Papers by Keyword: Microchips

Abstract: A novel multi-channel DNA fragment analysis system is presented，which is based on single PMT confocal fluorescence detection and optical scanning adopting an f-theta lens. Capillary electrophoresis experiments were executed in the system for DNA marker pBR322/Hae III. Signal was processed with wavelet denoising. The system’s limit of detection (dsDNA with the probe of Thiazole Orange, TO) was evaluated to be 1.1841×10-11mol/L. Its working noise is much lower compared with that based on mechanical scanning one, and the stability and detecting sensitivity is high. The system was expected to be applied to both capillary array and microchip electrophoresis detection based on laser-induced fluorescence.

Abstract: This study demonstrated that DNA associated with magnetic nanoparticles can be attracted to specific areas of cell surfaces under magnetic fields, which highly increased the DNA concentration at specific areas and further enhanced the gene transfection in an electroporation (EP) method. The superparamagnetic nanoparticle’s distribution could be operated by magnetic field, where the gravity effect could be neglected. Compared with the electroporation with and without electrostatic attracting force, the magneto-electroporation with magnetic attracting force showed higher delivery rate (63.05 %) in the electroporation processes. Simulating an asymmetric magnetic field helps to create experiment environment with different intensities of magnetic flux density. The resultant difference can be identified by the profile of fluorescence. This report focused on enhancement and targeting of gene transfection using 6 nm γ-Fe2O3 nanoparticles and electroporation microchips.

Abstract: Microfluidic devices are of considerable interest, since such technology offers great promise for the development of powerful and versatile miniaturized analyzers. Accordingly, the present work describes a microfluidic screening system that is composed of a microchip, hydrodynamic pumping unit and fluorescence detectors. To develop an assay for RNA-aminoglycoside interactions, microchips are designed and fabricated on a glass substrate, then flow simulations are performed in the microchannels. After optimizing the flow control and buffer composition for fluorescence-based biochemical assays, a fluorescently labeled aminoglycoside probe and RNA are allowed to flow continuously to the main micro-channel based on hydrodynamic pumping and their interactions monitored by fluorescence quenching, which is reversed upon competition with other aminoglycosides. Consequently, the proposed device can serve as an integrated microfluidic platform for the high-throughput screening of high affinity antibiotics for RNA targets.