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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Environmental nano- and micro-plastics (NMPs) are highly diverse [2]. Accounting for this diversity is one of the main challenges to develop a comprehensive understanding of NMPs detection, quantification, fate, and risks [3]. Two major issues currently limit progresses within this field: (a) validation and broadening the current analytical tools (b) uncertainty with respect to NMPs occurrence and behaviour at small scales (< 20 micron). Tracking NMPs in environmental systems is currently limited to micron size plastics due to the size detection limit of the available analytical techniques. There are currently many uncertainties regarding detecting nanoplastics in real environmental systems, e.g. the inexistence of commercially available NMPs and incompatibility between them and those generated from plastic fragments degradation in the environment. Trying to tackle these problems some research groups synthesized NMPs dopped with metals inside [16]. However, even though elemental analysis techniques (ICP-MS) are rather sensitive, the low volume of these metals encapsulated in the nanoparticles make their detection rather challenging. At the same time, due to Sars-Cov-19 pandemic, nucleic acid identification technologies (LAMP, PCR) experienced a fast evolution and are able to provide detection at very low levels with very compact and reliable equipment. Nuclepar proposes the use of Electrohydrodynamic Atomization (EHDA) to generate NMPs coated with nucleic acids of different polymer types, sizes, and shapes, which can be used as support for detection of such particles using PCR-LAMP technology. If proven possible, Nuclepar might become a first step towards an easy NMPs detection tool. This knowledge will certainly impact current risk assessment tools, efficient interventions to limit emissions and adequate regulations related to NMPs.
