Non-fouling PEG silane monolayer was desorbed from individually addressable ITO electrodes on glass by application of a reductive potential. Electrochemical stripping of PEG-silane layer from ITO microelectrodes allowed for cell adhesion to take place in a spatially defined fashion, with cellular patterns corresponding closely to electrode patterns.
Part I: Patterning of the electrodes
Part II: Surface modification
Note: This process is carried out in a glove bag filled with nitrogen to avoid presence of moisture, as PEG silane is reactive towards it.
Part III: Electrochemistry
Part IV: Cell patterning
In this video, we have demonstrated the cell patterning on optically transparent indium tin oxide electrodes. After fabricating the ITO electrodes using photolithography, they were modified with a cell-resistive monolayer of PEG silane. This monolayer was desorbed using electrochemistry switching the surface from cell-resistive to cell-adhesive. Patterning of 3T3 murine fibroblasts has been shown in his video. We have also patterning hepatocytes, primary cells, and stellate cells using the same technique. In addition, by making multiple individual electrodes, we can extend this technique to assemble multiple cell types. Furthermore, by controlling the geometry of the design, the cells can be spatially and temporally isolated on the surface.
Photolithography and wet etching techniques are standard microfabrication processes. Electrochemistry has been widely studied on gold surfaces but not so much on ITO. Apart from conductivity, ITO also provides advantage of transparency. By using ITO, the samples can be visualized using a simple inverted microscope. The technique presented in this video can be employed to assemble any cell type on the surface in a precise geometric pattern.
Material Name | Type | Company | Catalogue Number | Comment |
---|---|---|---|---|
Indium Tin Oxide | Other | Delta Technologies | CB 40IN | |
PEG silane | Reagent | Gelest Inc. | SIM6492.66 | |
Hydrochloric Acid | Reagent | Sigma-Aldrich | 320331 | |
Nitric Acid | Reagent | Sigma Aldrich | 258121 | |
Ethanol | Reagent | Sigma-Aldrich | 459836 | |
Acetone | Reagent | Sigma-Aldrich | 650501 | |
Toluene | Reagent | Sigma-Aldrich | 34866 | |
Media | Reagent | Invitrogen Technologies | ||
Collagen | Reagent | Sigma-Aldrich | C3867 | |
3T3 murine Fibroblasts | Cell Line | ATCC |