Needle Microinjection: A Brief History

Since its inception in the early 1900’s (Barber, 1911), the technique of needle microinjection has become a prominent experimental approach in biological research. Cellular organelles, DNA and RNA, enzymes, structural proteins, metabolites, ions and antibodies are just some of the molecular and cellular elements that have been transposed from test tubes into living cells by needle injection. A simple search of the literature indicates the growing popularity of the technique, returning a few citations in the 1970’s, and thousands in the 1990’s. As a complementary approach to DNA transfection, and as one of only a few viable ways to introduce non-genetic, large molecules into living cells, microinjection is now routinely used to study many living cell systems. With an inherent immediacy, microinjection has facilitated a wide range of biological studies, some of which are described in this book. While numerous alternative “microinjection” tools have also been developed, such as vesicle fusion, scrape loading and electroporation, we will focus mainly on the versatility of the use of needles to facilitate cellular injection. Lastly we apologize to all of our colleagues whose exciting work could not be mentioned, and for any inadvertent errors of fact we may have made in this brief chapter. Many additional references can be found in the ensuing chapters, however, and we look forward to new innovations in the field from the readers of this book.