Portable smartphone-based fluorescent microscopes are becoming popular owing to their ability to provide major functionalities offered by regular benchtop microscopes at a fraction of the cost. However, smartphone-based microscopes are still limited to a single fluorophore, fixed magnification, the inability to work with a different smartphones, and limited usability to either glass slides or cover slips. To overcome these challenges, here we present a modular smartphone-based microscopic attachment. The modular design allows the user to easily swap between different sets of filters and lenses, thereby enabling utility of multiple fluorophores and magnification levels. Our microscopic smartphone attachment can also be used with different smartphones and was tested with Nokia Lumia 1020, Samsung Galaxy S9+, and an iPhone XS. Further, we showed imaging results of samples on glass slides, cover slips, and microfluidic devices. A 1951 USAF resolution test target was used to quantify the maximum resolution of the microscope which was found to be 3.9 μm. The performance of the smartphone-based microscope was compared with a benchtop microscope and we found an R 2 value of 0.99 using polystyrene beads and blood cells isolated from human blood samples collected from Robert Wood Johnson Medical Hospital. Additionally, to count the particles (cells and beads) imaged from the smartphone-based fluorescent microscope, we developed artificial neural networks (ANNs) using multiple training algorithms, and evaluated their performances compared to the control (ImageJ). Finally, we did ANOVA and Tukey's post-hoc analysis and found a p -value of 0.97 which shows that no statistical significant difference exists between the performance of the trained ANN and control (ImageJ).
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A Smartphone-Based Disposable Hemoglobin Sensor Based on Colorimetric Analysis
Hemoglobin is a biomarker of interest for the diagnosis and prognosis of various diseases such as anemia, sickle cell disease, and thalassemia. In this paper, we present a disposable device that has the potential of being used in a setting for accurately quantifying hemoglobin levels in whole blood based on colorimetric analysis using a smartphone camera. Our biosensor employs a disposable microfluidic chip which is made using medical-grade tapes and filter paper on a glass slide in conjunction with a custom-made PolyDimethylSiloaxane (PDMS) micropump for enhancing capillary flow. Once the blood flows through the device, the glass slide is imaged using a smartphone equipped with a custom 3D printed attachment. The attachment has a Light Emitting Diode (LED) that functions as an independent light source to reduce the noise caused by background illumination and external light sources. We then use the RGB values obtained from the image to quantify the hemoglobin levels. We demonstrated the capability of our device for quantifying hemoglobin in Bovine Hemoglobin Powder, Frozen Beef Blood, and human blood. We present a logarithmic model that specifies the relationship between the Red channel of the RGB values and Hemoglobin concentration.
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- PAR ID:
- 10390376
- Date Published:
- Journal Name:
- Sensors
- Volume:
- 23
- Issue:
- 1
- ISSN:
- 1424-8220
- Page Range / eLocation ID:
- 394
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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A novel electrochemical glucose sensor was created for a simple but semiquantitative visual screening of specific glucose concentrations in urine. This noninvasive glucose biosensor integrated a disposable, paper-based sensing strip and a simple amplifier circuit with a visual readout. The paper strip consisted of five enzyme-activated electrodes. Each electrode was connected to a specific indicator circuit that triggered a light-emitting diode (LED) when a predefined glucose concentration was reached. The device features (1) low-cost, disposable, paper-based glucose oxidase (GOx)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) sensing electrodes, (2) simple signal amplification, and (3) on-site, rapid, and visual detection. The sensor generated reliable, discrete visual responses to determine five glucose levels (1, 2, 3, 4, and higher than 4 mM) in urine in less than 2 min. This innovative approach will provide a simple but powerful glucose sensing paradigm for use in POC diagnostics.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/s23010394
