Microinjection is a laboratory technique used to introduce substances, such as DNA or proteins, directly into a cell. This method involves using a fine glass needle to inject the material into the cytoplasm or nucleus of the target cell. It is commonly used in genetic engineering and developmental biology to study gene function and create genetically modified organisms. The process requires precise control and is often performed under a microscope. Microinjection is essential for creating transgenic organisms, such as mice or plants, which have altered genetic material. This technique has significantly advanced research in fields like molecular biology and biotechnology.