Cytoscribing: a method for micropositioning cells and the construction of two- and three-dimensional synthetic tissues.

Cells may be positioned in precise, predetermined patterns by a technique, termed cytoscribing, in which cell adhesion proteins are deposited on a substratum under computer control. Using standard office equipment, cells may be positioned within a cell diameter with the techniques described. Cytoscribing involves the use of either a computer-controlled ink jet printer or a graphics plotter to deposit cell adhesion proteins and monoclonal antibodies onto a substrate material. By selecting different cell adhesion proteins and methods that permit the formation of positive or negative patterns of cells (cytoscripts), two-dimensional tissues can be constructed. It is also demonstrated that an optical microlithography technique used in the semiconductor industry can be used to position cells with a precision of less than a micron. By utilizing the properties of cell adhesion proteins, both positive and negative cytoscripts of photoengraved images can be obtained. Techniques for the construction of three-dimensional tissues are described. Thin sheets of collagen were obtained by forming collagen heat gels in a mold. Monolayers of cells growing on thin collagen sheets were then attached to one another by gluing the sheets together with collagen. Sheets of cells do not attach to each other readily in the presence of fibronectin and evidence is provided which indicates that this observation is due to a lack of adhesiveness of the upper surface of cells.