A fibroblast is a large, flat, spindle-shaped cell that is extremely important for wound healing since it produces tropocollagen, the precursor of collagen. This cell type also produces glycosaminoglycans, fibers, and glycoproteins that together comprise the extracellular matrix of connective tissue. Within the branched cytoplasm of a fibroblast, an elliptical, flat nucleus with one or more nucleoli is typically found. Active and inactive fibroblasts can be differentiated visually by their rough endoplasmic reticulum, the membranous system being much more extensive in active cells. Inactive fibroblasts are also usually smaller in size than their active counterparts.

Alexa Fluor 568 conjugated to phalloidin was utilized to label the 3T3 cell culture presented in the digital image above for intracellular filamentous actin, while DAPI was used to target DNA in the cell nuclei. The cells were simultaneously stained with Alexa Fluor 488 conjugated to concanavalin A, a lectin displaying very high affinity for specific carbohydrate residues in glycoproteins, enzymes, and cell membranes. Images were recorded in grayscale with a QImaging Retiga Fast-EXi camera system coupled to an Olympus BX-51 microscope equipped with bandpass emission fluorescence filter optical blocks provided by Omega Optical. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.