MALC, a novel microinjection method for loading of macromolecules into cultured neurons

Microinjection is one of the most useful and important methods in cellular neurobiology. However, direct insertion and retraction of a capillary produce physical stresses inside cells that make it difficult to apply on small and fragile cells, especially the central nervous system (CNS) neurons. In this study, we developed a novel method called MALC (microinjection method assisted with laser activated chromophore) to avoid this disadvantage of the conventional method. In MALC, a capillary is just attached on cell surface, and combination of a newly developed photosensitizer with a laser pointing system makes the plasma membrane permeable to molecules. This novel method can expand the application of the microinjection method and realize molecular manipulations inside CNS neurons.