Preparation (Pulling) of Needles for Gene Delivery by Microinjection
This protocol was adapted from “Gene Delivery by Direct Injection and Facilitation of Expression by Mechanical Stretch,” Chapter 4, in Live Cell Imaging (eds. Goldman and Spector). Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA, 2005.INTRODUCTION
This protocol contains methods for pulling microinjection needles using two different models of pipette pullers. The advantage of pulling needles in the laboratory is that a variety of different needle types can be pulled, depending on the samples and cells being injected. An added advantage is cost; once a pipette puller has been purchased, boxes of glass capillaries are inexpensive compared to premade microinjection needles. The advantages to buying preformed and sterilized needles include increased uniformity of needles from one to another, ease of use, high quality, and not having to invest in a pipette puller. The pipette puller models described in this article are the Flaming/Brown Pipette Puller Model P-97 (Sutter) and the PUL-1 Micropipette Puller (World Precision Instruments). The PUL-1 instrument is the less expensive of the two, but it requires more user input, and it cannot be used to pull Femtotip-like microinjection pipettes.
