Recently piezo-based ink jet printers have proven to be reliable, productive manufacturing tools particularly where expensive materials are involved. As bioengineers, we are capitalizing on the ability of piezoelectric-based drop-on-demand ink jets printers to precisely deposit a wide variety of biologically active materials to create custom arrayed libraries and patterns. These applications and many others take advantage of ink jet strengths as an additive, non-contact process. We have developed disposable ink jet cartridges and a laboratory bench-top printing system. We have printed many biological materials, and optimization of ink compositions has been the focus of our research. At this conference, we will discuss both solvent-based and aqueous bioinks. We will show the spatial deposition of both nanoinks and microinks and show the resulting biomaterial designs and arrays including DNA, bacteria, proteins and carbon nanotubes. We have printed gold nanoparticles and protein-bound nanospheres to allow patterning of fluorescent proteins. We will discuss ink composition and printing characteristics of these materials. Finally we will discuss wave form parameters for printing a broad range of aqueous materials used in the biosciences and performance characteristics during printing.