Printed digital microfluidic devices methods of use and manufacture thereof

Abstract

Embodiments of the present disclosure digital microfluidic arrays that may be fabricated by a printing method, whereby digital microfluidic electrodes arrays are printed, via a printing method such as inkjet printing, onto a suitable substrate. In some embodiments, a substrate and/or ink is prepared or modified to support the printing of electrode arrays, such as via changes to the surface energy. In some embodiments, porous and/or fibrous substrates are prepared by the addition of a barrier layer, or, for example, by the addition or infiltration of a suitable material to render the surface capable of supporting printed electrodes. Various example embodiments involving hybrid devices formed by the printing of digital microfluidic arrays onto a substrate having a hydrophilic layer are disclosed.

What is claimed is: 
     
         1 . A method of fabricating a digital microfluidic device, the method comprising:
 providing a porous substrate;   printing, with a conductive ink, an array of digital microfluidic electrodes onto said porous substrate; and   coating said array of digital microfluidic electrodes with a dielectric layer having a hydrophobic surface;   wherein said porous substrate has a surface roughness such that a surface roughness of said digital microfluidic device, after coating said array of digital microfluidic electrodes, is less than approximately 1 micron;   wherein said conductive ink and a surface of said porous substrate are selected such that a surface energy of droplets of conductive ink printed on said porous substrate are suitable for forming said electrodes; and   wherein said array of digital microfluidic electrodes are printed such that an inter-electrode trench depth, and inter-electrode trench width, and the surface roughness of said array of digital microfluidic electrodes are suitable for transporting droplets among electrodes under electrical actuation.   
     
     
         2 . The method according to  claim 1  further comprising modifying a surface chemistry of said surface prior to printing said array of digital microfluidic electrodes, such that a surface energy of droplets of conductive ink printed on said porous substrate are suitable for forming said electrodes. 
     
     
         3 . The method according to  claim 1  further comprising modifying a surface chemistry of said surface prior to printing said array of digital microfluidic electrodes, such that a surface energy of droplets of conductive ink printed on said porous substrate are suitable for forming said electrodes. 
     
     
         4 . The method according to  claim 1  wherein said surface roughness of said porous substrate is less than approximately 1 micron. 
     
     
         5 . The method according to  claim 1  wherein said substrate is a porous substrate comprising a porous layer having a barrier layer provided thereon. 
     
     
         6 . The method according to  claim 1  wherein said substrate is a porous substrate, wherein at least an upper portion of said porous substrate is infiltrated with a material. 
     
     
         7 . The method according to  claim 1  wherein said substrate is formed from an insulator. 
     
     
         8 . The method according to  claim 7  wherein said insulator is glass. 
     
     
         9 . The method according to  claim 1  wherein said substrate is formed from a semiconductor. 
     
     
         10 . The method according to  claim 1  wherein said substrate is formed from a polymer. 
     
     
         11 . The method according to  claim 1  wherein said array of digital microfluidic electrodes is printed with an inkjet printer. 
     
     
         12 . The method according to  claim 1  wherein said array of digital microfluidic electrodes is printed with a printing method selected from the group consisting of screen printing, flexography, gravure, offset lithography, micro-contact printing, and aerosol jet printing. 
     
     
         13 . The method according to  claim 10  wherein said polymer is selected from the group consisting of polyester, polyimide, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). 
     
     
         14 . The method according to  claim 1  wherein said conductive ink comprises metallic nanoparticles. 
     
     
         15 . The method according to  claim 1  wherein said conductive ink comprises an organic polymer ink. 
     
     
         16 . A method of fabricating a digital microfluidic device, the method comprising:
 providing a substrate;   printing, with a conductive ink, an array of digital microfluidic electrodes onto said substrate; and   coating said array of digital microfluidic electrodes with a dielectric layer having a hydrophobic surface;   wherein said substrate has a surface roughness such that a surface roughness of said digital microfluidic device, after coating said array of digital microfluidic electrodes, is less than approximately 1 micron; and   wherein said conductive ink and a surface of said substrate are selected such that a surface energy of droplets of conductive ink printed on said substrate are suitable for forming said electrodes.