The answer is: the focusing method of the matrix glue coating is: use the precooled gun head or pipette to gently suck out the matrix glue and stir it evenly (please replace the gun head or pipette whenever the matrix glue blocks the gun head or pipette).

Matrix glue is extracted from mouse tumor tissue (basement membrane is a layer of matrix membrane on the basal surface of animal epithelial cells) (figure 1). The main components of matrix glue are laminin, type IV collagen and nestin. At the same time, the matrix glue also contains many growth factors, such as epidermal growth factor EFG, platelet-derived growth factor PDGF, nerve growth factor NGF, basic fibroblast growth factor FGF-2, transforming growth factor B-β and insulin-like growth factor ILGF (Vukievic et al. 1992).