Microinjection of DNA/mRNA/morpholinos is a critical technology for molecular biology and drug discovery. When dealing with suspended cells, state-of-the-art manual injection involves a time-consuming and tedious sample preparation procedure, to accurately align cells. To enable automatic microrobotic cell injection, this paper reports on two inexpensive, reusable, biocompatible, and easy-to-make devices that are capable of patterning a large number of cells in 10-30 seconds. One device is based on negative air pressure and made of polycarbonate using a conventional micro-machining process. It is particularly suitable for cells larger than 100 mum, such as the zebrafish embryo patterning and successful gene 'knock-down' products of the morpholino-injected embryos. The other device is based on dielectrophoresis and suitable for cells smaller than 100 mum, demonstrated by successful trapping of pituitary cells. These devices offer a complete solution for suspended cells in all size spectrums to be prepared up to 10 times faster than manual human preparation. Furthermore, this approach can facilitate high-throughput automatic microrobotic cell injection, for injection applications such as the injection of zebrafish embryos, mouse oocytes/embryos, Drosophila embryos, and other types of suspended cells.