Overview of Cell Models: From Organs Cultured in a Petri Dish to Organs-on-Chips

Abstract

In this review, we tried to elucidate the origin and development of different animal and human cell culture methodologies used to evaluate the effects of various factors and substances in vitro. Organ cultures and conventional two-dimensional cultures of dissociated cells of various types, such as primary, tumor, induced pluripotent, stem, etc., have their advantages and drawbacks but usually do not represent accurate models for studying biological processes that take place in living organisms. Nowadays, high-throughput cell assays on the basis of various methods of signal detection (optical utilizing colorimetric, luminescent and fluorescent methods of detection, and electrochemical) are widely used at early stages of drug development for selection of the most active compounds and evaluation of their cytotoxic effects. The use of animals as models for drug testing is being criticized because of the lack of correlation between the results obtained in studies on them and on humans, and also because of the high cost and ethical issues. Therefore, much effort is put to create models based on human cells. This is how cultures emerged that utilize a three-dimensional network to simulate the architecture of tissues in vivo, and then so-called organs-on-chips—microfluidic microfabricated devices combining several types of cells—that replicate physical and chemical parameters of the microenvironment of cells in living organisms. In summary, experimental cell models have come a long way from the whole organs cultivated in a growth medium to almost complete reconstruction of organs in vitro based on the cutting-edge engineering approach with the use of different cell types. This currently enables one to replicate complex biological processes and study the influence of different substances and factors on them more successfully.