Our research is aimed at the advancement and application of "Dip-Pen Nanolithography" (DPN) and related methods like e.g. "Polymer Pen Lithography" (PPL).
DPN and PPL are versatile tools, combining advantages of electron beam lithography, inkjet printing and microcontact printing in relation to resolution, integration and throughput. These methods are of particular interest when working with sensitive biological materials, since they work at mild process parameters and need no lift off processes (with the associated solvents or etching processes). Furthermore, DPN allows for "multiplexing", i.e. the parallel application of different inks within a pattern. The achievable resolution is strongly dependant on the substrate/ink system and spans from <20 nm (thiols on gold) to about 100 nm (phospholipids on glass).
|Lipid DPN: Use of a parallel array of DPN pens which can write surfaces with different functional materials at the same time.|
A system of special interest for biological applications is the DPN with phospholipids (Lipid DPN). This method enables the generation of structured lipid membranes with a resolution of down to 100 nm and with different functional admixings. The height of the lipid membranes is adjustable and spans from a single lipid layer (~2 nm), over one to view lipid double layers up to layers of 200 nm thickness.
|Multiplexing and "sub-cellular integration": Two different proteins integrated on a sub cellular scale by lipid DPN (left) and a protein/dye pattern, immobilized by click-chemistry DPN (right).|