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Chunxiong Luo

Publications and source records attributed to Chunxiong Luo.

5 recordsLinked to original sources
PubMed2006

Picoliter-volume aqueous droplets in oil: electrochemical detection and yeast cell electroporation.

An electrochemical detection method was introduced for aqueous droplet analysis in oil phase of microfluidic devices. This method is based on the electrochemical signal difference between aqueous and oil. Applying a low alternating current (AC) voltage to a couple of Au microelectrodes, this method can offer size information and ion concentration range from 0.02 mmol/L to 1 mol/L of tens of picoliter to nanoliter aqueous droplets. Alternatively, applying a relative high AC voltage (18 Vpp) at a frequency of 1 kHz leads to electroporation of yeast cells encapsulated into picoliter droplets. We believe that this simple technique is useful for a number of aqueous droplet-based chemical and biological analyses as well as cell electroporation.

Electrochemistry↗
PubMed2005

PDMS microfludic device for optical detection of protein immunoassay using gold nanoparticles.

A simple but highly specific immunoassay system for goat anti-human IgG has been developed using gold nanoparticles and microfluidic techniques. The assay is based on the deposition of gold nanoparticles that are coated with protein antigens in the presence of their corresponding antibodies to microfluidic channel surface. The effects of time accumulation, the flow velocity, and the concentration of antibodies to the red light absorption percentage (RAP) of deposition were investigated with an ordinary optical microscope. By controlling the reaction time and flow velocity, a dynamic range of 3 orders of magnitude and a detection sensitivity of 10 ng ml(-1) of goat anti-human IgG were achieved. Because of its simplicity and flexibility, this new technique should be useful for fast, highthroughput screening of antibodies in clinical diagnostic applications.

Animals↗
PubMed2004

Reversibly switchable DNA nanocompartment on surfaces.

Biological macromolecules have been used to fabricate many nanostructures, biodevices and biomimetics because of their physical and chemical properties. But dynamic nanostructure and biomachinery that depend on collective behavior of biomolecules have not been demonstrated. Here, we report the design of DNA nanocompartments on surfaces that exhibit reversible changes in molecular mechanical properties. Such molecular nanocompartments are used to encage molecules, switched by the collective effect of Watson-Crick base-pairing interactions. This effect is used to perform molecular recognition. Furthermore, we found that 'fuel' strands with single-base variation cannot afford an efficient closing of nanocompartments, which allows highly sensitive label-free DNA array detection. Our results suggest that DNA nanocompartments can be used as building blocks for complex biomaterials because its core functions are independent of substrates and mediators.

Base Pair Mismatch↗
PubMed2003

Studies of temperature-dependent electronic transduction on DNA hairpin loop sensor.

A self-assembly monolayer (SAM) of hairpin DNA can be formed on a gold substrate in order to make special biosensors. Labeling the hairpin loop probes with electroactive compositions rather than a fluorophore illustrates interesting profiles of redox current versus temperature. For a biosensor interacting with perfectly complementary targets, the profile shows a characteristic plateau, which disappears when the targets have a single base variation. The plateau is split into multiple steps by tuning the hybridization temperature. We propose that the phenomena are due to hairpin loop compartmentalization. The novel characteristics lead to a thermal gradient detection method that permits perfect discrimination of a target sequence from single nucleotide mismatches.

Base Sequence↗