The following article contains critical notes about the possibility of using the observation of biogenic nanoparticles growth (OBNG) methodology to control the living cells’ physiological state during their cultivation in agarose gel and its volume. The methodology’s main idea is to add a low-concentrated silver nitrate solution to the immobilized cells. Cells are able to inhibit the negative effects of silver ions recovering them and forming nanoparticles are being detected by spectrometric methods. It is experimentally proved that the successful use of this methodology for cells state monitoring can only be applicable after choosing a special agarose with a low level of electroendoosmosis (EEO). This type of agarose itself does not lead to the silver nanoparticles formation. All the obtained nanoparticles are only the interaction product of silver nitrate with living cells. It was found that agarose gel layers containing silver nanoparticles prevent the migration of immobilized cells by division.