Chemistry: analytical and immunological testing – Including sample preparation – Volumetric liquid transfer
Reexamination Certificate
2001-01-23
2004-08-17
Warden, Jill (Department: 1743)
Chemistry: analytical and immunological testing
Including sample preparation
Volumetric liquid transfer
C310S31300R, C422S073000, C422S082000, C422S105000, C422S105000, C422S110000
Reexamination Certificate
active
06777245
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a device and a process for directed and specific manipulation of small quantities of matter on the surface of a solid body and use thereof.
2. Description of the Related Art
Movement of small quantities of matter is performed at this point in time primarily in the field of liquids (microfluids). Thus movement of small quantities of liquids (and at the same time suspended particles contained in them, such as biological cells) on a chip has already been used in biology (Anne Y. Fu et al.,
Nature Biotechnology
17 (1999), pages 1109f). To move small quantities of matter, conventional pump systems (including miniaturized pumps) are used on the one hand, that move defined quantities of liquids along defined channels by structuring solid-body surfaces. These conventional pump systems are based essentially on miniaturization of known functional units, which are driven by purely mechanical or piezoelectric actuators. In this, methods of micromechanics are used, among others, based on significant miniaturization of known pump mechanisms or known hydraulic and hydrodynamic functional blocks, such as valves, turbines, nozzles, etc. Another type of liquid transport that has arisen recently is based on utilization of electrokinetic processes, in which an electric field causes movement of a liquid along a defined channel (O. Müller, Laborwelt 1/2000, pages 26 though 38). Movement of small liquid quantities by impulse transfer of a longitudinal volume sound wave on a liquid is known from U.S. Pat. No. 5,674,742 and from U.S. Pat. No. 6,010,316.
In electroosmotic processes, the speed of the quantities of matter to be moved depends on the channel width, as a rule. In addition, the channel must be completely filled, in principle. Also, high field strengths are required to transport small quantities of liquid, which lead, in addition to undesired electrochemical and electrobiological effects, also to an unavoidable joule heating of the quantities of matter to be moved, which can, among other things, affect the functionality of the carrier material.
SUMMARY OF THE INVENTION
The task of the present invention is to provide a device and a process, with the help of which specific manipulation and movement of the smallest quantities of matter on and along the surface of a solid body, in which the movement of the smallest quantities of matter is possible without moving parts and makes cost-favorable and simple production and use possible.
This task is accomplished by a process and device for specific and direct manipulation of small quantities of matter on solid-body surfaces in which, with the aid of one or more acoustic surface waves, an impulse is generated along the solid-body surface, with the surface wave being generated with a surface-wave generator. The impulse is made to interact with at least one quantity of matter in order to cause movement on the surface in a desired direction.
In the process according to the invention, surface waves are generated with the aid of at least one surface-wave generating device, the impulse of which is made to interact with at least one quantity of matter, in order to cause movement in a desired direction. The device according to the invention also has at least one device for generating surface waves on a solid-body surface in at least one direction of spreading and an interaction region, in which the quantity of matter can interact with the at least one surface wave, in order to cause movement of the quantity of matter through an impulse transfer by the surface wave or surface waves.
With the process according to the invention and the device according to the invention, the smallest quantities of matter on the surface of a solid body can be moved or manipulated specifically by means of acoustic surface waves. Here, the concept “matter” includes gases, liquids, and solid substances, but also biological systems, such as cells, macromolecules, and genetic material, as well as small particles, such as chemical reagents or mixtures, solutions, or dispersions of these substances. At least one acoustic surface wave is generated on the surface of the solid body. Through the interaction of small particles, liquids, or gases with the periodic mechanical deformation of the surface, or also through interaction with the electric fields accompanying the wave, these particles, liquids, or gases are moved specifically. Here, the amount and direction of each speed can be set in advance externally. Transport of the matter on the surface of the solid body along a path that can be selected freely and set specifically is thus caused by an impulse transfer between an acoustic surface wave and the small quantity of matter to be transported. Manipulation or movement of the small quantities of matter on the surface of the solid body takes place without direct contact between the actual “pump” and the matter to be transported, since the displacement of the matter is caused by the impulse transfer alone, which occurs, e.g., through mechanical deformation of the solid-body surface or also through electric forces, transmitted through the piezoelectric fields accompanying the surface wave. In addition, at at least one point on the solid-body surface, a corresponding sound converter or a surface-wave generator is prepared, through which a high-frequency acoustic surface wave can be excited along the surface of the solid body.
Matter transport through impulse transfer from a surface wave permits high current and process speeds with comparatively small electric field strengths up to the speed of sound for surface waves on the corresponding substrate. Moreover, the process presented can be scaled over broad ranges, since the speed of the quantity of matter to be moved does not depend on the channel width, as it does, e.g., in the electroosmotic process. In contrast to, e.g., the electroosmotic transport process, no high field strengths are needed for transport that could possibly lead to undesired electrophysical or electrochemical reactions. The small quantities of matter to be transported are located, disregarding any high-frequency alternating field that may be present accompanying the surface wave, in a field-free space. Especially for biological systems, such as cells, damaging effects of high electric fields are thus avoided. The method of functioning of the pump mechanism is independent of the type and properties of a transport or buffer liquid that may be used. In addition, with the process according to the invention, undesired joule heating is avoided.
Since both the direction of the effectively acting surface wave or surface waves on the solid-body surface, as well as their position and amplitude can be set as desired and separately, it is possible to set the transport speed specifically with respect to amount and direction. Thus it is possible to define complex transport segments and paths for small quantities of matter on the solid-body surface.
The surface wave can be generated either continuously or in pulse form.
Finally, it is not necessary, e.g. with closed fluid volumes, to irradiate the entire volume with the surface wave, since because of the incompressibility of liquids, driving a small partial volume is sufficient to move the entire volume.
Another advantage of the device according to the invention is the possibility of moving individual drops, e.g. of a liquid or a buffer solution, forward. Because of surface tension, drops of this kind do not run away from each other. Small quantities of matter can thus be transported without a surrounding column of liquid.
Finally, the process according to the invention and the device according to the invention makes a very directed control of the movement mechanism possible. The surface waves runs laterally, because of the crystal properties of the substrate, * to their being generated on the surface only slightly apart from each other. In this way, a very definite effect of the surface wave on the small quantity of matter is possible, even when the direction
Advalytix AG
Jacobson & Holman PLLC
Siefke Sam P.
Warden Jill
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