This study introduced a barcode-like design into a paper-based blood typing device by integrating with smartphone-based technology. The concept of presenting a paper-based blood typing assay in a barcode-like pattern significantly enhanced the adaptability of the assay to the smartphone technology. The fabrication of this device involved the use of a printing technique to define hydrophilic bar channels which were, respectively, treated with Anti-A, -B, and -D antibodies. These channels were then used to perform blood typing assays by introducing a blood sample. Blood type can be visually identified from eluting lengths in bar channels. A smartphone-based analytical application was designed to read the bar channels, analogous to scanning a barcode, interpret this information, and then report results to users. The proposed paper-based blood typing device is rapidly read by smartphones and easy for the user to operate. We envisage that the adaptation of paper-based devices to the widely accepted smartphone technology will increase the capability of paper-based diagnostics with rapid assay result interpretation, data storage, and transmission.

If a paper-based analytical device (μ-PAD) could be made by printing indicators for detection of heavy metals in chemical symbols of the metals in a style of the periodic table of elements, it could be possible for such μ-PAD to report the presence and the safety level of heavy metal ions in water simultaneously and by text message. This device would be able to provide easy solutions to field-based monitoring of heavy metals in industrial wastewater discharges and in irrigating and drinking water. Text-reporting could promptly inform even nonprofessional users of the water quality. This work presents a proof of concept study of this idea. Cu(II), Ni(II), and Cr(VI) were chosen to demonstrate the feasibility, specificity, and reliability of paper-based text-reporting devices for monitoring heavy metals in water.

The changes were studied in microbiological, chemical, and sensory properties of Pacific oysters stored at 10°C, 5°C, and 0°C. Pseudomonas (22%) and Vibrionaceae (20%) species were dominant in raw oysters. The dominant bacteria found in the spoiled samples were Pseudomonas regardless of the storage temperature. During storage, rapid increases in aerobic plate count (APC) values of the samples stored at 10°C and 5°C were observed, while no obvious lag phases were detected. With the samples stored at 0°C, a decrease in APC value during the first 4 days and a lag phase of about 6 days were observed. The APC values of the samples stored at 10°C, 5°C, and 0°C reached the level of 10 7 CFu/g on day 6, 10, and 18, respectively. All the tested samples stored at different temperatures revealed a slight decrease in pH and a significant increase of total volatile basic nitrogen (TVB-N) during storage. The average TVB-N concentration of about 22.0 mg N/100 g was observed at the end of the shelf-life as determined by APC. Combined with the sensory assessments, the shelf-life of 6-7, 10-11, and 17-18 days for oysters stored at 10°C, 5°C, and 0°C, respectively, was determined.

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This work describes a design strategy to scale up microfluidics for producing monodispersed emulsions. Scale-up to 180 microfluidic devices with tight distribution of droplet size has been achieved (coefficient of variation CV ∼ 5%) by designing a system that is capable of operating easily without active control on single devices within the microfluidic platform. This has been achieved by using existing knowledge gained in the formation of monodispersed emulsions using a single device. We have identified three important factors affecting the scale-up of microfluidic systems that can benefit industrial scale-up processing. First, we used a network model simulation (Matlab) to evaluate two different branching layouts used to distribute liquids from a single manifold into the parallelized device network. We checked how fabrication tolerances could affect droplet formation, and as a result of this step, the ladder-type layout was preferred to the tree-type arrangement. The second important contribution of this work is the introduction of separate drainage manifolds for the two phases connecting all the input streams which have improved the performance and the operability of the system. Finally, we introduced a large opening after a short channel (150 μm) downstream of the junction where the droplet is formed. This opening acts like a reservoir to damp any pressure variation which could travel back to the inlet point and disturb the flow of neighboring devices.