Cell culture is a complex process by which cells in the most basic unit of human body are continuously grown under controlled conditions, generally outside of their natural environment, or the cells are developed into other cells having different properties by adding a specific growth factor thereto. In terms of modern science, a cell culture technology has been placed in the field of basic essentials, and in particular, in the field of medical engineering, the cell culture technology has been widely used in judging whether or not a license for a drug is approved through cytotoxicity assessment using a preclinical test and has been also applied to researches for finding the mechanism of diseases.
As cells show different shapes and characteristics depending on derived species or the parts of tissues, the cells have different types of metabolites generated through metabolism. In particular, in the case of stem cells which can be differentiated into various tissue cells, there are specific metabolites depending on differentiated cell types.
In general, most of experiments for ascertaining whether or not cells are differentiated are performed in such a way as to observe a result obtained from reaction to a reagent, and a staining, PCR (Polymerase Chain Reaction) method and the like fall into such a way. Since the described methods are invasive methods in which cells cannot be reused after reaction, in order to verify reproducibility through repeated experiments using cells, a large number of samples are needed for one experiment, and thus, the costs required for one experiment are increased. Also, the existing experimental method should endure an error generated by applying the experiment to different samples, and due to this, it has a limit of the reduction in reproducibility and reliability of experimental results.
A magnetic resonance spectroscopy (hereinafter referred to as ‘MRS’ or ‘NMR’) and a magnetic resonance imaging (hereinafter referred to as ‘MRI’) are techniques capable of noninvasively and nondestructively measuring bio-signals, and in the current medical field, the MRI is drawing attention as a diagnostic equipment thanks to a high soft tissue contrast and various contrast parameters of the MRI. However, the MRI and MRS have low sensitivity in regard to a volume, and thus show low resolution with respect to small objects of less than a certain thickness. In order to overcome this problem, an MR machine of a higher magnetic field is needed, but even the MR machine is difficult to be applied to cells in the unit of μm.