Microfluidics

We present the design, fabrication and results of microfabricated interfaces for the patterned delivery of foreign molecules via electroporation into developing embryos. We show how these systems can be used to ‘draw’ two-dimensional patterns of tracer molecules, DNA and mRNA into the yolk and cells of zebrafish embryos (Danio rerio) at different stages of development. We demonstrate the successful delivery of two-dimensional patterns of trypan blue (normal dye), texas red (fluorescent dye), pCS2eGFP DNA and GFP-mRNA in both chorionated and dechorionated embryos. Both DNA and...

Dielectrophoresis (DEP) is the translation of tiny particles, nanometer to micrometer scale, resulting from non-uniform electric fields. Particle motion is dictated by the complex permittivity of the particle, the complex permittivity of the carrier solution (e.g. aqueous buffer), and the local electric field gradient. DEP is an attractive microfluidic manipulation technique because electric fields can be used to exert forces on uncharged particles or biological organisms. DEP has been used in applications ranging from particle separation to bacteria characterization. Here we propose...

Nearly all medical implants and tissue engineered structures (i.e. lab-grown organs) are implanted or grown in a manner where it is difficult to non-destructively assess performance or progress and to make adjustments on the fly. For instance, suppose we wish to engineer a vascular graft to repair a damaged coronary blood vessel. In this case, we would start by taking a scaffold material shaped like a blood vessel and then coating it with endothelial and smooth muscle cells. We would then 'grow' the structure in a bioreactor for a fixed period of time and then implant it into the...

Adult Somatic cells, such as skin cells, from patients can be used to derive induced pluripotent stem cells (iPS) by transduction of four Yamanaka transcription factors. Those patient specific iPS cells, with similar properties to embryonic stem (ES) cells, show great potential on various applications, such as drug screening and disease modeling. However, in applying this technique to therapeutic applications such as tissues regeneration, progress is often hampered by low efficiency (about 0.01 to 0.1%) and slow reprogramming (few weeks). Here, we present a novel way to overcome this...