Saliva diagnostics have become increasingly popular due to their non-invasive nature and patient-friendly collection process. Various collection methods are available, yet these are not always well standardized for either quantitative or qualitative analysis. In line, the objective of this study was to evaluate if measured levels of various biomarkers in the saliva of healthy individuals were affected by three distinct saliva collection methods: 1) unstimulated saliva, 2) chew stimulated saliva, and 3) oral rinse. Saliva samples from 30 healthy individuals were obtained by the three collection methods. Then, the levels of various salivary biomarkers such as proteins and ions were determined. It was found that levels of various biomarkers obtained from unstimulated saliva were comparable to those in chew stimulated saliva. The levels of potassium, sodium, and amylase activity differed significantly among the three collection methods. Levels of all biomarkers measured using the oral rinse method significantly differed from those obtained from unstimulated and chew-stimulated saliva. In conclusion, both unstimulated and chew-stimulated saliva provided comparable levels for a diverse group of biomarkers. However, the results obtained from the oral rinse method significantly differed from those of unstimulated and chew-stimulated saliva, due to the diluted nature of the saliva extract.
Standard SARS-CoV-2 testing protocols using nasopharyngeal/throat (NP/T) swabs are invasive and require trained medical staff for reliable sampling. In addition, it has been shown that PCR is more sensitive as compared to antigen-based tests. Here we describe the analytical and clinical evaluation of our in-house RNA extraction-free saliva-based molecular assay for the detection of SARS-CoV-2. Analytical sensitivity of the test was equal to the sensitivity obtained in other Dutch diagnostic laboratories that process NP/T swabs. In this study, 955 individuals participated and provided NP/T swabs for routine molecular analysis (with RNA extraction) and saliva for comparison. Our RT-qPCR resulted in a sensitivity of 82,86% and a specificity of 98,94% compared to the gold standard. A false-negative ratio of 1,9% was found. The SARS-CoV-2 detection workflow described here enables easy, economical, and reliable saliva processing, useful for repeated testing of individuals.
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from the article: "Abstract: The oral mucosa is the first immune tissue that encounters allergens upon ingestion of food. We hypothesized that the bio-accessibility of allergens at this stage may be a key determinant for sensitization. Light roasted peanut flour was suspended at various pH in buffers mimicking saliva. Protein concentrations and allergens profiles were determined in the supernatants. Peanut protein solubility was poor in the pH range between 3 and 6, while at a low pH (1.5) and at moderately high pHs (>8), it increased. In the pH range of saliva, between 6.5 and 8.5, the allergens Ara h2 and Ara h6 were readily released, whereas Ara h1 and Ara h3 were poorly released. Increasing the pH from 6.5 to 8.5 slightly increased the release of Ara h1 and Ara h3, but the recovery remained low (approximately 20%) compared to that of Ara h2 and Ara h6 (approximately 100% and 65%, respectively). This remarkable difference in the extraction kinetics suggests that Ara h2 and Ara h6 are the first allergens an individual is exposed to upon ingestion of peanut-containing food. We conclude that the peanut allergens Ara h2 and Ara h6 are quickly bio-accessible in the mouth, potentially explaining their extraordinary allergenicity."
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The continuous monitoring of health indicators in biofluids such as sweat, saliva, blood, and urine has great potential for preventive medicine. Techniques that continuously monitor biomarkers still remain a major technological challenge. Recently, a concept of dynamic biosensing was published that is based on mediator particles. Such mediator particles exhibit rapid switching between a bound and unbound state during interaction with a probing structure to which they are connected through a molecular tether (like a balloon on a string). Although the concept of using mediator particles for dynamics biosensing is very promising, the used detection method is not a viable solution as it is not miniaturizable. We propose to use a photonic ring resonator (RR) or Mach-Zender interferometer (MZI) as the probing structure in combination with a highly miniaturizable readout scheme. In this project, we perform preliminary experiments to prove that this photonic approach can be used for the detection of the mediator particles tethered to the photonic waveguide. To bridge the gap with the practical application by health professionals, we will enrich the envisioned solution through OnePlanet's OpenEd program. OpenEd aims to share technology and innovations (e.g. prototypes) with educational institutes (MBO, HBO) that want to further innovate their courses or work methods, such that current and future professionals are well prepared to work with new (digital) technologies. By presenting our use-case as a 'challenge' to teachers, students and practitioners, OpenEd also allows enriching the use-case by involving (future) health professionals that can provide feedback on - or further investigation of - the practical application of our new technology from the health professional's perspective.
