On-Site Remote Monitoring System with NIR Signal-Based Detection of Infectious Disease Virus in Opaque Salivary Samples.

Infectious disease viruses, such as foot-and-mouth disease virus (FMDV), are highly contagious viruses that cause significant socioeconomic damage upon spreading. Developing an on-site diagnostic tool for early clinical detection and real-time surveillance of FMDV outbreaks is essential to prevent the further spread of the disease. However, early diagnosis of FMDV is still challenging due to the limited sensitivity and time-consuming manual result entry of commercial on-site tests for salivary samples. Here, we report a near-infrared (NIR) signal nanoprobe-based highly accurate detection and remote monitoring system toward FMDVs, which automates the analysis and reporting of diagnosis data. The NIR signal lateral flow immunoassay (LFA) was assembled with a nanoprobe with a stable emission intensity at 800 nm, minimizing the interference signal of opaque salivary samples. We investigated the clinical applicability of the NIR signal LFA at biosafety level 3 (BSL-3) laboratories using 147 opaque salivary samples. The NIR signal LFA achieved a 32-fold lower limit of detection (LOD) than a commercial LFA in detecting live FMDVs, including all isolates occurring in the Republic of Korea during 2010-2017. Our results showed that the NIR signal LFA successfully discriminated the FMDV-positive clinical salivary samples from healthy controls with a sensitivity of 96.9%, specificity of 100.0%, and AUC (area under the receiver operator characteristic curve) value of 0.999. Finally, we substantiated the real-time collection of diagnostic results using a customized portable NIR reader at nine different laboratories of government-certified quarantine institutions for foot-and-mouth disease (FMD).

Normalizing the Optical Signal Enables Robust Assays with Lateral Flow Biosensors.

Lateral flow assays (LFAs) are widely adopted for fast, on-site molecular diagnostics. Obtaining high-precision assay results, however, remains challenging and often requires a dedicated optical setup to control the imaging environment. Here, we describe quick light normalization exam (qLiNE) that transforms ubiquitous smartphones into a robust LFA reader. qLiNE used a reference card, printed with geometric patterns and color standards, for real-time optical calibration: a photo of an LFA test strip was taken along with the card, and the image was processed using a smartphone app to correct shape distortion, illumination brightness, and color imbalances. This approach yielded consistent optical signal, enabling quantitative molecular analyses under different illumination conditions. We adapted qLiNE to detect cortisol, a known stress hormone, in saliva samples at point-of-use settings. The assay was fast (15 min) and sensitive (detection limit, 0.16 ng/mL). The serial qLiNE assay detected diurnal cycles of cortisol levels as well as stress-induced cortisol increase.

All Ink-Jet Printed P3HT:PCBM Organic Solar Cells on ITO-Coated Glass Substrate.

Printed electronics have surfaced with a lot of interest recently. This paper reports development of a non vacuum process for fabricating poly(3-hexylthiophene):[6,6]-pheny-C61-butyric acid methyl ester organic solar cells (OSCs) using ink-jet printing technique. The printing conditions of different layers were optimized to avoid the coffee ring effect and the Marangoni effect. The effect of substrate's temperature and drop spacing size was compared to obtain uniform layers. We controlled the substrate temperature ranging from 30 degrees C to 80 degrees C and varied the spacing size between two lines ranging from 10 µm to 80 µm during printing. The device characteristics were analyzed using alpha step and solar simulator. The optimized printed conditions for ZnO are 50 degrees C substrate temperature and 50 µm spacing size. For the active layer, PEDOT: PSS and Ag electrode, the optimized conditions are 50 degrees C/50 µm, 30 degrees C/30 µm and 80 degrees C/80 µm, respectively. The power conversion efficiency of the OSCs fabricated with optimized printing condition is 1.25%.