Modern advances in science in general and in biotechnology in particular have given us the theoretic basis for producing cultured meat. Yet there are still some issues that need resolving before cultured meat is feasible and can become a commercial product available to consumers worldwide.
Much of the knowledge pertaining to cultured meat originates in the medical research of tissue engineering, where many researchers worldwide are trying to create organs for transplantation (livers, hearts, muscles, etc…). Another substantial body of knowledge comes from related research, e.g. the molecular aspects of cells and tissues and the physiological aspects of the human body.
The following is a list of issues science has yet to resolve before we can have commercially viable cultured meat without the use of animal products.
Sustainable growth media:
Cells need a growth medium comprising many substances to nourish them and allow them to divide, differentiate and grow. At present, cells are grown in a medium that contains serum (an animal derivative). There are substitutes for serum, and there are companies that sell serum-free media, but these media are still neither cheap enough nor efficient enough to be a widespread research tool.
This is covered in the overview.
The scientific world lacks knowledge of cells of animals used for food, i.e. cows, chickens, fish, etc., since they are uncommon as scientific research subjects. Characterizing these animals' cells will help understand their needs, their growth and the process of their turning into tissue.
Scaffolding and tissue organization:
Scaffolds are three-dimensional structures on which cells can grow into "3-D", multi-layered tissue. This way of growing tissue differs from standard cell cultures which simply cover the face of a petri dish. Further research is needed to create the ideal edible, sustainable and animal-free scaffold which can facilitate growing animal tissue.
Cell growing is done in bioreactors. Further research is needed to develop bioreactors that are suited for growing large quantities of animal muscle tissue, including ways of supplying nutrients to the cultured tissue, methods of culturing 3-D tissue and ways of recycling nutrients and expelling waste.