Knockout tissue models: Targeted gene disruption in three dimensions

The use of animal studies in scientific research is increasing, mostly attributed to the rising requirement for genetically modified animals. In 2012, 4.11 million animal procedures were conducted within the UK, the majority of which involved genetically modified animals; a first since records began. Although animal models bring clear scientific insight, they have their limitations and alternative research methods are actively sought. The development of new targeted gene disruption technologies, such as transcription activatorlike effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR), combined with innovative 3D human cell culture methods can provide an attractive in vitro alternative.