmonary dysplasia. Thus, real-time monitoring of lysozyme concentration in a human body can pave a facile route for early warning for potential bacterial infections. Here, we present for the first time a label-free lysozyme protein sensor that is rapid and selective based on a graphene field-effect transistor (GFET) functionalized with selectively designed single-stranded probe DNA (pDNA) with high binding affinity toward lysozyme molecules. When the target lysozyme molecules bind to the surface-immobilized pDNAs, the resulting shift of the charge neutrality points of the GFET device, also known as the Dirac voltage, varied systematically with the concentration of target lysozyme molecules. The experimental results show that the GFET-based biosensor is capable of detecting lysozyme molecules in the concentration range from 10 nM to 1 µM.</p