Profile: NuCollagen LLC manufacturers pure, natural collagen for stem cell media needs. Collagen is the most abundant human protein and the main component of connective tissues. It is characterized as a structural protein in function, the scaffolding of human bodies. Collagen is naturally present in skin and in most body tissues to include blood vessels & cartilage. It is responsible for skin tone, flexibility and elasticity. Induced pluripotent stem cells (iPSCs) are adult cells that have been genetically reprogrammed to an embryonic stem cell--like state. This is done by forcing them to express genes and factors important for maintaining the defining properties of embryonic stem cells.