Microfluidic devices as tools for mimicking the in vivo environment

One of the major branches of microfluidic development is cell engineering. A number of devices for cell cultivation, lysis, single-cell analysis and cell-based toxicity tests have been reported in the literature. The variety of structures that can be created leads to devices more closely mimicking the in vivo environment than classic cell cultures. Studies on this topic will have an effect on the evaluation of methods that can replace animals in biomedical research. The aim of this review is to present latest advancements of "lab-on-a-chip'' for cell cultivation and engineering. The authors focus on the achievements leading to in vivo-like methods. The materials and fabrication methods in silicon, glass, PDMS and other polymers were briefly characterized. Microfluidic devices were applied for mimicking the in vivo environment at various levels of mammalian body organization-from the surroundings of single cells to interactions between functional organs. Solutions for "human-on-a-chip'', perfusion cell cultures, extracellular matrix analogues, microscaffolds, spheroid formation and co-cultures were reviewed in this paper. The presented solutions have the potential to become new cellular models for toxicology, drug development and biomedical research.