Abstract:
Vented ceramic tips are disclosed which have increased durability and precision for use in microarray technology. As such, vented ceramic tip arrangements for use with a microarray are presented including: a ceramic wall disposed about an axis, the ceramic wall defining an irregular cavity along the axis, the ceramic wall including an attachment end and a tip end; an attachment portion disposed proximal to the attachment end; the attachment portion configured to receive a matching shaft; a tip portion disposed proximal to the tip end; the tip portion configured to receive and deliver a fluidic medium; a vent portion centrally disposed along the ceramic wall; the vent portion having at least one vent, the at least one vent disposed substantially perpendicular to the first axis.

Description:
BACKGROUND  
       [0001]     Microarray technology developments have enabled the mapping of the human genome in a time span that was impossible only a decade ago. Indeed, the ability to process thousands of laboratory samples simultaneously has made a once tedious and time consuming task obsolete. Not surprisingly, as technology has evolved, new demands utilizing that technology have been created. Forensic DNA testing is one such example that is being widely recognized as an invaluable investigative tool for criminal investigations. These new demands have encouraged technologists to continue their search for advancements in once seemingly unrelated technologies.  
         [0002]     One example of a seemingly unrelated technology is found in microelectronic circuit manufacturing technology. Ceramic tips used in microelectronic applications are typically used for delivering very fine interconnection wires. Interconnection wires, in some examples, may be as small as 25 microns in diameter. The ability to accurately and precisely manipulate these wires have allowed for the design of circuit features in high density, small profile packages. However, because of their unique configuration, ceramic tips used in microelectronic circuit manufacturing have found application in emerging microarray technologies.  
         [0003]     Capillary action describes a phenomenon that occurs when a liquid is drawn into a thin tube. The capillary effect is a function of the ability of the liquid to wet a particular material. Typically, the narrower the tube, the higher the liquid will travel up the tube against others forces such as gravity, for example. Interestingly, ceramic tips used in electronic circuit manufacturing exhibits capillary effects. These effects have not gone unnoticed.  
         [0004]     In “Ceramic Capillaries for Use in Microarray Fabrication,” Reed et al. (Reed) explores alternative uses for ceramic tips generally used in microelectronics. Reed found that ceramic tips improve the consistency of deposit morphology, resist deformation over long-term use, cost less, and offer the potential for significant improvement in deposit density. At least part of the reason the ceramic tips in Reed function is because of their inherent capillary properties. The same fine tube that delivers wires in microelectronics may also deliver fluidic media based on capillary effects.  
         [0005]     However, ceramic tips utilized under Reed&#39;s methods may suffer from clogging in some examples. Thus, the same property that allows for capillary effects (i.e. small tube diameter) may also increase the likelihood of clogging. Further, control of volumetric parameters may be limited to tube diameter thus resulting in limited application. Still further, to prevent vapor lock, Reed utilizes hollow shafts for holding ceramic tips which may be difficult or costly to manufacture. As such, vented ceramic tip arrangements for use with a microarray are presented herein.  
       SUMMARY  
       [0006]     Vented ceramic tips are disclosed which have increased durability and precision for use in microarray technology. As such, vented ceramic tip arrangements for use with a microarray are presented including: a ceramic wall disposed about an axis, the ceramic wall defining an irregular cavity along the axis, the ceramic wall including an attachment end and a tip end; an attachment portion disposed proximal to the attachment end; the attachment portion configured to receive a matching shaft; a tip portion disposed proximal to the tip end; the tip portion configured to receive and deliver a fluidic medium; a vent portion centrally disposed along the ceramic wall; the vent portion having at least one vent, the at least one vent disposed substantially perpendicular to the first axis.  
         [0007]     In other embodiments, microarray fluidic medium delivery systems are presented including: a number of vented ceramic tips for receiving and delivering fluidic media; a number of shafts connected with the vented ceramic tips for securing the ceramic tips; a manifold configured to receive and secure the shafts; a number of fluidic wells for presenting the fluidic media to the vented ceramic tips; and a microarray slide for receiving the fluidic media from the vented ceramic tips. In some embodiments, further embodiments include: a three-axis robotic manipulation system coupled with the manifold for moving the manifold along three axes; and a control system for controlling the robotic manipulation system. In some embodiments, vented ceramic tips include: a ceramic wall disposed about an axis, the ceramic wall defining an irregular cavity along the axis, the ceramic wall including an attachment end and a tip end; an attachment portion disposed proximal to the attachment end; the attachment portion configured to receive a matching shaft; a tip portion disposed proximal to the tip end; the tip portion configured to receive and deliver a fluidic medium; a vent portion centrally disposed along the ceramic wall; the vent portion having at least one vent, the at least one vent disposed substantially perpendicular to the first axis. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:  
         [0009]      FIG. 1  is an illustrative orthogonal representation of a tip/shaft assembly in accordance with an embodiment of the present invention;  
         [0010]      FIGS. 2A-2C  are illustrative cross-sectional representations of vented ceramic tips in accordance with embodiments of the present invention;  
         [0011]      FIGS. 3A-3B  are illustrative representations of vents disposed along a plurality of planes in accordance with embodiments of the present invention; and  
         [0012]      FIGS. 4A-4C  are illustrative representations of vented ceramic tip usage in accordance with embodiments of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0013]     The present invention will now be described in detail with reference to a few embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention.  
         [0014]      FIG. 1  is an illustrative orthogonal representation of a tip/shaft assembly  100  in accordance with an embodiment of the present invention. Assembly  100  comprises a vented ceramic tip  112  and a shaft  102 . Shaft  102  may be composed of any material suitably selected to resist corrosive elements for a particular application. For example, stainless steel may be an appropriate material for shaft  102  in applications utilizing aqueous solutions. Shaft  102  may be configured with holding sleeve  104 . Holding sleeve  104  serves to hold shaft  102  securely in a manifold that is configured to secure any number of shafts in accordance with user preferences. A manifold (not shown) may be coupled with a robotic manipulation system to allow movement of the manifold (and secured assemblies) through three axes. In this manner a number of fluidic wells for presenting fluidic media to an assembly may be accessed. Furthermore, a microarray slide (not shown) may be configured to receive fluidic media from an assembly secured in a manifold. In this manner, many reactions may be accomplished using micro liter volumes of fluidic media on a test site. As can be appreciated, a control system may be utilized to automate robotic manipulations in some embodiments.  
         [0015]     Other manners of securing shaft  102  may be accomplished without departing from the present invention. Thus, shaft  102  may be configured as a straight shaft, a tapered shaft, a splined shaft, a keyed shaft, and a threaded shaft without departing from the present invention. Alignment features such as an eccentric cam (not shown) may be further utilized without departing from the present invention.  
         [0016]     Shaft  102  may also be configured with a shaft attachment point  106 . Shaft attachment point  106  is configured to receive vented ceramic tip  112 . As illustrated, shaft attachment point  106  is configured with a tapered shaft, although any number of configurations may be utilized such as, a straight shaft, a splined shaft, a keyed shaft, and a threaded shaft without departing from the present invention. In some embodiments, shaft  102  may be glued, bonded, or otherwise permanently or removably affixed with vented ceramic tip  112  without departing from the present invention.  
         [0017]     Vented ceramic tip  112  may be configured with an irregular cavity  108  disposed along axis  130 . Vented ceramic tip  112  may also be configured with a vent or vent portion  110 . In some embodiments more than one vent may be utilized. In other embodiments, a channel extending to irregular cavity  108  may be utilized. Vented ceramic tip  112  may also be configured with an attachment portion  116  and a tip portion  114 . Vented ceramic tip  112  embodiments will be discussed in further detail below for  FIGS. 2A-2C . As may be appreciated, illustrative representations are presented to clarify embodiments of the present invention. They are not necessarily to scale and no such limitation should be inferred there from.  
         [0018]      FIGS. 2A-2C  are illustrative cross-sectional representations of vented ceramic tips in accordance with embodiments of the present invention.  FIG. 2A  is an illustrative cross-section of a vented ceramic tip arrangement  200  configured with one vent  208 . A ceramic wall  215  is disposed about axis  218  to form an irregular cavity  214 . Irregular cavity  214  may be formed by molding, drilling, grinding, milling or any other method well-known in the art. In some embodiments, ceramic wall  215  may be coated with a hydrophobic compound. In other embodiments, ceramic wall  215  may be coated with a hydrophilic compound. Selection of a coating compound will depend on fluidic media characteristics.  
         [0019]     Vented ceramic tip arrangement  200  may be configured with at least three functional areas: an attachment portion  202 , a vent portion  204 , and a tip portion  206 . Attachment portion  202  is disposed proximal to attachment end  213  and may be configured to receive a shaft such as shaft  102  (see  FIG. 1 ). In one embodiment, attachment portion  202  may have a diameter of approximately 760 microns. In other embodiments, attachment portion  202  may have a diameter less than or equal to 1000 microns. As noted above, attachment portion  202  may be configured to receive a straight shaft, a tapered shaft, a splined shaft, a keyed shaft, and a threaded shaft without departing from the present invention. In each of the above shaft embodiments, attachment portion  202  may be formed by molding, drilling, grinding, milling or any other method well-known in the art.  
         [0020]     Vent portion  204  may be configured with any number of vents. In the present illustration, vent portion  204  contains one vent  208 . As can be seen, vent  208  is disposed substantially perpendicular to axis  218 . As may be appreciated, vent  208  may be formed by molding, drilling, grinding, milling or any other method well-known in the art without departing from the present invention.  
         [0021]     Tip portion  206  is disposed proximal to tip end  222 . In some embodiments, tip portion  206  tapers to tip end  222 , tip end  222  having a diameter of approximately 28 microns. In other embodiments, tip end  222  has a diameter of approximately 20 to 60 microns. In still other embodiments, tip end  222  has a diameter less than or equal to 760 microns. In still other embodiments, tip end  222  diameter is selected to deliver a spot of fluidic medium having a diameter of approximately 40 to 70 microns. In some embodiments, tip end  222  diameter is selected to deliver a spot of fluidic medium having a diameter of approximately 30 to 200 microns. As can be appreciated, tip end  222  diameter is directly related to spot diameter. As such, any number of tip end diameters may be selected in accordance with user preferences. Finally, in some embodiments, irregular cavity  214  may be configured with a taper as seen by 90° rotated view at  216 . Tapering may be utilized to enhance fluidic release from ceramic wall  215 .  
         [0022]      FIG. 2B  is an illustrative cross-section of a vented ceramic tip arrangement  230  configured with three vents  238 ,  240 , and  242 . A ceramic wall  245  is disposed about axis  248  to form an irregular cavity  244 . Irregular cavity  244  may be formed by molding, drilling, grinding, milling or any other method well-known in the art. In some embodiments, ceramic wall  245  may be coated with a hydrophobic compound. In other embodiments, ceramic wall  245  may be coated with a hydrophilic compound. Selection of a coating compound will depend on fluidic media characteristics.  
         [0023]     Vented ceramic tip arrangement  230  may be configured with at least three functional areas: an attachment portion  232 , a vent portion  234 , and a tip portion  236 . Attachment portion  232  is disposed proximal to attachment end  243  and may be configured to receive a shaft such as shaft  102  (see  FIG. 1 ). In one embodiment, attachment portion  232  may have a diameter of approximately 760 microns. In other embodiments, attachment portion  232  may have a diameter less than or equal to 1000 microns. As noted above, attachment portion  232  may be configured to receive a straight shaft, a tapered shaft, a splined shaft, a keyed shaft, and a threaded shaft without departing from the present invention. In each of the above shaft embodiments, attachment portion  232  may be formed by molding, drilling, grinding, milling or any other method well-known in the art.  
         [0024]     Vent portion  234  may be configured with any number of vents. In the present illustration, vent portion  234  contains three vents  238 ,  240 , and  242 . As can be seen, vents  238 ,  240 , and  242  are disposed substantially perpendicular to axis  218 . As may be appreciated, vents  238 ,  240 , and  242  may be formed by molding, drilling, grinding, milling or any other method well-known in the art without departing from the present invention. Vented ceramic tip arrangement  230  may, in some embodiments, be configured with vent cover  250 . Vent cover  250  allows vents  238 ,  240 , and  242  to be selectively closed such that various volumetric configurations may be readily utilized. Thus, if a lower volumetric configuration is desired, vent cover  250  maybe be disposed to cover vents  238 , and  240 . In that configuration, fluid only rises by capillary effect to the lowest uncovered vent (e.g. vent  242 ). If a higher volumetric configuration is desired, vent cover  250  may be disposed to cover vents  240 , and  242 . In that configuration, fluid rises by capillary effect to the lowest uncovered vent (e.g. vent  238  as illustrated). In some embodiments, vent cover  250  may be permanently affixed with ceramic wall  245 . In other embodiments, vent cover  250  may be removably attached with ceramic wall  245 .  
         [0025]     Tip portion  236  is disposed proximal to tip end  252 . In some embodiments, tip portion  236  tapers to tip end  252 , tip end  252  having a diameter of approximately 28 microns. In other embodiments, tip end  252  has a diameter of approximately 20 to 60 microns. In still other embodiments, tip end  252  has a diameter less than or equal to 760 microns. In still other embodiments, tip end  252  diameter is selected to deliver a spot of fluidic medium having a diameter of approximately 40 to 70 microns. In some embodiments, tip end  252  diameter is selected to deliver a spot of fluidic medium having a diameter of approximately 30 to 200 microns. As can be appreciated, tip end  252  diameter is directly related to spot diameter. As such, any number of tip end diameters may be selected in accordance with user preferences. Finally, in some embodiments, irregular cavity  244  may be configured with a taper as seen by 90° rotated view at  246 . Tapering may be utilized to enhance fluidic release from ceramic wall  245 .  
         [0026]      FIG. 2C  is an illustrative cross-section of a vented ceramic tip arrangement  260  configured with a vent channel  238 . A ceramic wall  275  is disposed about axis  278  to form an irregular cavity  274 . Irregular cavity  274  may be formed by molding, drilling, grinding, milling or any other method well-known in the art. In some embodiments, ceramic wall  275  may be coated with a hydrophobic compound. In other embodiments, ceramic wall  275  may be coated with a hydrophilic compound. Selection of a coating compound will depend on fluidic media characteristics.  
         [0027]     Vented ceramic tip arrangement  260  may be configured with at least three functional areas: an attachment portion  262 , a vent portion  264 , and a tip portion  266 . Attachment portion  262  is disposed proximal to attachment end  273  and may be configured to receive a shaft such as shaft  102  (see  FIG. 1 ). In one embodiment, attachment portion  262  may have a diameter of approximately 760 microns. In other embodiments, attachment portion  262  may have a diameter less than or equal to 1000 microns. As noted above, attachment portion  262  may be configured to receive a straight shaft, a tapered shaft, a splined shaft, a keyed shaft, and a threaded shaft without departing from the present invention. In each of the above shaft embodiments, attachment portion  262  may be formed by molding, drilling, grinding, milling or any other method well-known in the art.  
         [0028]     Vent portion  264  may be configured with any number of vents. In the present illustration, vent portion  264  is configured with vent channel  268 . As can be seen, vent channel  268  is disposed substantially perpendicular to axis  278 . As may be appreciated vent channel  268  may be formed by molding, drilling, grinding, milling or any other method well-known in the art without departing from the present invention. Vented ceramic tip arrangement  260  may, in some embodiments, be configured with vent cover  280 . Vent cover  280  allows vent channel  268  to be selectively covered such that various volumetric configurations may be readily utilized. Thus, if a lower volumetric configuration is desired, vent cover  280  maybe be disposed to uncover a lower portion of vent channel  268 . In that configuration, fluid only rises by capillary effect to the lowest uncovered vent channel portion. If a higher volumetric configuration is desired, vent cover  280  may be disposed to cover a lower portion of vent channel  268 . In that configuration, fluid rises by capillary effect to the lowest uncovered vent channel portion. In some embodiments, vent cover  280  may be permanently affixed with ceramic wall  275 . In other embodiments, vent cover  280  may be removably attached with ceramic wall  275 .  
         [0029]     Tip portion  266  is disposed proximal to tip end  282 . In some embodiments, tip portion  266  tapers to tip end  282 , tip end  282  having a diameter of approximately 28 microns. In other embodiments, tip end  282  has a diameter of approximately 20 to 60 microns. In still other embodiments, tip end  282  has a diameter less than or equal to 760 microns. In still other embodiments, tip end  282  diameter is selected to deliver a spot of fluidic medium having a diameter of approximately 40 to 76 microns. In some embodiments, tip end  282  diameter is selected to deliver a spot of fluidic medium having a diameter of approximately 30 to 200 microns. As can be appreciated, tip end  282  diameter is directly related to spot diameter. As such, any number of tip end diameters may be selected in accordance with user preferences. Finally, in some embodiments, irregular cavity  274  may be configured with a taper as seen by 90° rotated view at  276 . Tapering may be utilized to enhance fluidic release from ceramic wall  275 .  
         [0030]      FIGS. 3A-3B  are illustrative representations of vents disposed along a plurality of planes in accordance with embodiments of the present invention.  FIG. 3A  is an illustrative cross-sectional representation of a vented ceramic tip  300  having a single vent, multiple vents, or a channel  304  disposed along an axis  310  in accordance with embodiments of the present invention. As illustrated, ceramic wall  302  is disposed around an axis formed at the intersection of axes  310  and  312 . Vent(s) or channel  304  may be disposed along axis  310 . As may be appreciated, vent  304  may be formed by molding, drilling, grinding, milling or any other method well-known in the art without departing from the present invention. As may be further appreciated, vent  304 , as illustrated, has a diameter and position that is intended for illustrative purposes only. Thus, no dimensional limitation should be inferred from these illustrations. Rather, these illustrations are primarily intended to illustrate positional aspects only with respect to axes described herein.  
         [0031]      FIG. 3B  is an illustrative cross-sectional representation of a vented ceramic tip  320  having a plurality of vents  324 ,  326 , and  328  disposed along an axis  310  in accordance with embodiments of the present invention. As illustrated, ceramic wall  322  is disposed around an axis formed at the intersection of axes  330  and  332 . Vents  324 ,  326 , and  328  may be positioned equidistant from each other so as to enhance structural integrity of tip  320 . In other embodiments, vents  324 ,  326 , and  328  may be disposed more or less randomly distant from each other. As may be appreciated, vents  324 ,  326 , and  328  may be formed by molding, drilling, grinding, milling or any other method well-known in the art without departing from the present invention. As may be further appreciated, vents  324 ,  326 , and  328 , as illustrated, have diameters and positions that are intended for illustrative purposes only. Thus, no dimensional limitations should be inferred from these illustrations. Rather, these illustrations are primarily intended to illustrate positional aspects only with respect to axes described herein.  
         [0032]      FIGS. 4A-4C  are illustrative representations of vented ceramic tip usage in accordance with embodiments of the present invention.  FIG. 4A  is an illustrative representation of a vented ceramic tip  400 A before tip portion  406 A is introduced to a fluidic media  402 A. In the illustrated configuration, a single vent  404 A is utilized. Vented ceramic tip  400 B is then lowered into fluidic media  402 B as illustrated in  FIG. 4B . Fluidic media  402 B is drawn up and into vented ceramic tip  400 B to level  408 A as illustrated by arrow  410 B. Fluidic media is drawn up and into vented ceramic tip  400 B as a result of capillary action. Fluidic media rises to level  408 A which corresponds to a lower edge of vent  404 B. As illustrated, only a portion of tip portion  406 B is introduced to fluidic media  402 B unlike prior art systems quill systems which require full immersion into a solution to completely wet the quill.  
         [0033]     Vented ceramic tip  400 C is then raised out of fluidic media  402 C. Because of surface tension, fluidic media remains in vented ceramic tip  402 C and maintains level  408 B. Once tip potion  406 C is clear of fluidic media  402 C and any container being used to store fluidic media  402 C, vented ceramic tip  400 C may be repositioned to a slide where a fluidic spot may be deposited. Fluid is typically deposited when fluidic media stored in a vented ceramic tip touches a slide. Surface tension acts to draw a portion of the fluidic media onto a slide. Vent  404 C allows for control of volume drawn into vented ceramic tip  400 C as well as discourages vapor lock that may be caused by exiting fluid.  
         [0034]     While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents, which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. For example, although a vent cover is illustrated in FIGS.  2 B-C, a vent plug may be equally utilized to cover any vents. In that vein, any manner of closing or otherwise sealing a vent may be utilized without departing from the present invention. In another example, although vented ceramic tip is illustrated as being connected with a single shaft, as in  FIG. 1 , a number of vented ceramic tips may also be connected with a common manifold or print head without departing from the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.