Micro fluidic structures

Abstract

A micro fluidic system includes a substrate, and, provided on said substrate, at least one flow path interconnecting with functional means in which liquid samples can be treated by desired procedures. The flow paths are laid out to form a pattern for the transport of liquid samples to and from said functional means. These flow paths comprise a plurality of micro posts protruding upwards from said substrate, the spacing between the micro posts being small enough to induce a capillary action in a liquid sample applied anywhere within any of said flow paths, so as to force said liquid to move from where said liquid sample was applied.

1 - 20 . (canceled) 
     
     
         21 . A micro fluidic system, said system comprising:
 a substrate having a non-porous surface;   a plurality of microposts protruding from the non-porous surface of said substrate, said microposts defining at least one open flow path in which liquid samples can be treated by desired procedures, wherein said at least one flow path is laid out for transport of liquid samples, the at least one flow path extending in a lateral direction which is transverse to the protruding microposts, wherein cross sections of said microposts and the center to center spacing between each of the microposts spontaneously induces a passive capillary action in a liquid sample applied to said at least one flow path, so as to force said liquid to move laterally away from where said liquid sample was applied, said microposts further including at least one biological or chemical binder having an affinity to at least one component of a liquid sample introduced along said at least one flow path;   a sample receiving area disposed prior to said at least one flow path and fluidly connected therewith; and   a sample collecting sink disposed after said at least one flow path on said substrate and fluidly connected with said at least one flow path, said sample collecting sink having an area which is larger than the area of the at least one flow path extending from said sample receiving area, said sink having a plurality of microposts protruding from said substrate surface, said sink microposts having cross sections and center to center spacing between each of said microposts that further induce capillary flow from said at least one flow path to said sample collecting sink.   
     
     
         22 . The micro fluidic system according to  claim 21 , wherein said substrate is provided with grooves having a bottom surface and side walls, said plurality of microposts defining said at least one fluid path protruding from a bottom surface of said grooves and wherein the passive capillary action is caused essentially between said liquid and the microposts. 
     
     
         23 . The micro fluidic system according to  claim 22 , wherein said plurality of microposts defining said at least one flow path has a height dimension, said at least one flow path being covered by a lid, said lid being positioned at a distance from the surface of the substrate to the lid that is considerably larger than the height dimension of said plurality of microposts defining said at least one fluid path such that no capillary action between the substrate and the lid can arise. 
     
     
         24 . The micro fluidic system according to  claim 23 , wherein the lid has access openings for enabling introduction of at least one of reagents, gas, liquids, and samples into said at least one flow path. 
     
     
         25 . The micro fluidic system of  claim 21 , wherein said substrate is substantially flat, the plurality of microposts defining said at least one flow path being grouped in adjacent segments so as to provide a capillary barrier discontinuity between such segments, the capillary barrier discontinuity having a finite distance, preventing the capillary flow between said segments, thereby providing a flow stop. 
     
     
         26 . The micro fluidic system according to  claim 25 , further comprising means for applying energy to one or more selected segments to induce a forced transport across the flow stop. 
     
     
         27 . The micro fluidic system according to  claim 26 , wherein said means for applying energy is selected from at least one of a pressure pulse generator, an ultrasound generator, and an electromagnetic radiation means. 
     
     
         28 . The micro fluidic system according to  claim 25 , further comprising means for applying liquid to said capillary barrier discontinuity to provide a bridge across said discontinuity so as to induce a flow there across. 
     
     
         29 . The micro fluidic system according to  claim 21 , wherein surfaces of the microposts defining at least one flow path have at least one of a chemical, biologic or physical functionality applied to said plurality of microposts in the entire at least one flow path or limited to a portion thereof. 
     
     
         30 . The micro fluidic system according to  claim 29 , wherein said microposts defining said at least one flow path have at least one of chemically reactive and hydrophilic groups on their surfaces. 
     
     
         31 . The micro fluidic system according to  claim 29 , wherein the plurality of microposts defining said at least one flow path have positively and/or negatively charged groups on their surfaces. 
     
     
         32 . The micro fluidic system according to  claim 29 , wherein the plurality of microposts defining said at least one flow path have hydrophobic structures on their surfaces. 
     
     
         33 . The micro fluidic system according to  claim 29 , wherein said plurality of microposts defining said at least flow path have a property that is selected from the group consisting of a diameter of 20 μm, a height of 100 μm, a square shape, a circular cross section, a hydrophobic surface coating, a hydrophilic surface coating, and a micropost spacing distance from center-to center of 30 μm. 
     
     
         34 . The micro fluidic system according to  claim 21 , wherein particles are provided within said at least one flow path. 
     
     
         35 . The micro fluidic system according to  claim 34 , wherein said particles are chemically or physically bound to the substrate, or mechanically trapped within a region comprising at least a portion of said plurality of microposts defining said at least one flow path. 
     
     
         36 . The micro fluidic system according to  claim 21 , wherein said at least one flow path has integrated zones or delimited surfaces containing at least one of means for electrical manipulation of liquids and/or reagents, means for transmitting, focusing, reflecting or absorbing light and means for the regulation of the temperature in said zone. 
     
     
         37 . The micro fluidic system according to  claim 21 , wherein said plurality of microposts defining said at least one flow path are defined by an aspect ratio of at least 1:2. 
     
     
         38 . The micro fluidic system according to  claim 21 , wherein said plurality of microposts defining said at least one flow path are defined by an aspect ratio of at least 1:5. 
     
     
         39 . The structure according to  claim 21 , wherein said plurality of micro posts defining said at least one flow path are defined by a diameter of approximately 20 micrometers, a height of approximately 100 micrometers and a center to center distance between adjacent microposts of approximately 30 micrometers. 
     
     
         40 . A micro fluidic system, said system comprising:
 a substrate having a non-porous surface;   a first plurality of microposts protruding from said non-porous surface of said substrate and defining at least one open flow path in which liquid samples can be treated by desired procedures, wherein said at least one flow path is laid out for transport of liquid samples, wherein the at least one flow path extends in a lateral direction which is transverse to the protruding microposts; wherein cross sections of said microposts and the center to center spacing between each of the first plurality of microposts spontaneously induces a passive capillary action in a liquid sample applied to said at least one flow path, so as to force said liquid to move laterally away from where said liquid sample was applied, said first plurality of microposts further including at least one biological binder having an affinity to at least one component of a liquid sample introduced along said at least one flow path;   a sample receiving area disposed prior to said at least one flow path and fluidly connected therewith; and   a sample collecting sink disposed after said at least one flow path on said substrate and fluidly connected with said at least one flow path, said sample collecting sink having an area which is larger than the area of the at least one flow path extending from said sample receiving area, said sink having a second plurality of microposts protruding from said substrate surface, said second plurality of microposts having cross sections and center to center spacing between each of said microposts that further induce capillary flow from said flow path to said sample collecting sink.