Mobile imaging platform for digital influenza virus counting

Minagawa, Yasuyo; Ueno, Hiroshi; Tabata, Kazuhito V.; Noji, Hiroyuki

doi:10.1039/c9lc00370c

Cited by 41 publications

(35 citation statements)

References 46 publications

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“…5,[33][34][35][36] In addition, many portable fluorescence imaging platforms have been developed, including smartphone attachments for imaging single fluorescent nanoparticles and RCA products, and can be readily adapted for dSimoa. 5,[37][38][39][40][41] While multiple frames were required to completely capture each dropcast film in this work, shorter imaging times should be possible using an automated hand-held reader or a wide field-of-view camera. Moreover, as supported by our sampling analysis of the dSimoa results, only ~20% of the total assay beads may need to be imaged to achieve close to maximal sensitivity.…”

Section: Discussionmentioning

confidence: 99%

Ultrasensitive Detection of Attomolar Protein Concentrations by Dropcast Single Molecule Assays

2020

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Measurements of very low levels of biomolecules, including proteins and nucleic acids, remain a critical challenge in many clinical diagnostic applications due to insufficient sensitivity. While digital measurement methods such as Single Molecule Arrays (Simoa), or digital ELISA, have made significant advances in sensitivity, there are still many potential disease biomarkers that exist in accessible biofluids at levels below the detection limits of these techniques. To overcome this barrier, we have developed a simple strategy for single molecule counting, dropcast single molecule assays (dSimoa), that enables more target molecules to be counted through increased sampling efficiency and with a simpler workflow. In this approach, beads are simply dropcast onto a microscope slide and dried into a monolayer film for digital signal readout. The dSimoa platform achieves attomolar limits of detection, with an up to 25-fold improvement in sensitivity over Simoa, the current state of the art for ultrasensitive protein detection. Furthermore, due to its simple readout process and improved cost-effectiveness compared to existing digital bioassays, dSimoa increases amenability to integration into point-of-care platforms. As an illustration of the potential utility of dSimoa, we demonstrate its ability to measure previously undetectable levels of Brachyury, a tissue biomarker for chordoma, in plasma samples. With its significantly enhanced sensitivity and simplicity, dSimoa can pave the way toward the discovery of new biomarkers for early disease diagnosis and improved health outcomes.

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Section: Discussionmentioning

confidence: 99%

Ultrasensitive Detection of Attomolar Protein Concentrations by Dropcast Single Molecule Assays

2020

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“…Uniformity in the compartment volumes ensures the reaction conditions are relatively similar and reactions across volumes can be compared. Microfluidic wells [1][2][3] or droplet generators [4][5][6] enable uniform compartmentalization of a sample fluid volume into many smaller reactions, however skilled users or specialized and costly commercial instruments have been required for reproducible implementation. In addition, for many affinity assays, a solid phase, such as microbeads, is desired to bind a target and allow washing to remove excess reagents or minimize non-specific binding.…”

Section: Introductionmentioning

confidence: 99%

Formation of uniform reaction volumes using concentric amphiphilic microparticles

Destgeer

Ouyang²,

Wu³

et al. 2020

Preprint

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Reactions performed in uniform microscale volumes have enabled numerous applications in the analysis of rare entities (e.g. cells and molecules), however, sophisticated instruments are usually required to form large numbers of uniform compartments. Here, uniform aqueous droplets are formed by simply mixing microscale multi-material particles, consisting of concentric hydrophobic outer and hydrophilic inner layers, with oil and water. The particles are manufactured in batch using a 3D printed device to co-flow four concentric streams of polymer precursors which are polymerized with UV light. The size of the particles is readily controlled by adjusting the fluid flow rate ratios and mask design; whereas the cross-sectional shapes are altered by microfluidic nozzle design in the 3D printed device. Once a particle encapsulates an aqueous volume, each "dropicle" provides uniform compartmentalization and customizable shape-coding for each sample volume to enable multiplexing of uniform reactions in a scalable manner. We implement an enzymatically-amplified affinity assay using the dropicle system, yielding a detection limit of <1 pM with a dynamic range of at least 3 orders of magnitude. Moreover, multiplexing using two types of shape-coded particles was demonstrated without cross talk, laying a foundation for democratized single-entity assays.

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“…Blood glucose concentration in diabetic patients [31], electrolytes concentration in human sweat [32], and alkaline phosphate concentration in dairy [33] and serum [34] samples have been quantified via smartphone images. Smartphone imaging has also been utilized in applications such as detecting nucleic acids [35], influenza virus counting [36], immunoassay of prostate specific antigens [37], and detection of Hg 2+ via smartphone fluorescence microscopy [38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Estimation of available epinephrine dose in expired and discolored autoinjectors via quantitative smartphone imaging

et al. 2020

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Epinephrine autoinjectors (EAIs) are important first aid medications for treating anaphylaxis. A 10-fold price increase over the past 12 years and evidence that expired EAIs may still contain significant doses of available epinephrine have motivated interest in the efficacy of expired EAIs as treatments of last resort. Degradation of expired EAIs, which can be caused by improper storage conditions, results in various degrees of discoloration of the epinephrine solution. Previous studies have determined that significant epinephrine remains available in expired EAIs, but these have only considered EAIs that show no discoloration. Here, we investigate the potential for colorimetric estimation of available epinephrine dose based on the degree of discoloration in expired EAIs. The correlation of available epinephrine dose and time since expiration date was poor (r = − 0.37), as determined by an industry standard UHPLC protocol. Visible absorbance of the samples integrated across the range 430-475 nm correlated well with available epinephrine dose (r = − 0.71). This wavelength corresponds to the blue channel of a typical smartphone camera Bayer filter. Smartphone camera images of the EAI solutions in various illumination conditions were analyzed to assign color indices representing the degree of discoloration. Color index of the samples showed similar correlation (|r| > 0.7) with available epinephrine dose as that of visible spectrophotometry. Smartphone imaging colorimetry is proposed as a potential point-of-use epinephrine dose estimator for expired and degraded EAIs.

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Mobile imaging platform for digital influenza virus counting

Abstract: A compact and simple smartphone-based mobile imaging platform realized swift single influenza virus counting of clinical samples.

Cited by 41 publications

References 46 publications

Ultrasensitive Detection of Attomolar Protein Concentrations by Dropcast Single Molecule Assays

Ultrasensitive Detection of Attomolar Protein Concentrations by Dropcast Single Molecule Assays

Formation of uniform reaction volumes using concentric amphiphilic microparticles

Estimation of available epinephrine dose in expired and discolored autoinjectors via quantitative smartphone imaging

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