Preface

Cellular microinjection techniques have developed over the last century along with the evolution of other biological fields. For example, developmental biologists have used a variety of microinjection techniques to transfer cytoplasm between cells, inject antibodies and peptides, and express foreign genes in specific tissues to advance their understanding of cell specification and determination. Molecular biologists finely craft glass microneedles and tools for the manipulation of cells in order to study gene expression and communication between cells. As these techniques have matured, microinjection has become accessible and, thus, exploited by a larger segment of the scientific and medical community. As more and more information is gathered from the various genome projects, demand grows for methods to validate these new data. Microinjection can help address this need. In particular, microinjection has proven valuable for the confirmation and extension of in vitro results in an in vivo setting – the living cell. The technique has also found a home in the clinical setting, most obviously within the community of fertility specialists for in vitro fertilization methods and for those excited about the possibility of therapeutic cloning. This book explores the use of microinjection for a wide range of scientific uses. There are special considerations for each application of microinjection – whether it is the injection of antibodies, fusion proteins, DNA, and in vitro-synthesized RNA or the production of transgenic animals. It is hoped that these methods will be of interest for all biologists for use in the research laboratory, as well as for clinicians interested in applying this powerful method for treatment in the clinic. 1. A Brief History of Microinjection The technique of microinjection was born of necessity and owes its history to a combination of fields. Credit for the initial description of a coherent microinjection technique could be given to Marshall Barber, who developed methods for producing fine glass capillary pipettes for isolating and manipulating single bacterial cells (1,2), or to the embryologist Laurent Chabry, credited with developing the glass microcapillary and micromanipulator as tools for his studies on teratology in ascidian blastomeres (3,4). Barber incorporated techniques into his injection method that are still used today, including the first use of mercury for controlling the movement of small volumes of fluid (see below) and the use of a second pipette to hold the cells as the injection is completed (5,6). The technique of microinjection moved from being a useful method practiced by a few resourceful scientists to an exciting mainstream application when Gurdon and colleagues demonstrated that