abstract: Abnormally low or high blood iron levels are common health conditions worldwide and can seriously affect an individual’s overall well-being. A low-cost point-of-care technology that measures blood iron markers with a goal of both preventing and treating iron-related disorders represents a significant advancement in medical care delivery systems. Methods: A novel assay equipped with an accurate, storable, and robust dry sensor strip, as well as a smartphone mount and (iPhone) app is used to measure total iron in human serum. The sensor strip has a vertical flow design and is based on an optimized chemical reaction. The reaction strips iron ions from blood-transport proteins, reduces Fe(III) to Fe(II), and chelates Fe(II) with ferene, with the change indicated by a blue color on the strip. The smartphone mount is robust and controls the light source of the color reading App, which is calibrated to obtain output iron concentration results. The real serum samples are then used to assess iron concentrations from the new assay and validated through intra-laboratory and inter-laboratory experiments. The intra-laboratory validation uses an optimized iron detection assay with multi-well plate spectrophotometry. The inter-laboratory validation method is performed in a commercial testing facility (LabCorp). Results: The novel assay with the dry sensor strip and smartphone mount, and App is seen to be sensitive to iron detection with a dynamic range of 50 - 300 µg/dL, sensitivity of 0.00049 µg/dL, coefficient of variation (CV) of 10.5%, and an estimated detection limit of ~15 µg/dL These analytical specifications are useful for predicting iron deficiency and overloads. The optimized reference method has a sensitivity of 0.00093 µg/dL and CV of 2.2%. The correlation of serum iron concentrations (N=20) between the optimized reference method and the novel assay renders a slope of 0.95, and a regression coefficient of 0.98, suggesting that the new assay is accurate. Lastly, a spectrophotometric study of the iron detection reaction kinetics is seen to reveal the reaction order for iron and chelating agent. Conclusion: The new assay is able to provide accurate results in intra- and inter- laboratory validations and has promising features of both mobility and low-cost. / Dissertation/Thesis / Doctoral Dissertation Chemical Engineering 2020

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Preventing the spread of blood-borne infectious diseases is vital to improving global health outcomes, particularly for low- and middle-income countries (LMICs). Sensitive and accurate diagnosis of infections is vital to this effort. Nucleic acid amplification tests (NAATs), which amplify pathogen nucleic acids, are gold-standard techniques for detection and quantification of pathogen levels. However, standard NAATs such as polymerase chain reaction (PCR) require expensive equipment for blood sample processing and DNA/RNA amplification, making them challenging to implement in resource-limited areas of LMICs. In this work, I developed two methods to simplify sample processing and amplification to make NAATs more accessible for use at the point of care in resource-limited areas of LMICs. The first method enables instrument-free nucleic acid extraction from whole blood. A room temperature lysis chemistry and a paper-and-plastic sample capture device were developed to isolate, purify, and store pathogen DNA and RNA on a paper capture membrane. Extracted nucleic acids can be eluted and used in standard NAATs or in developmental amplification assays. I demonstrated successful isolation of HIV virion RNA and P. falciparum parasite DNA from whole blood samples over several concentrations with >60% recovery. Extracted RNA remains stable on the capture membrane for two weeks at room temperature and 37°C, alleviating the need for cold storage after sample collection. These results are a promising step toward using this method for simplified sample extraction and storage in low-resource settings in LMICs. The second method I developed is a novel isothermal amplification technique for P. falciparum DNA. Sensitive diagnosis of P. falciparum infection is vital to identify and treat low-density, asymptomatic infections and move closer to eliminating malaria. Highly sensitive PCR assays are difficult to deploy in resource-limited areas of LMICs and existing isothermal methods require complex assay design and are often not sensitive enough to diagnose asymptomatic infections. Here, I developed a novel isothermal technique which amplifies multiple regions of the P. falciparum genome, generating a large amount of DNA for better analytical sensitivity. The assay achieves a lower limit of detection of ~23.4 fg P. falciparum gDNA/µL (~1 parasite/µL) in 30 minutes, similar gold-standard PCR assay while using a fraction of the resources required for PCR. Lastly, I adapted the assay for implementation at the point of care. I showed that the assay directly amplifies P. falciparum parasite DNA captured on paper with the paper-and-plastic device previously developed. I also incorporated visual assay readout with lateral flow strips, eliminating the need for specialized equipment to detect amplified DNA. I explored methods to eliminate cold storage of reagents by stabilizing amplification enzymes at room temperature. The work described in this thesis represents two enhanced methods for point of care detection of blood borne pathogens. By simplifying sample extraction, amplification, and detection, the methods described here make NAATs more accessible to low-resource areas of LMICs. The whole blood nucleic acid extraction device and isothermal assay described in this work can be used together for sensitive diagnosis of P. falciparum malaria. The methods can also be used independently, or in combination with other techniques routinely used in the field. The flexibility built in to these methods enables easier integration into existing workflows in LMICs. / 2021-05-18T00:00:00Z

During the last years many mobile health applications have emerged on the market. Most of these collect and compiles physical data that can be followed over time. Now the next generation of health care applications are on their way. With an increasing capacity and high quality sensors, smartphones have the potential to be used as diagnostic tools. Calmark Sweden AB is a company that has developed a smartphone based diagnostic platform for analysis of colorimetric assays integrated on a disposable plastic chip. Their first product, the hilda Neo system is a Point of care test (POCT) for semi quantitative measurement of the biomarker Lac- tate dehydrogenase (LDH). The system consists of a disposable colorimetric LDH test with inte- grated chemical assay, a separate light-box for controlled light conditions and a smartphone appli- cation for image acquisition and test analysis. The purpose of this Master Thesis project was to develop and evaluate a method for smartphone based semi quantitative colorimetric analysis of the hilda Neo LDH test that would work without the light-box in different light settings. The method was to be implementable as an iPhone applica- tion and should be able do correctly determine LDH activity in the four LDH ranges; 0-300, 300- 600, 600-900 and >900 units per litre (U/L). Also, the computed LDH levels among cards run with the same sample were not to have a standard deviation higher than 50 U/L. Two methods based on continuous measurements of the colour stimuli given from the assay site were developed. In both methods, measurements were made by using the iPhone camera for taking an image series following the colour development of the assay over time. The image series was then processed in MATLAB and the LDH level was computed in two different ways. None of the two proposed methods did reach the stated objectives. Neither of the methods gave the correct LDH interval in all evaluation cards and the computed LDH levels had a larger standard deviation then aimed for. However the results indicate that the variation in light settings is not the only factor for the unreached objectives. It is believed that with further studies of the colour proper- ties of the hilda Neo assay and with the continuing development of smartphone technology, it is possible to find a method for smartphone-based colorimetric analysis without having to control the light setting. / Under de senaste åren har många hälso-applikationer introducerats på marknaden. De flesta samlar och sammanställer hälso-data som sedan kan följas över tiden. Nu är en ny generation av hälso- applikationer på ingång. Med ökande kapacitet och högkvalitativa sensorer har våra smartphones potential att användas för medicinsk diagnostik. Calmark Sweden AB är ett företag som har utvecklat en smartphone-baserad diagnostisk plattform för analys av kolorimetriska tester i form av plastkort för engångsbruk. Deras första produkt hilda Neo är ett patientnära test för semikvantitativ mätning av biomarkören Lactatdehydrogenas (LDH). Systemet består av det kolorimetriska engångstestet för mätning av LDH, en separat ljus-box för kontrollerade ljusförhållanden och en smartphone applikation för bildtagning och test analys. Målet med detta masterexamensarbete var att utveckla och utvärdera en metod för smartphone- baserad semikvantitativ kolorimetrisk analys av hilda Neo testet som fungerar utan ljus-box i olika ljussättningar. Metoden skulle vara implementerbar som en iPhone applikation och skulle kunna bestämma LDH aktivitet inom fyra intervall; 0-300, 300-600, 600-900 och >900 enheter per liter (U/L). De beräknade LDH nivåerna för kort körda med samma prov skulle inte heller ha en standardavvikelse över 50 U/L. Två metoder baserade på kontinuerlig mätning av provets färgutveckling togs fram. För båda metoderna användes iPhone kameran för att ta en bildserie som följde testets färgutveckling över tiden. Bildserien behandlades sedan i MATLAB och ett LDH värde beräknades med de två olika metoderna. Ingen av de två föreslagna metoderna uppnådde de uppsatta målen. Ingen av metoderna gav rätt LDH intervall för alla kort som användes för utvärdering och de beräknade LDH nivåerna hade en för hög standard avvikelse. Dock indikerade resultaten på att variationer i ljussättningen inte var den enda faktorn som bidrog till de ouppnådda målen. Författaren tror att med fortsatt studerande av hilda Neo testets färgegenskaper och med den fortlöpande utvecklingen av smartphone tekniken, kommer det att vara möjligt att hitta en metod för smartphone-baserad kolorimetrisk analys utan kontrollerad ljussättning.

The outbreak of infectious diseases across the world results in huge disasters for public health. Rapid and effective diagnostic methods are crucial for disease identification and transmission control. Since first identified in late 2019, the pandemic of COVID-19 caused by the SARS-CoV-2 virus resulted in unprecedented catastrophe globally. To control the further spread of COVID-19, there is an urgent need for rapid, accurate, cost-effective, and efficient diagnostics. Recently, many CRISPR-based diagnostics have been developed by coupling isothermal amplification methods with Cas proteinmediated nucleic acid detection. Compared with conventional methods like RT-qPCR, CRISPR-based assays are more cost-effective and efficient without sacrificing sensitivity and specificity. Here, I developed a Cas13-based assay for SARS-CoV-2 detection with a novel compact Cas13b protein. In this assay, the Cas13 detection is combined with RT-LAMP, achieving the detection of viral RNA as low as 4 copies/μl. By utilizing a simple LED-based visualizer (P51™) instead of a plate reader, the detection result can be visualized directly without using sophisticated instruments. The compact Cas13b-mediated viral detection together with P51™-based visualization enable rapid, sensitive, and portable diagnostics for SARS-CoV-2, showing great potential in application to point-of-care testing.

Elsevier is a leading publisher of medical content, and ClinicalKey is the company's latest endeavor to aggregate multiple resources in one easily searchable interface. ClinicalKey merges medical education with clinically relevant information. This review will provide an overview of the contents, search options, features and limitations of this database.

Elsevier is a leading publisher of medical content, and ClinicalKey is the company's latest endeavor to aggregate multiple resources in one easily searchable interface. ClinicalKey merges medical education with clinically relevant information. This review will provide an overview of the contents, search options, features and limitations of this database.

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