(a) A schematic of the desired portable image-recording device, which contains an LED (yellow square in the center of white square), a battery (rectangular with gradient gray), and a plastic shell with two slots on both sides. (b) A schematic of the desired portable device combined with a cellphone and a paper stripe. (c) A schematic of the basic design components for fluorescence detection, using the camera system of a cellphone.

Contexts in source publication

Context 1

... experimental images were captured using the built-in camera software, in an array of different smartphones. Camera focus during image capture was set on the center of each single spot (bright area) for single-spot detection, and on the center of each four-spot test (dark area) for multi-spot detection, to diminish the intensity variations caused by the native auto-adjusting functions of each smartphone. Captured images were exported to a computer and saved in JPEG format. The mean intensity of each exported image was analyzed with free public software (ImageJ, Ver. 1.49q), and was presented as a mean value with a standard deviation (Mean ? S.D.). The Student's t-test was employed to analyze the significant difference between two experimental groups. A p-value is the probability that the results from the sample data occurred by chance. In general, lower p-values indicate higher significant difference between two groups. A p-value of 0.05 indicates only a 5% difference, which is an acceptable difference, indicating that the data is valid. Figure 1a,b provide an overview of the portable imaging device, as follows: (i) UV-LED; (ii) a battery; (iii) a plastic shell with two slots on both sides for inserting a light filter; (iv) an observation hole for a paper device; and (v) a cellphone attachment. UV light (405 nm) from the LED chip penetrated through the PAD and light filter, and the final transmission light was recorded via a cellphone camera (Figure 1c). Additional elements included assembled electronic components on a printed circuit board (PCB) with a light adjuster and UV-LEDs in a black plastic box, for our fluorescence imaging device. The circuit on the PCB controlled UV-LED power output and manipulated light intensity (Figure 2). The regulator allowed us to modulate direct current (DC) voltage in the range of 9 V to 5 V, to accommodate a microcontroller unit (MCU). The function of the N-type MOSFET was to amplify power. Following pulse-width modulation methodology, the voltage signal was manually controlled by adjusting resistance, and could be converted to 8-bit digital signals corresponding to 0-100% of the duty cycle. The purpose of the power-modulated circuit was to regulate UV-LED intensity, and to determine the appropriate wavelength for excitation of fluorescent components. Peak wavelength from the manufacturer-provided UV-LED data sheet reported that the LED light emitted light ranging from 400 nm to 410 nm, but our measurements with a spectrometer indicated that the wavelength of emitted light had a peak intensity slightly less than 400 nm (Figure 3). We also employed sunlight as a standard reference to ensure normal spectrometer function; the wavelength of sunlight was measured, as shown in Figure 3b. In addition to confirming the emitted UV-LED wavelength, the wavelength of light penetrating our filters was also verified. Two light filters, band-pass 600 nm (600 ? 80 nm) and long-pass 500 nm (>500 nm), were selected for fluorescent light filtration in the DNA quantitative experiment and semen assay, sequentially. Figure 3c,d, depict the wavelength measurement of sunlight penetrating through band-pass 600 nm and long-pass 500 nm, sequentially. These measured results indicate that the filtered light wavelengths corresponded to wavelengths provided by the manufacturer-provided filter datasheets. The wavelength of sunlight penetrating through a band-pass 600 nm filter and a long-pass 500 nm filter, ...

Context 2

... experimental images were captured using the built-in camera software, in an array of different smartphones. Camera focus during image capture was set on the center of each single spot (bright area) for single-spot detection, and on the center of each four-spot test (dark area) for multi-spot detection, to diminish the intensity variations caused by the native auto-adjusting functions of each smartphone. Captured images were exported to a computer and saved in JPEG format. The mean intensity of each exported image was analyzed with free public software (ImageJ, Ver. 1.49q), and was presented as a mean value with a standard deviation (Mean ? S.D.). The Student's t-test was employed to analyze the significant difference between two experimental groups. A p-value is the probability that the results from the sample data occurred by chance. In general, lower p-values indicate higher significant difference between two groups. A p-value of 0.05 indicates only a 5% difference, which is an acceptable difference, indicating that the data is valid. Figure 1a,b provide an overview of the portable imaging device, as follows: (i) UV-LED; (ii) a battery; (iii) a plastic shell with two slots on both sides for inserting a light filter; (iv) an observation hole for a paper device; and (v) a cellphone attachment. UV light (405 nm) from the LED chip penetrated through the PAD and light filter, and the final transmission light was recorded via a cellphone camera (Figure 1c). Additional elements included assembled electronic components on a printed circuit board (PCB) with a light adjuster and UV-LEDs in a black plastic box, for our fluorescence imaging device. The circuit on the PCB controlled UV-LED power output and manipulated light intensity (Figure 2). The regulator allowed us to modulate direct current (DC) voltage in the range of 9 V to 5 V, to accommodate a microcontroller unit (MCU). The function of the N-type MOSFET was to amplify power. Following pulse-width modulation methodology, the voltage signal was manually controlled by adjusting resistance, and could be converted to 8-bit digital signals corresponding to 0-100% of the duty cycle. The purpose of the power-modulated circuit was to regulate UV-LED intensity, and to determine the appropriate wavelength for excitation of fluorescent components. Peak wavelength from the manufacturer-provided UV-LED data sheet reported that the LED light emitted light ranging from 400 nm to 410 nm, but our measurements with a spectrometer indicated that the wavelength of emitted light had a peak intensity slightly less than 400 nm (Figure 3). We also employed sunlight as a standard reference to ensure normal spectrometer function; the wavelength of sunlight was measured, as shown in Figure 3b. In addition to confirming the emitted UV-LED wavelength, the wavelength of light penetrating our filters was also verified. Two light filters, band-pass 600 nm (600 ? 80 nm) and long-pass 500 nm (>500 nm), were selected for fluorescent light filtration in the DNA quantitative experiment and semen assay, sequentially. Figure 3c,d, depict the wavelength measurement of sunlight penetrating through band-pass 600 nm and long-pass 500 nm, sequentially. These measured results indicate that the filtered light wavelengths corresponded to wavelengths provided by the manufacturer-provided filter datasheets. The wavelength of sunlight penetrating through a band-pass 600 nm filter and a long-pass 500 nm filter, ...