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Design and fabrication of microfluidic devices on polymethylmethacrylate (PMMA) substrates for analytical chemistry and biomedical-related applications using novel microfabrication methods are described. The image of microstructures is transferred from quartz master templates possessing the inverse image of the devices to plastic plates by using hot embossing methods. The micro channels on quartz master templates are formed by the combination of metal etch mask and wet chemical etching of a photomask blank.The micromachined quartz templates can be used repeatedly to replicate cheap and disposable plastic devices. The reproducibility of the hot embossing method is evaluated using 10 channels on different PMMA plastics (Fig. 1). The relative standard deviation of the channel profile on the plastic chips is less than 1 %. In this study, the PMMA microfluidic chips have been demonstrated as a micro capillary electrophoresis (-CE) device for DNA separation and detection. The capability of the fabricated chip for electrophoretic injection and separation is characterized via the analysis of DNA fragments ΦX-174-RF Hae III digest. Experimental results indicate that all of the 11 DNA fragments of the size marker could be identified in less than 2 minutes with relative standard deviations less than 0.4 % and 8 % for migration time and peak area, respectively. Moreover, with the use of a near IR dye, fluorescence signals of the higher molecular weight fragments (> 603 bp in length) could be detected at total DNA concentrations as low as 0.1 g/mL. In addition to DNA fragments ΦX174-RF Hae III digest, DNA sizing of hepatitis C viral (HCV) amplicon is also achieved using microchip electrophoresis on PMMA substrates. Fig. 1 Picture of a micro electrophoresis chip fabricated by the hot embossing method.

An asymmetric supercapacitor with high energy was assembled by using the N-GNTs@OV-Bi2O3 NSAs and N-GNTs@CoNi2S4 NPs as negative and positive electrodes, respectively.

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This letter reports an optically induced cell lysis device that can selectively lyse a single cell within a group of cells, a function which cannot be performed using traditional tools. This chip-scale device was made of a photoconductive material, which can induce a nonuniform electric field at a specific position under illumination of a beam spot generating a transmembrane potential in the cell. With this approach, cell lysis can be performed using the optically induced electric field. Fibroblast cells and oral cancer cells were used to demonstrate the capability of the developed chip. In addition to lysing the whole cell, the developed method also allowed one to selectively disrupt the cell membrane without damaging the nucleus. Operating parameters such as illumination power density and beam spot diameter for cell lysis were systematically investigated.

Niemann-Pick type C disease (NPC) is a rare human disease, with limited effective treatment options. Most cases of NPC disease are associated with inactivating mutations of the NPC1 gene. However, cellular and molecular mechanisms responsible for the NPC1 pathogenesis remain poorly defined. This is partly due to the lack of a suitable animal model to monitor the disease progression. In this study, we used CRISPR to construct an NPC1-/- zebrafish model, which faithfully reproduced the cardinal pathological features of this disease. In contrast to the wild type (WT), the deletion of NPC1 alone caused significant hepatosplenomegaly, ataxia, Purkinje cell death, increased lipid storage, infertility and reduced body length and life span. Most of the NPC1-/- zebrafish died within the first month post fertilization, while the remaining specimens developed slower than the WT and died before reaching 8 months of age. Filipin-stained hepatocytes of the NPC1-/- zebrafish were clear, indicating abnormal accumulation of unesterified cholesterol. Lipid profiling showed a significant difference between NPC1-/- and WT zebrafish. An obvious accumulation of seven sphingolipids was detected in livers of NPC1-/- zebrafish. In summary, our results provide a valuable model system that could identify promising therapeutic targets and treatments for the NPC disease.

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