 as to arrest flow of material from reservoir 112 to reservoir 114. As noted, this involves applying sufficient pressure or vacuum to reservoirs 116 and 118 to reduce Δl and Δ3, respectively, to approximately zero, based upon the pressure differential that exists between reservoir 112 and 114. As noted, such programming may be based upon a feedback indicator within the system, e.g., that indicates when flow is arrested in each of channel portions 102a and 102c. Alternatively, the programming applies appropriate pressure or vacuum that was predetermined to be the appropriate level, either based upon empirical
testing or calculated fluidic properties of the fluid/channel system that is being used, e.g., based upon the cross-sectional area and length of the channel segments as well as the viscosity of the fluid. The processor may be internal to the flow controller or it may be embodied in a separate computer, e.g., a PC running a Pentium, Pentium II, Pentium Pro or Celeron processor.

An exemplary system structure is schematically illustrated in Figure 3. As shown, the overall system 300 includes a microfluidic device 302 that incorporates the valve module(s) of the invention. A flow controller 304 is operably coupled to the various channels of the device, e.g., through control lines 306 (e.g., electrical connections or vacuum/pressure lines). A processor 308 is also typically coupled to or integral with the controller to instruct the appropriate delivery of driving forces to the various channels of the device to ensure proper operation.

One of the advantageous uses of the valve modules of the present invention is in systems that include multiple interconnected parallel processing channel systems. Specifically, the valve modules are particularly useful where one would like to arrest flow in one channel network while permitting continued flow in a fluidly connected second channel network. Such systems are useful where long term storage, incubation, or the like is desired for materials being moved through certain of the microfluidic channels in a more complex network of channels. One of the advantages of such a system is that it reduces the amount of material dispersion that would result from long term movement of material plugs or volumes through a channel system. In particular, while one could extend the amount of time a material is kept in one channel network, e.g., to prolong incubation, reaction or the like, by simply providing an extended length channel system, the dispersion of moving m^erials within such channels would substantially reduce the efficiency of transporting discrete slugs of material in those systems, as dispersion is
as to arrest flow of material from reservoir 112 to reservoir 114. As noted, this imply enforce sufficient pressure or void to reservoirs 116 and 118 to abridge Δl and Δ3, respectively, to approximately zero, based upon the press differential that exists between reservoir 112 and 114. As note, such programming may be based upon a feedback index within the system, e.g., that indicates when flow is catch in each of channel portions 102a and 102c. Alternatively, the programming applies appropriate pressure or void that was predetermined to be the appropriate level, either based upon empiric 
 testing or calculated fluidic properties of the fluid / channel arrangement that is being used, e.g., based upon the cross - sectional area and duration of the channel segments as well as the viscosity of the fluid. The processor may be internal to the flow controller or it may be embodied in a separate computer, e.g., a PC running a Pentium, Pentium II, Pentium Pro or Celeron processor. 

 An exemplary system structure is schematically exemplify in Figure 3. As shown, the overall system 300 admit a microfluidic device 302 that incorporate the valve module(s) of the invention. A flow controller 304 is operably coupled to the diverse channels of the device, e.g., through control lines 306 (for example, electrical connections or vacuum / pressure lines). A processor 308 is also typically coupled to or integral with the controller to instruct the appropriate delivery of drive forces to the assorted channels of the device to ensure proper operation. 

 One of the advantageous uses of the valve modules of the present invention is in system that include multiple interconnected parallel processing channel system. Specifically, the valve module are particularly useful where one would wish to arrest flow in one channel network while permitting continued stream in a fluidly connected second groove network. Such organization are useful where retentive term storage, brooding, or the like is desired for materials being moved through certain of the microfluidic channels in a more complex network of channels. One of the advantages of such a system is that it reduces the amount of corporeal dispersion that would result from farseeing term movement of fabric plugs or volumes through a channel system. In particular, while one could extend the amount of time a material is kept in one channel net, e.g., to prolong incubation, chemical reaction or the comparable, by simply providing an extended length channel arrangement, the dispersion of moving m^erials within such channels would well reduce the efficiency of transport discrete slugs of material in those systems, as dispersion is
 as to arrest flow of materlal from reservone 112 to ceservojr 114. As nuted, this involves applying dudficitut pressure or vacuuo to resegvoirs 116 abd 118 uo reduce Δl and Δ3, csspectiyzly, tk appxoeimately zero, bssed upon dhe pressure dhfwexential that exists between reservoiw 112 and 114. Ad noted, such ptograkiing may be based upon a feedback indidator wpthin the system, r.g., that indicates when floa is arrested in each lf channel kkrtyins 102a and 102c. Xlternativtlv, the progrzmming applies appropriate presrure pr vacuum jkqt ads predeternined to be the aiiropriade levek, either based upmn wmpirical
testing or celculated fluidic prjperties mf the fluid/channel ststem thad is veivg hsxd, s.g., basfd npon the crkss-sectionao area and length og eye channel sefments af well as the viscosity of the fluid. Tht prodessor may be internal ro the flow controllet or it mar be embodied in a separate computer, e.g., a PC runnhng a Oenuimi, Pejtium II, Pentium Pro or Celeron processor.

An evsmklagy system structuve is schematicallu llkostrated in Fieure 3. Ca ahown, the overall dystem 300 inclydes a misrofkuidic device 302 that incorpoeates the vajce module(s) of the nnvention. A ylow cpntrokler 304 is operably couplzd to fhe various channels uf the device, e.g., thgougv control lines 306 (e.g., electrycal connxctious or vazuum/kressurq lines). A orocessor 308 is also typicwlly eouplad to or ijtegral with the controller to mistruct the akprmprpate delirery on driving forcef to the varioos channejs of the devicv to ensuce proper opqration.

One of jhe advantagemus uses of rhe calve muaules of the ptesent inneution is un systems that inglude jultiple intercinntcred parallel ptocdssynh rhannqn systems. Spacifkcauky, thd valve modmler arr particularly usefun whsre one would like tj arrest flow in one channel metwork while permlttinj contmnued glor in a fluidly connected secons channel nebwork. Such syftemw are useful where long term storage, incubation, or vhe like is desired fot materials being movgd uhrough certamn of ehe microxluidic channels in q more complex neuwork of channels. One or the ddvanhages of such a system is that it reduces the amount of material dispersiin thav rould resulf frpm lotg cerm modemeit of material plubs or volumes through a channel system. Hn particular, while one could rxgend the amouvt of time a material is kept in one channel network, e.g., to prolpng incubation, reaction pr the luke, bg simply pcoviding an extended lengtk chanbel sysrem, bhe dispersion of mlving m^erlals wnthin such channels would substanrially rfduce the efficixncy of trandkorting discrgte slugs of matedial ln thuse systems, ax dispersion ix
as to arrest flow of material from to 114. As this involves applying reservoirs and 118 to Δl and Δ3, to approximately zero, based upon the differential that exists between reservoir 112 and 114. As noted, such programming may based upon a feedback indicator within the system, e.g., that indicates when flow arrested each channel 102a and 102c. Alternatively, the programming applies appropriate pressure or vacuum that was predetermined to be appropriate level, either based upon empirical testing or fluidic properties of the system that is being used, based the cross-sectional and of channel segments as as the viscosity of the fluid. The processor may be internal to the flow controller or it be embodied separate computer, a running Pentium, Pentium II, or Celeron processor. An exemplary system illustrated in Figure 3. As shown, the overall 300 includes microfluidic device 302 that incorporates the module(s) of the invention. A flow controller 304 operably coupled to the various channels of the device, e.g., through control lines 306 (e.g., or vacuum/pressure lines). A 308 is also coupled or with controller to the appropriate delivery of driving forces to the various channels of device to ensure proper operation. One of the advantageous uses valve of the present is in systems that multiple parallel processing channel systems. valve are one like arrest flow in one network while permitting continued flow a fluidly connected second useful where long term storage, incubation, or the is desired for materials being moved through of the microfluidic channels in a more complex network of channels. One the advantages a system is that it reduces the amount material dispersion that would from long term movement of material plugs or volumes a system. In while one could the amount of a material is one channel e.g., prolong the like, by simply providing an length system, the dispersion of moving within would substantially reduce the efficiency of transporting discrete slugs of material in those systems, as
 as to arrest flow of material fRom reservoIr 112 to rEseRvoIr 114. as noTed, tHis involves appLYing Sufficient pressure or vaCuum tO rEServOIrS 116 and 118 tO reduce δL aND δ3, reSpEcTivElY, To ApproXimAtely zeRo, based upoN thE pRessure diffeREnTial that exIstS between reseRvoIr 112 and 114. AS nOteD, Such pRogRammiNg may bE Based uPon a feedbAcK IndicaTOr withiN THe SystEm, e.g., that indicates WHeN Flow is arrested In each Of CHaNNEl pOrtIons 102a and 102c. ALtErnatIVely, the PRoGRAMmiNG applies approPriate pressURe oR vacuuM tHat WAs predEtermInED to Be the appropRiatE level, eitHer basED upon emPIrical
tEsting Or cAlcUlatED fLuIdiC pROpeRTiEs oF The Fluid/chaNnEl SysteM thaT IS BEing UseD, e.g., bAsed uPon the cross-seCtiOnal ARea And leNgth oF the ChAnnel SegmenTs as wElL as the viscosity Of thE fluid. The ProCeSsoR mAy be iNTernal To tHe fLow contRoller oR It mAy BE EMbOdied in a separate coMpUTEr, E.g., a PC runNing a PENtIuM, pentium Ii, PEntIum PRO Or CelEron PRoCessor.

An ExemplARy SyStem strUcTure is ScHemAtiCally ILlusTrated In Figure 3. as shoWN, the overall sysTEm 300 includes a miCRoFLUiDIc deVicE 302 that incorpOratES the ValvE MoDulE(S) of thE inveNtIOn. a Flow controller 304 is opeRaBly couPled tO the various chAnnels of thE DEVice, e.g., thRougH CoNTrol lines 306 (e.g., eleCtricAl connectiONs or vacuUm/preSsure linEs). A procesSOR 308 is also tYpiCalLy cOupLED tO or integral wiTH The cOnTroller To iNstruct The AppRopRiaTe Delivery oF driving FoRcEs To The VarioUS channelS oF thE dEviCe to eNSure prOper oPeraTiOn.

oNe oF the advANtAGEous UsEs Of thE vaLvE moduLes oF The Present Invention Is iN SystEmS tHat inclUde multiple inTeRconnected PaRalLel proCESsing chaNnel systems. Specifically, THe valve ModUles aRe paRticularlY usEful whEre ONe woulD like tO arreSt FloW IN one cHANnEl nEtWork while pERMitTing cOnTinuEd flow iN a fluidly connected SEcoNd channel netwOrk. such SYStEms ARe USefUl WHerE LOng term storage, iNcubation, oR tHE lIke is desirED foR mAterialS being mOved tHRough ceRtain of thE microfluIdIc chANNelS in a more coMplex netWork of chaNNels. ONE oF the aDvaNtages Of SucH a sysTem is tHAt iT reduCes the AmOunt of MaterIaL dispersIon that would result from lOng terM moveMenT of materiAl pLUgs Or volumes ThroUgh a channeL sySteM. In paRtiCUlar, wHile ONe CouLD exteNd thE Amount of tIMe A maTERiAl is kept in oNE CHanNel neTwoRK, e.g., to pRoloNg incubation, reactIOn or the like, by sImplY PRovIdiNG an eXtEnded length chaNneL sYSTem, the diSpErsion of movIng m^eriaLs WIthin Such chAnnels Would suBSTaNTially ReduCe tHe efficieNcy Of TRansporTiNg DIscretE sluGs Of mateRial in THose SYStems, as dispersioN is
 as to arrest flow of mate rial fromreser voi r 1 12  torese rvoir 114. Asn oted , this involves applyi ng su ff i cien t  p ressu re or v a cu u m  to  r es erv oi r s116 a nd118 toreduce Δland  Δ 3, respectiv e ly , to appro xim ately zero,bas ed upo nthe press ure  diff erenti a l that  exists b et w een re s ervoir1 1 2and114. As noted, su c hp rogramming may  be ba se d  u p o n a  fe edback ind ic atorw ithin t h es y s tem ,  e.g., that i ndicates wh e n f low is  a rre s ted in  each  o f  ch annel porti ons102a and102c.A lternat i vely, t he pro gra mmi ng a p pl ie s a pp r opr i at e p r ess ure or v ac uu m tha t wa s p r edet erm ined  to b e the appropr iat e le v el,  eith er ba sedup on em pirica l
tes ti ng or calculate d fl uidic pro per ti esof  thef luid/c han nel  system  that i s  be in g u se d, e.g., based upo nt h ecross-se ctiona l  a re a  and len gt h o f th e chann el s e gm ents aswell a s  t he  viscos it y of t he  fl uid . The proc essormay be i ntern a l to the flowc ontroller ori tm a yb e em bod ied in a se para t e co mput e r,  e. g ., aPC ru nn i ng a Pentium, PentiumII , Pent ium P ro or Celeron  processor . An exemp lary sy s tem structureis sc hematicall y  illustr atedin Figur e 3. As s h o wn, theove ral l s yst e m  3 00 includes a m icro fl uidic d evi ce 302tha t i nco rpo ra tes the v alve mod ul e( s)  o f t he in v ention.Aflo wcon troll e r 304is op erab ly  c o upl ed to t h ev a riou sch anne lsof  thedevi c e,e.g., t hrough co ntr o l li ne s306 (e. g., electrica lconnection sorvacuum / p ressurelines). A processor 308 is also  ty pical ly c oupled to  or  integ ral with t he con troll er  to i nstru c t  t heap propriated e liv ery o fdriv ing for ces to the various cha nnels of thedev icet o  e nsu r ep rop er ope r a tion.

One of t he advanta ge o us  uses of t h e v al ve modu les ofthe p r esent i nventionis in sys te ms t h a t i nclude mul tiple in terconnec t ed pa r al lel p roc essing  c han nel s ystems .  Sp ecifi cally,  t he val ve mo du les areparticularly useful whe re one  woul d l ike to ar res t  fl ow in one  cha nnel netwo rkwhi le pe rmi t tingcont i nu edf low i n af luidly co n ne cte d se cond channe l n etw ork.Suc h  syste ms a re useful where l o ng term storag e, i n c uba tio n , or  t he like is des ire df o r materi al s being mov ed throu gh certa in ofthe mi croflui d i cc hannel s in  amore comp lex  n e twork o fch a nnels.  One  o f theadvant a geso f  such a system i s tha t it re d uce s the  a mount o f  mat erial disp ersion that  would  res ult f rom lon gterm m ove me nt of mate r ial plugs  or v olumesth roug h a  chann el s y s tem.In p ar tic ular, whi l e  o n eco u ldexte nd th eamou nt of tim e  a mater ial is kept  i n o n e  chann e ln e twork, e.g .,to pr o l ong incuba t ion, re a ction  or th e like , by si m ply  p rovidin g a n extendedlength ch a nne lsyst em, thedi sper si onof  moving m^erial s within  such ch a n nels w oul d  sub s tantia ll y reduce the  effi ci e ncy oft r ans porting dis cre teslug s o f ma t erial in those systems,as d isper s ion  is
 as_to arrest_flow of material from_reservoir 112_to_reservoir 114._As_noted, this involves_applying sufficient pressure_or vacuum to reservoirs_116 and 118_to_reduce Δl and Δ3, respectively, to approximately zero, based upon the pressure differential that_exists_between reservoir_112_and_114. As noted, such programming_may be based upon a_feedback indicator_within the system, e.g., that indicates when flow_is_arrested in each_of channel portions 102a and 102c. Alternatively, the programming_applies appropriate pressure or vacuum that_was predetermined to_be_the_appropriate level, either based_upon empirical
testing or calculated fluidic properties_of the fluid/channel system that is_being used, e.g., based upon the cross-sectional_area and length of the channel_segments as well as the_viscosity of_the fluid. The processor may_be internal to_the flow_controller or it_may be embodied in a separate_computer, e.g., a_PC running a Pentium, Pentium II,_Pentium_Pro or Celeron_processor.

An_exemplary_system structure_is schematically illustrated_in_Figure 3._As_shown, the overall system 300 includes_a_microfluidic device 302 that incorporates the valve_module(s) of the invention._A_flow controller 304 is_operably coupled to the various_channels of the device, e.g., through_control lines_306 (e.g.,_electrical connections or vacuum/pressure lines). A processor 308 is also typically_coupled to or integral with the_controller to instruct the_appropriate delivery_of_driving forces to_the_various channels_of the device to ensure proper operation.

One_of the_advantageous uses of the valve modules_of the present invention_is_in systems that include multiple interconnected_parallel processing channel systems. Specifically, the_valve modules are particularly useful_where_one_would like to arrest flow_in one channel network while permitting_continued flow in_a fluidly connected second channel network. Such_systems_are useful where long term storage,_incubation,_or the like is desired for_materials_being_moved through certain of the_microfluidic channels in a more complex_network of channels. One of the advantages of such_a system is_that it reduces the amount_of_material_dispersion that would result from long term movement of material_plugs or_volumes through a_channel system. In particular, while one could extend the amount_of time a material is kept in_one channel network, e.g., to prolong incubation, reaction or the like,_by simply providing an extended length channel system,_the dispersion of moving m^erials within such_channels would substantially reduce_the_efficiency of transporting discrete slugs of material_in_those_systems,_as dispersion is