Abstract: A method is provided for measuring a response to a stimulus of a plurality of samples spots of a sample using a measuring system having a measurement range to generate an image of the sample in digital space. The method includes, for each sample, while measuring the response, varying the stimulus to include at least one stimulus value where the measured response corresponds to a value in an intermediate portion of the measuring range, and storing a value of the measured response that corresponds to a value in the intermediate portion of the measurement range, and the stimulus value that produced that value of the measured response.

Abstract: A method is provided for measuring a response to a stimulus of a plurality of samples spots of a sample using a measuring system having a measurement range to generate an image of the sample in digital space. The method includes, for each sample, while measuring the response, varying the stimulus to include at least one stimulus value where the measured response corresponds to a value in an intermediate portion of the measuring range, and storing a value of the measured response that corresponds to a value in the intermediate portion of the measurement range, and the stimulus value that produced that value of the measured response.

Abstract: Electroporation on a plurality of samples of membranous structures is performed in an electroporation well plate that includes a frame that can hold a plurality of well strips to form a two-dimensional array of wells, and a set of well strips, the set containing strips that differ in the number of wells while having the same outer dimensions and hence being interchangeable, thereby allowing the user to select strips appropriate for a given electroporation procedure, and allowing the manufacturer to replace defective strips without rejecting an entire well plate when a small number of wells is found to be defective.

Abstract: A chamber that includes electrical contacts and a protective lid with a manually operated release is designed to receive a multi-well electroporation plate and to allow high-throughput electroporation on the well contents with minimal risk of electrical shock to the user and minimal opportunity for sample loss and contamination.

Abstract: Biological cells and other membranous structures are transfected in a flow-through system by using a moving charge pattern on a longitudinal wall of a channel to cause the cells to travel through the channel due to an electrostatic interaction between the cells and the moving charge pattern. As the cells travel through the channel, they pass a transmitter that emits transfection energy sufficient to make the cell membranes permeable such that exogenous species in the fluid in which the cells are suspended will enter the cell interiors.

Abstract: An electroporation cuvette is constructed as a cylinder with a filament electrode at the cylinder axis and one or more peripheral electrodes on the internal cylinder wall. An additional cuvette design is one with a plurality of peripheral electrodes distributed at various locations around the circumference of the cuvette wall and no central electrode. The various arrangements of electrodes lead to electric field vectors that are non-uniform and of varying orientation, producing high field intensities and agitation of the cell suspension in the cuvette during electroporation.

Abstract: Systems and methods of measuring resistances of samples to be electroporated and utilizing the measured resistances in the electroporation are provided. During an electrical pulse sent to the sample, a time and a corresponding voltage drop on a known capacitance is measured to determine the sample resistance. A constant voltage may be assumed, and the voltage drop across a known resistance in series with the sample resistance is used to determine the sample resistance. Based on the value of the sample resistance, an electrical pulse may be altered by changing a value of a parallel resistance.

Abstract: Systems, methods and apparatus for stabilizing resistance measurements in electroporation systems so as to achieve high-accuracy measurements, and for controlling the pulse duration, or time constant, of electroporation pulses. Circuitry is provided to accurately determine the resistance of a sample in the electroporation system, for example a sample provided in an electroporation cuvette. Additionally, a resistance control system is provided to automatically measure the resistance of a sample, determine a capacitance and determine a parallel add-on resistance that substantially provides a desired pulse duration (time constant) for an electroporation pulse.

Abstract: Cuvette inserts adapted and configured to fit within an electroporation cuvette. The inserts each include a support structure that holds a porous membrane. When positioned within the cuvette, the membrane is positioned proximal the cuvette electrodes to facilitate membrane-based fusion of cells. In certain aspects, a tube extends through the support structure to allow for application of negative pressure in a convenient location away from electrode contacts and other components of the cuvette or cuvette holder.

Abstract: Systems, methods and apparatus for stabilizing resistance measurements in electroporation systems so as to achieve high-accuracy measurements, and for controlling the pulse duration, or time constant, of electroporation pulses. Circuitry is provided to accurately determine the resistance of a sample in the electroporation system, for example a sample provided in an electroporation cuvette. Additionally, a resistance control system is provided to automatically measure the resistance of a sample, determine a capacitance and determine a parallel add-on resistance that substantially provides a desired pulse duration (time constant) for an electroporation pulse.

Abstract: Systems, methods and algorithms for automatically performing optimization of an electroporation system. A system according to the present invention typically includes a cuvette holding assembly configured to hold a plurality of electroporation cuvettes, wherein each cuvette includes a first and second electrode, and a shocking chamber configured to hold the cuvette holding assembly, the chamber having a commutator assembly configured to provide an electrical contact to the first electrode of each of the plurality of cuvettes in turn. The system also typically includes a control system communicably coupled to the shocking chamber, wherein the control system controls the commutator to automatically contact the first electrode of each cuvette in an order and to provide a potential across the cuvette electrodes when contact is made.

Abstract: Cuvette inserts adapted and configured to fit within an electroporation cuvette. The inserts each include a support structure that holds a porous membrane. When positioned within the cuvette, the membrane is positioned proximal the cuvette electrodes to facilitate membrane-based fusion of cells. In certain aspects, a tube extends through the support structure to allow for application of negative pressure in a convenient location away from electrode contacts and other components of the cuvette or cuvette holder.

Abstract: An electroporation system and method for directing high-voltage currents to a suspension of cells contained in a cuvette. A high-voltage switch controls the coupling of a charge control to a high-voltage capacitor and, additionally, controls the coupling of the high-voltage capacitor to the cuvette. A current diverter diverts current away from the sample whenever an arc condition commences or a low sample resistance is detected across the cuvette. The current diverter includes a current diverter switch, which is triggered when a sense resistor measures a second predetermined voltage indicative of an arc-over event (or a low sample resistance condition).

Abstract: The present invention provides apparatus and method for simply and efficiently improving prior art transfection systems. The present invention is a transfection high-voltage controller that provides features for measuring actual load resistance, and compensating for any effects of a limit impedance in series with the load. Additionally, the transfection controller of the present invention measures actual effective capacitance of a storage capacitor, or capacitors, and through use of an expansion module, effectively provides the user with a set of user-selectable capacitors having an effective .+-.10% tolerance when the tolerance of the individual electrolytic capacitors is .+-.20%. The preferred embodiment incorporates two sections. One section of the system handles 200-2500V and another section handles low voltages (50-500V).

Abstract: The present invention provides apparatus and method for simply and efficiently improving prior art transfection systems. The present invention is a transfection high-voltage controller that provides features for measuring actual load resistance, and compensating for any effects of a limit impedance in series with the load. Additionally, the transfection controller of the present invention measures actual effective capacitance of a storage capacitor, or capacitors, and through use of an expansion module, effectively provides the user with a set of user-selectable capacitors having an effective .+-.10% tolerance when the tolerance of the individual electrolytic capacitors is .+-.20%. The preferred embodiment incorporates two sections. One section of the system handles 200-2500 V and another section handles low voltages (50-500 V).

Abstract: The present invention provides apparatus and method for simply and efficiently improving prior art transfection systems. The present invention is a transfection high-voltage controller that provides features for measuring actual load resistance, and compensating for any effects of a limit impedance in series with the load. Additionally, the transfection controller of the present invention measures actual effective capacitance of a storage capacitor, or capacitors, and through use of an expansion module, effectively provides the user with a set of user-selectable capacitors having an effective .+-.10% tolerance when the tolerance of the individual electrolytic capacitors is .+-.20%. The preferred embodiment incorporates two sections. One section of the system handles 200-2500 V and another section handles low voltages (50-500 V).

Abstract: An arc detector for detecting electrical arcs across a break in a line carrying a current in an electrical system. Normally, the line carries current, but when the line is broken, current doesn't flow until an arc occurs across the break. The arc detector detects the break using a current sensor for measuring the current, a filter for filtering out unwanted frequencies, an amplifier for amplifying the remaining frequencies into a substantially square wave, a counter for counting square wave transitions, and a latch to hold a detection signal at an output node when the counter counts a preset number of square wave transitions without being reset by a reset switch or a periodic oscillator.

Abstract: A buffer solution being used in an electrophoresis cell as both an electrode buffer and a cooling medium is circulated through a refrigeration system external to the cell without risk of arcing or other danger despite the electrified state of the buffer solution. The refrigeration system contains a circulating coolant, a shell-and-tube heat exchanger, various components for the coolant such as a compressor, condenser and capillary, and preferably also a by-pass which, on command from a temperature control unit, passes warm coolant from the compressor discharge directly to the heat exchanger. Couplings of dielectric material insulate the heat exchanger from the remaining components of the refrigeration system.

Abstract: A contour-clamped homogeneous electric field generator having a plurality of electrodes, each electrode being connected to a node which is maintained at a prescribed electrical potential. The electrical potential at the node is maintained by sourcing current into or sinking current away from the node when the voltage at the node varies. The current source comprises a first transistor having an input terminal connected to a voltage/current supply and an output terminal connected to the node. The current sink comprises a second transistor having an input terminal coupled to the node, and an output terminal coupled to the voltage/current supply ground. To control the operation of the first and second transistors, a comparator is coupled to the node for comparing a node-derived voltage to a reference voltage and for providing an oscillating pulse train in response thereto. The duty cycle of the pulse train varies in response to node voltage variation.

Abstract: A transfection high-voltage controller for directing high-voltage currents to a suspension of cells and DNA comprising a control section, a power store, and a high-joule switch. Under control of the control section, the high-joule switch directs a high-voltage current from the power store to a load such as a cuvette. The high-joule switch comprises a semiconductor controlled rectifier (SCR) having a gate coupled to the control unit for triggering the device, an anode for receiving the high-voltage current from the power store, and a cathode for delivering the high-voltage current to the cuvette. A current sink may be connected to the anode of the SCR to render it non-conductive a predetermined time after the high-voltage current appears at the cathode. Multiple SCRs may be connected in series to support voltages over 3,000 and currents in excess of 125 amperes, and a trigger control unit may be attached to the gate of each SCR in the series to effect simultaneous or serial triggering of the group.