We present a rapidly fabricated micro-capillary electrophoresis chip that utilizes surface-tension-driven flow for sample injection and extraction of DNA. Surface-tension-driven flow (i.e. passive pumping) [G. M. Walker et al., Lab. Chip. 2002, 2, 131-134] injects a fixed volume of sample that can be predicted mathematically. Passive pumping eliminates the need for tubing, valves, syringe pumps...

Small retinal detachments (blebs) were made in living eyes by injecting balanced salt solution into the subretinal space with a micropipette. A second micropipette, inserted into the same bleb, measured subretinal pressure using a resistance servonulling system. The adhesive force was calculated from the pressure difference across the retina according to Laplace's law. The retinal adhesive forc...

The red cell's spectrin-actin network is known to sustain local states of shear, dilation, and condensation, and yet the short actin filaments are found to maintain membrane-tangent and near-random azimuthal orientations. When calibrated with polarization results for single actin filaments, imaging of micropipette-deformed red cell ghosts has allowed an assessment of actin orientations and poss...

We report a highly efficient, simple, and non-infective method for labeling individual long-range projection neurons (LRPNs) in a specific location with enough sparseness and intensity to allow complete and unambiguous reconstructions of their entire axonal tree. The method is based on the "in vivo" transfection of a large RNA construct that drives the massive expression of green fluorescent pr...

Micropipette aspiration measures the mechanical properties of single cells. A traditional micropipette aspiration system requires a bulky infrastructure and has a low throughput and limited potential for automation. We have developed a simple microfluidic device which is able to trap and apply pressure to single cells in designated aspiration arrays. By changing the volume flow rate using a syr...

The erythrocyte's spectrin-actin membrane skeleton is directly shown to be capable of sustaining large, anisotropic strains. Photobleaching of an approximately 1-micrometer stripe in rhodamine phalloidin-labeled actin appears stable up to at least 37 degrees C, and is used to demonstrate large in-surface stretching during elastic deformation of the skeleton. Principal extension or stretch ratio...

Measuring cellular respiration with single-cell spatial resolution is a significant challenge, even with modern tools and techniques. Here, a double-channel micropipette is proposed and investigated as a probe to achieve this goal by sampling fluid near the point of interest. A finite element model (FEM) of this perfusion probe is validated by comparing simulation results with experimental resu...

The in vivo effects on the retinal adhesive force of injecting metabolically active agents into the subretinal space of rabbits were studied. Small retinal detachments (blebs) were made in living Dutch rabbit eyes by injecting experimental solutions into the subretinal space with a micropipette. A second micropipette, inserted into the same bleb, measured fluid pressure using a resistance servo...