text: Standard monolayer cell culturing on tissue culture plastic has notably improved the understanding of basic cell biology, but it does not replicate the complex 3D architecture of in vivo tissue, and it can significantly modify cell properties. This often compromises experiments in basic life science, leads to misleading drug-screening results on efficacy and toxicity, and produces cells that may lack the characteristics needed for developing tissue regeneration therapies.
  The future of cell culturing for fundamental studies and biomedical applications lies in the creation of multicellular structure and organization in three dimensions. Many schemes for 3D culturing are being developed or marketed, such as bio-reactors or protein-based gel environments.
  A 3D cell culturing system known as the Bio-Assembler uses biocompatible polymer-based reagents to deliver magnetic nanoparticles to individual cells so that an applied magnetic driver can levitate cells off the bottom of the cell culture dish and rapidly bring cells together near the air-liquid interface. This initiates cell-cell interactions in the absence of any artificial surface or matrix. Magnetic fields are designed to rapidly form 3D multicellular structures in as little as a few hours, including expression of extracellular matrix proteins. The matrix, protein expression, and response to exogenous agents of resulting tissue show great similarity to in vivo results.