Biopatterning

Microcontact printing is a simple and excellent method for directly patterning biomolecules on surfaces. Inking a stamp is done by simply adsorbing proteins from solution on the hydrophobic surface of a PDMS stamp. After rinsing, drying, and placing the stamp in contact with a surface, adhesion forces cause proteins to transfer from the stamp to the printed surface, Figure 1. We were able to demonstrate that this transfer occurs with high yield and great accuracy, Figure 2, and also that a large variety of biomolecules (cell adhesion molecules, antibodies, enzymes…) can be printed on different types of surfaces while remaining active. This allows us to create functional patterns of proteins at scales that involve the placement of <1000 molecules in well-defined locations on a surface (Figure 3, left) and even to print arrays of single antibody molecules using stamps having sub-100-nm molded features (Figure 3, right). Together with Dimitri Stamou, Klaus Duschl and Horst Vogel (EPFL), we showed how to prepare large arrays of single vesicles by microcontact printing ligands on a glass surface and using a strategy based on self-assembly, Figure 4.

Affinity microcontact printing is what we call the variant where the stamp bears receptors for specific biomolecules. The receptors immobilized on the stamp can be antibodies covalently attached to the stamp. These antibodies bind specific antigens from an ink solution and releases them on a surface by means of printing, Figure 5. Such stamps can be inked and used to print several times. Together with scientists from the Biochemistry Institute of the University of Zurich, we have shown that neuron-glia cell adhesion molecules can be directly inked on a stamp from tissue homogenates and printed on polystyrene to stimulate the attachment of neuronal cells and guide the growth of axons. We also developed several methods to prepare stamps for affinity microcontact printing.