Abstract Multicellular tumor spheroids embedded in collagen I matrices are common in vitro systems for the study of solid tumors that reflect the physiological environment and complexities of the in vivo environment. While collagen I environments are physiologically relevant and permissive of cell invasion. studying spheroids in such hydrogels presents challenges to key analytical ass... https://www.farmingtondepotgallery.com/product-category/balloons-giant-foil-letters/