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Application Examples

Micro-Contact-Printing of Fibronectin for LH929 cell growing

Selective adhesion of cells on planar substates can be achieved by printing of donut structures.

Silicon master chip with donut structures       Microscopic images of LH929 cells on planar substrates after 4h and 9h, respectively.

Micro-Contact-Printing of Fibronectin for stem cell adhesion and differentiation studies

Courtesy of EC Joint Research Centre, Nanobiosciences Unit, Ispra, Italy (Dora Mehn)

Human Umbilical Cord Blood Neural Stem Cells (HUCB-NSC) were grown on microcontact printed fibronectin squares for a differentiation study.

The squares were printed using PDMS stamp on a cell repellent, plasma polymerized poly-ethylene-oxide (PEO) like surface using fibronectin solution in an acetate buffer as an ink.				Phase contrast image
The cells do not adhere to the PEO coated regions, but are attached to the printed 100 µm fibronectin squares. After the culturing period the cells were fixed and immunostained for glial and neuronal differentiation markers.				Fluorescence image: Green: β-tubulin-II neuronal marker Red: GFAP Blue: Cell nuklei
				HUCB-NSC cells on micro-contact printed Fibronectin squares

Typical NIL (Nano-Imprint-Lithography) structures

A) and B): NIL microstructures in 20µm thick SU8 photoresist C) Silicon master chip with wet etched pyramid grooves, edge length = 4.5 microns D) Corresponding PDMS stamp surface

NIL for in vitro neurotoxicity assay development

Courtesy of EC Joint Research Centre, Nanobiosciences Unit, Ispra, Italy (Dora Mehn)

	Experimental Setup
Left: Electrodes of the MEA chip in the bottom of the 100 x 100 x 50 µm wells.    Right: Scanning electron microscopic image of one well of the microarray (by Cesar Pasqual Garcia)

Microelectrode array chambers (MEA chips) were applied as a support to generate 3D microwell environment for neural cells in electrical activity measurement studies.

The PVM (Predecessor of PVM-A) combined with the UV illumination and the 24 well stamp bodies were used to generate imprints with 100 µm sized wells and interconnecting channels				aligned to the electrodes of the multi-electrode arrays. The matrix of PEG based hydrogel was polymerized by 60 s UV treatment.
Primary (rat) neurons grown forming a network in the microwells; Green: β-tubulin-II neuronal marker, Blue: cell nuclei. (by Jakub Nowak)

Transferring of Glass Beads on Chip Surfaces by NIL

A planar stamp surface is used to pick up glass beads from the ink slide. The beads stick to the stamp bottom by adhesive forces. During the stamp process the beads are immersed into tbe SU8 layer on the substrate. In contradiction to lithographical patterned stamps the glass beads shape a non-regular layer on the resist.

	Schematic procedure of printing glass beads by NIL: The SU8 layer is hardened at 80°C onboard of µ-CP 3.0 (heatable substrate holder)		Bottom view of the PDMS stamp with sticking glass beads
			SEM image of the SU8-layer with semi-immersed glass beads

 

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