Аннотация:The toxicity of polyethylenimine-based sorbents and their extracts was evaluated, and their effecton the bioluminescence of Photobacterium phosphoreum photobacteria was studied. These test bacteria arecommonly used as objects to evaluate the toxicity of various materials. The analyzed materials were synthesized via polyethylenimine (PEI) cross-linking with diethylene glycol diglycidyl ether (DGDE) at mass contents of the latter of 1.9–120.0% with subsequent freezing. It was found that the degree of luminescence inhibition in P. phosphoreum cells depended on the PEI/DGDE ratio in the sorbent. Sorbents with a high DGDEcontent (60–120%) did not affect the cell luminescence activity, while those with a lower percentage of thecross-linker (0.9–30%) exhibited a pronounced inhibitory effect on luminescence of photobacteria accordingto the data obtained with the standard biotesting method. It was also established that the inhibitory effect ofsorbents with a reduced DGDE percentage (<30%) in a phosphate buffer was significantly lower than that insalt solutions. Water and ethanol extracts of sorbents with a DGDE mass proportion of more than 15% didnot significantly inhibit the luminescence of P. phosphoreum in 1 h of incubation. The immobilization ofP. phosphoreum cells on the surface and internal parts of the studied sorbents was observed via scanning electron microscopy