Patent Application: US-49412204-A

Abstract:
a surface energy gradient on a fluid - impervious surface and method of its creation comprising the steps of a ) exposing a base surface having a proximal and a distal portion to a first solution comprising at least one molecule of the formula x - j - m 1 wherein x and m 1 represent separate functional groups and j represents a spacer moiety that , together , are able to promote formation from solution of a self - assembled monolayer for sufficient time to form a monolayer surface having a uniform surface energy on the base surface . b ) removing a portion of the monolayer of such that a portion of the base surface is again fully or partially exposed . exposing the portion of the base surface from to at least one other molecule including a functional group having a different surface energy from that of the functional group removed in such that a surface energy gradient from a proximal location to a distal location is formed .

Description:
while this invention may be embodied in many different forms , there are described in detailed herein specific preferred embodiments of the invention . this description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated . as used herein , the term “ tube ” is any hollow object open on two sides without limitation by cross - sectional geometries . turning now to the drawings , fig1 shows a blown - up schematic view of an embodiment of the method for producing a mixed monolayer surface energy gradient . the view consists of 6 slides . slide ( a ) shows a base surface 1 having a monolayer 3 . the original monolayer is made up of a plurality of first organic molecules 5 . the base surface 1 having a monolayer 3 can be stored and used later as well . the first organic molecules 5 are comprised of a functional group 7 ( e . g . thiol ) that reacts with the base surface 1 and a low surface energy functional group 9 ( e . g . ch 3 , cf 3 , etc ). the instrument 11 is not in contact with the monolayer 3 at this point of the process . the instrument 11 in slide ( b ) comes into contact with the monolayer 3 and removes some of the original monolayer 3 as the instrument 11 passes along the surface 1 . at the same time , second organic molecules 13 are added . the second organic molecules 13 are comprised of a functional group 7 designed to react with the base surface 1 and a high surface energy functional group 17 ( e . g . oh , co 2 h , conh 2 , etc ). slide ( c ) shows how some of the second organic molecules 13 are reacting with the base surface 1 and creating a mixed sam layer . as shown in slide ( d ), this process continues as the instrument 11 continues along the base surface 1 . more second organic molecules 13 are being added and are reacting with the exposed base surface 1 . this continues through slide ( e ) and in slide ( f ) a higher concentration of high energy groups 17 make up the monolayer 3 and along the portion of the surface the instrument 11 passed a surface energy gradient 19 is formed . fig2 shows a blown - up schematic view of the method during the removal and exposure steps wherein the instrument 11 that removes the sam layer 3 also delivers new molecules 13 to the base surface 1 . in this manner the mixing of first molecules 5 and second molecules 13 is performed near the base surface 1 as the instrument 11 delivers second molecules 13 from the instrument reservoir 21 . the instument 11 can have the new molecules 13 stored in the instrument reservoir 21 inside the instrument 11 or added to the instrument 11 by tool 23 as the instrument 11 passes along the surface 1 . fig3 shows a blown - up schematic view of the method during the removal and exposure steps wherein the instrument 11 that removes the sam layer 3 also delivers new molecules 13 to the base surface 1 . in this manner the mixing of first molecules 5 and second molecules 13 is performed inside the instrument reservoir 21 and then the mixture is delivered near the base surface 1 as the instrument 11 delivers second molecules 13 from the instrument reservoir 21 . the instrument 11 can have the new molecules 13 stored in the instrument reservoir 21 inside the instrument 11 or added to the instrument 11 by tool 23 as the instrument 11 passes along the surface 1 . fig4 illustrates another method of mixing . here , the mixing method has similarities to those illustrated in fig2 and fig3 , however the mixing of molecules is performed in an outside reservoir 25 . the mixed molecules are then transferred into the instrument reservoir 21 by means of a line 27 . in fig5 , the mixed - sam surface 29 reacts with nhs to produce a surface with an increasing concentration of nhs ester ( step b ). it should be noted that the portions of the ch3 - co2h mixed monolayer that do not take part in the reaction are not shown ( e . g . ch3 ). various proteins 31 containing lysine groups can then be adsorbed by nhs - surfaces 33 ( step c ). the nhs - surface 33 functions to self - propel or reduce the external force requirements necessary for propulsion of a liquid ( e . g . blood ) while removing protein molecules from the liquid . similar designs could have a wide application in analyzing blood , other protein - bearing liquids , and liquids containing oligo - strands of dna , as well as antigen / antibody combinations . this nhs - surface and other such surfaces use sam surfaces such as these , with properties tailored to adsorb specific molecules , and provides means to effectively decrease the necessary dimensions of such analytical systems . this system could also be applied to stent technology so as to remove harmful proteins or fats from collecting in arteries and other such body lumens . fig6 illustrates a method for creating a surface energy gradient on the inside of a tube 35 . in this instance , the instrument 11 is in contact with the uniform surface energy monolayer on the inside walls of the tube 35 and moves along the inside of the tube 35 in a direction longitudinal to the longitudinal axis 37 removing the uniform surface energy monolayer . the second organic molecules having a different functional group than that of the removed monolayer can be in solution above the instrument in upper area 39 , below in lower area 41 , or in both upper area 39 or lower area 41 . the solution can also flow through a hollow cavity in the instrument 11 so as to reach the surface to be treated . as more second organic molecules are added a greater number will react with the portion of the tube which has had the uniform surface energy monolayer removed . in this way a longitudinal gradient is created on the inside walls of the tube 35 . fig7 illustrates a similar method for creating a surface energy gradient on the inside of a tube 35 . however , in this instance , the instrument 11 is in contact with the uniform surface energy monolayer on the inside walls of the tube 35 and moves along the inside of the tube 35 in a rotational direction about the longitudinal axis 37 removing the uniform surface energy monolayer . the second organic molecules having a different functional group than that of the removed monolayer can be in solution above the instrument in upper area 39 , below in lower area 41 , or in both upper area 39 and lower area 41 . the solution can also flow through a hollow cavity in the instrument 11 so as to reach the surface to be treated . as more second organic molecules are added a greater number will react with the portion of the tube which has had thee uniform surface energy monolayer removed . in this way a gradient is created on the inside walls of the tube 35 about a strip on the radius . fig8 illustrates a schematic of the pattern of surface energy gradient 43 created if the instrument 11 from fig7 is in contact with the uniform surface energy monolayer on the inside walls of the tube 35 and moves along the inside of the tube 35 in a rotational direction about the longitudinal axis 37 and in a longitudinal direction along the longitudinal axis 37 removing the uniform surface energy monolayer . the second organic molecules having a different functional group than that of the removed monolayer can be in solution above the instrument in upper area 39 , below in lower area 41 , or in both upper area 39 or lower area 41 . the solution can also flow through a hollow cavity in the instrument 11 so as to reach the surface to be treated as more second organic molecules are added a greater number will react with the portion of the tube which has had the uniform surface energy monolayer removed . in this way a gradient is created on the inside walls of the tube 35 in a spiral type pattern . fig9 illustrates a method for creating a surface energy gradient on the outside side of a tube 35 . in this instance , the instrument 11 is in contact with the uniform surface energy monolayer on the outside walls of the tube 35 and moves along the outside of the tube 35 in a direction longitudinal to the longitudinal axis 37 removing the uniform surface energy monolayer . the direction of the instrument &# 39 ; s movement can also be rotational about the longitudinal axis 37 or a combination of rotational and longitudinal movement thereby creating a spiral gradient on the outside of the tube . the second organic molecules having a different functional group than that of the removed monolayer can be in solution above the longitudinal instrument contact point 45 in upper area 39 , below in lower area 41 , or in both upper area 39 or lower area 41 . the solution can also flow through a hollow cavity in the instrument 11 so as to reach the surface to be treated . as more second organic molecules are added a greater number will react with the portion of the tube which has had the uniform surface energy monolayer removed . in this way a gradient is created on the outside walls of the tube 35 . fig1 and 11 illustrate how the surface energy gradient can be created on only specific portions of the tube . by employing the same methods and mechanisms as those of fig6 , 8 , and 9 with the addition of teeth 47 even more specific portions of surface energy gradient can be created on the inside of the tube 35 as in fig1 and the outside of the tube as in fig1 . while this invention may be embodied in many different forms , there are described in detail herein specific preferred embodiments of the invention . this description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated . for the purposes of this disclosure , like reference numerals in the figures shall refer to like features unless otherwise indicated . the above disclosure is intended to be illustrative and not exhaustive . this description will suggest many variations and alternatives to one of ordinary skill in this art . all these alternatives and variations are intended to be included within the scope of the claims where the term “ comprising ” means “ including , but not limited to ”. those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims . further , the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims . for instance , for purposes of claim publication , any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction ( e . g . each claim depending directly from claim 1 should be alternatively taken as depending from all previous claims ). in jurisdictions where multiple dependent claim formats are restricted , the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent - possessing claim other than the specific claim listed in such dependent claim below . this completes the description of the preferred and alternate embodiments of the invention . those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto . such information as may be found relating to portions of this application include : kataoka , dawn e . and troian , sandra m ., “ patterning liquid flow on the microscopic scale ,” nature , vol . 402 , december 1999 , pp . 794 - 797 . kim , h ., graupe , m ., oloba , o ., koini 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evans , d ., “ structure and frictional properties of self - assembled surfactant monolayers ,” langmuir , 1996 , vol . 12 , pp . 1235 - 1244 . patel , n ., davies , m ., hartshorne , m ., heaton , r ., roberts , c ., tendler , s ., and williams , p ., “ immobilization of protein molecules onto homogenous and mixed carboxylate - terminated self - assembled monolayers ,” langmuir , 1997 , vol . 13 , pp . 6485 - 6490 . pfahler , j , harley , j ., and bau , h ., “ liquid transport in micron and submicron channels ,” sensors and actuators , a21 - 23 , 1990 , pp . 431 - 434 . tsukruk , v ., and bliznyuk , v ., “ adhesive and friction forces between chemically modified silicon and silicon nitride surfaces ,” langmuir , 1998 , vol . 14 , pp . 446 - 455 . xiao , x ., hu , j ., charych , d ., and salmeron , m ., “ chain length dependence of the frictional properties of alkylsilane molecules self - assembled on mica studied by atomic force microscopy ,” langmuir , 1996 , vol . 12 , pp . 235 - 237 . xu , s ., miller , s ., laibinis , p , and liu , g ., “ fabrication of nanometer scale patterns within self - assembled monolayers by nanografting ,” langmuir , 1999 , vol . 15 , pp . 7244 - 7251 . u . s . pat . no . 6 , 235 , 340 u . s . pat . no . 5 , 512 , 131 u . s . pat . no . 5 , 776 , 748 u . s . pat . no . 4 , 690 , 715 u . s . pat . no . 5 , 620 , 850 u . s . pat . no . 5 , 079 , 600 all us patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety .