Paperfuge An ultra-low cost, hand-powered centrifuge inspired by the mechanics of a whirligig toy, bioRxiv, 2016-09-01

AbstractSample preparation, including separation of plasma from whole blood or isolation of parasites, is an unmet challenge in many point of care (POC) diagnostics and requires centrifugation as the first key step. From the context of global health applications, commercial centrifuges are expensive, bulky and electricity-powered, leading to a critical bottle-neck in the development of decentralized, electricity-free POC diagnostic devices. By uncovering the fundamental mechanics of an ancient whirligig toy (3300 B.C.E), we design an ultra-low cost (20 cents), light-weight (2 g), human-powered centrifuge that is made out of paper (“paperfuge”). To push the operating limits of this unconventional centrifuge, we present an experimentally-validated theoretical model that describes the paperfuge as a non-linear, non-conservative oscillator system. We use this model to inform our design process, achieving speeds of 125,000 rpm and equivalent centrifugal forces of 30,000 g, with theoretical limits predicting one million rpm. We harness these speeds to separate pure plasma in less than 1.5 minutes and isolate malaria parasites in 15 minutes from whole human blood. By expanding the materials used, we implement centrifugal microfluidics using PDMS, plastic and 3D-printed devices, ultimately opening up new opportunities for electricity-free POC diagnostics, especially in resource-poor settings.

biorxiv bioengineering 200-500-users 2016

Deep Sequencing of 10,000 Human Genomes, bioRxiv, 2016-07-02

AbstractWe report on the sequencing of 10,545 human genomes at 30-40x coverage with an emphasis on quality metrics and novel variant and sequence discovery. We find that 84% of an individual human genome can be sequenced confidently. This high confidence region includes 91.5% of exon sequence and 95.2% of known pathogenic variant positions. We present thedistribution of over 150 million single nucleotide variants in the coding and non-coding genome. Each newly sequenced genome contributes an average of 8,579 novel variants. In addition, each genome carries in average 0.7 Mb of sequence that is not found in the main build of the hg38 reference genome. The density of this catalog of variation allowed us to construct highresolution profiles that define genomic sites that are highly intolerant of genetic variation. These results indicate that the data generated by deep genome sequencing is of the quality necessary for clinical use.Significance statementDeclining sequencing costs and new large-scale initiatives towards personalized medicine are driving a massive expansion in the number of human genomes being sequenced. Therefore, there is an urgent need to define quality standards for clinical use. This includes deep coverage and sequencing accuracy of an individual’s genome, rather than aggregated coverage of data across a cohort or population. Our work represents the largest effort to date in sequencing human genomes at deep coverage with these new standards. This study identifies over 150 million human variants, a majority of them rare and unknown. Moreover, these data identify sites in the genome that are highly intolerant to variation - possibly essential for life or health. We conclude that high coverage genome sequencing provides accurate detail on human variation for discovery and for clinical applications.

biorxiv genomics 200-500-users 2016

 

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