To concentrate a material by separating it from a diluting medium, the combination of the material and medium is placed in one of two wells in the bottom of a plastic sample concentrator cell, with each well being closed at its bottom end by a different cellophane membrane in contact with a buffer solution in a different one of two buffer compartments. A buffer solution also connects the combination of material and medium in one well and the cellophane bottom of the other well within the sample concentration cell through a recess in the bottom of the sample concentration cell. A potential is applied across the two buffer compartments to cause the material to migrate by electrophoresis from the medium in one well, through the buffer in the sample concentrating cell and into the other well, where it is concentrated against the cellophane membrane for easy removal by pipetting.
This invention provides methods of increasing the frequency of contact between vectors and stationary target cells in an apparatus containing them which involves causing the vectors to move towards the target cells with motion above and beyond random Brownian motion. The methods of this invention include causing the vectors to move in the direction of the cells by (1) causing flow-through of a liquid containing the vectors through or past a cell bed, (2) moving charged vectors towards the target cells by electrodiffusion and (3) centrifuging vectors and cells to cause settling of vectors onto the cells.
This invention provides methods, compositions and apparatus for increasing the transfection efficiency of target cells by particles, especially retroviral particles, compared with that achieved by current methods. The transfection method comprises depositing the particles on a cell growth support and contacting target cells with the particle-loaded cell growth support.
This invention provides methods of increasing the frequency of contact between vectors and stationary target cells in an apparatus containing them which involves causing the vectors to move towards the target cells with motion above and beyond random Brownian motion. The methods of this invention include causing the vectors to move in the direction of the cells by (1) causing flow-through of a liquid containing the vectors through or past a cell bed, (2) moving charged vectors towards the target cells by electrodiffusion and (3) centrifuging vectors and cells to cause settling of vectors onto the cells.
An electrophoresis running tank assembly includes a running tank and a power supply holder that is integral to the running tank. A lid is configured for covering the tank, with two activation arms depending downwardly from the lid and with peripheral vertical skirts of the lid overlapping the walls of the tank. Two switches are held by a switch assembly in the power supply holder and are accessible through a space between the power supply holder and a pin wall that supports two connector pins. When the lid is engaged with the tank, the activation arms extend into the space to abut and thereby close the switches, thereby electrically connecting the switches to the electrode. A power supply can be engaged with the pins to energize the electrodes. Owing to the cooperation between the skirts and the walls of the tank, the lid cannot be tilted relative to the tank to expose the electrodes, but instead must deliberately be lifted up and away from the tank (thus opening the switches and deenergizing the electrodes) to expose the electrodes.
A stable, unchanging concentration gradient of macro-ions dissolved in aqueous or other polar solvents is established adjacent to a semipermeable membrane by the opposing forces of a directed electric field and diffusion, a condition herein defined as electrophoretic steady state. An analysis of the concentration gradient as recorded by an interrogating optical system can yield one or more physical-chemical properties of the macro-ions.
