Design, Fabrication, and Testing of a Microfluidic Device for Thermotaxis and Chemotaxis Assays of Sperm.

Infertile couples needing assisted reproduction are increasing, so a fundamental understanding of motile sperm migration is required. This paper presents an advanced microfluidic device for sperm motion analysis utilizing chemotaxis and thermotaxis simultaneously for the first time. The proposed device is a transparent polydimethylsiloxane- and glass-based microfluidic chip system providing a low-cost, useful, and disposable platform for sperm analysis.

Disposable on-chip microfluidic system for buccal cell lysis, DNA purification, and polymerase chain reaction.

This paper reports the development of a disposable, integrated biochip for DNA sample preparation and PCR. The hybrid biochip (25 × 45 mm) is composed of a disposable PDMS layer with a microchannel chamber and reusable glass substrate integrated with a microheater and thermal microsensor. Lysis, purification, and PCR can be performed sequentially on this microfluidic device.

Tuning solid-state fluorescence to the near-infrared: a combinatorial approach to discovering molecular nanoprobes for biomedical imaging.

Dyes showing solid-state fluorescence (SSF) are intriguing molecules that can emit bright fluorescence in the condensed phase. Because they do not suffer from self-quenching of fluorescence, nanoscopic dense integration of those molecules produces particulate nanoprobes whose emission intensity can be boosted by raising the intraparticle dye density. In spite of the potential promise for imaging applications demanding intense emission signals, their excitation and emission spectra are generally limited to the visible region where biological tissues have less transparency.

Potential application of antibody-mimicking peptides identified by phage display in immuno-magnetic separation of an antigen.

Phage display was performed against human IgG (hIgG) through five rounds of 'biopanning'. Each round consisted of: (1) incubating a library of phage-displayed 12-mer peptides sequences on hIgG-coated magnetic beads, (2) washing the unbound phages, and (3) eluting the bound phages. The eluted phages were either amplified to enrich the pool of positive clones or subjected to the next round without amplification.

Separation of progressive motile sperm from mouse semen using on-chip chemotaxis.

We present a novel method for the separation of progressive motile sperm from non-progressive motile and immotile sperm. This separation was accomplished by inducing chemotaxis along a longitudinal chemical gradient in a microchip composed of a biocompatible polydimethysiloxane layer and a glass substrate. In a preliminary experiment using fluorescent rhodamine B as a marker, we verified that a chemical gradient was generated by diffusion within the microchannel.

Microchip-based multiplex electro-immunosensing system for the detection of cancer biomarkers.

Microfluidic-based microchips have become the focus of research interest for immunoassays and biomarker diagnostics. This is due to their aptitude for high-throughput processing, small sample volume, and short analysis times. In this paper, we describe the development of a microchip-based multiplex electro-immunosensing system for simultaneous detection of cancer biomarkers using gold nanoparticles and silver enhancer.

A novel microfluidic biosensor based on an electrical detection system for alpha-fetoprotein.

Conventional immunoassays are labor intensive, expensive and time consuming and require large pieces of equipment for detection. Therefore, we have developed and characterized a novel immunoassay methodology comprised of microbeads and microbiochips. In this method, microbeads are used to filter and immobilize antibodies and an immuno-gold silver staining (IGSS) method is then used to amplify electrical signals that correspond to the bound antibodies.