Laser inactivation protein patterning of cell culture microenvironments

Protein micropatterned substrates have emerged as important tools for studying how cells interact with their environment, as well as allowing useful experimental control over, for example, cell shape and cell position on a surface. Here we present a new approach for protein micropatterning in which a focused laser is used to locally inactivate proteins on a protein-coated substrate. By translating the laser relative to the substrate, protein patterns of essentially arbitrary shape can be produced. This approach has a number of useful features. To begin, it is a maskless writing approach. Thus new patterns can be designed and implemented quickly. Laser inactivation can also be performed on a number of different substrate materials, ranging from glass to polydimethylsiloxane. Further, the inactivation is dose dependent, thus complex gradients and other non-uniform distributions of proteins can be produced. Because the focus of the laser can be changed quickly, laser-based patterning can also be applied to substrates with complex topographies or enclosed surfaces--as long as an optical path is available. To demonstrate this capability, protein patterns were made on the inside of small quartz capillary tubes. Patterned substrates produced using laser inactivation constrain cell shape in predictable ways, and we show that these substrates are compatible with a number of different eukaryotic cell lines.