| 摘要 |
The present invention relates to a method and apparatus for manipulation and/or control of the position of particles by means of fields of force of an electrical nature in electrically conductive solutions. The fields of force can be of (positive or negative) dielectrophoresis, electrophoresis, electrohydrodynamics or electrowetting on dielectric, characterized by a set of points of stable equilibrium for the particles. Each point of equilibrium can trap one or more particles within the attraction basin. Said forces dissipate by the Joule effect an amount of power proportional to the square of the voltages applied, causing in a short time the death of the biological particles contained in the specimen. According to the present invention, the dissipated power can be removed through at least one of the substrates in order to maintain the temperature in the liquid suspension constant or reduce it during the entire step of application of the forces. According to the present invention, the amount of heat to be extracted can be controlled by means of a temperature sensor internal to the microchamber or external thereto, which supplies information on the temperature of the system in order to establish a feedback control on the heat pump. In a second embodiment of the method, a flow constantly replaces the buffer, transporting by convection the heat outside the microchamber. Forming the subject of the present invention is likewise a method for minimizing the dissipated power given the same levels of performance by dividing the forces into classes, falling within one of which classes are the forces used for controlling particles in a static way whilst falling within a further class are the forces necessary for displacement of the particles. This can occur in a practical way by increasing the number of potentials that supply the electrodes of the device or else by appropriately modulating the amplitudes of the applied phases or by means of a timed management of the phases. Forming the subject of the present invention are likewise some practical implementations of the method that leads to an apparatus for manipulation of particles in conductive solutions. Said apparatus requires the use of a heat pump, which can be obtained by means of a Peltier-effect device or by means of the convective transport of the flow of heat absorbed by the substrate. Said convective flow uses a liquid or a gas. Forming the subject of the present invention is likewise an apparatus that exploits the gas law for reducing the temperature by varying the pressure of the gas having the function of performing the convective transport or by means of a change of phase from vapour to liquid or vice versa.
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