Abstract <p>This work examines the mechanical properties of a transformable fibrous nitrocellulose matrix that can be used as a cell carrier in bioartificial cell systems. To measure the mechanical properties of fibrous matrices, a device was developed and constructed that can be used to conduct studies of a variety of matrices, which are the basis for populating cell cultures during the formation of artificial organs and tissues. The effect of reducing the mechanical stress and Young’s modulus of a wet nitrocellulose matrix compared to a dry one at the same relative deformation was discovered experimentally, which is due to the porosity of the matrix and fluid friction between the fibers. In the theoretical description of the mechanical properties, 2-, 3-, 5-, and 9-parametric Mooney–Rivlin hyperelastic models were used. Their parameters were calculated for both a dry and a wet nitrocellulose matrix based on the experimental data obtained, and a comparative analysis of the experimental data and theoretical dependences of mechanical stress and Young’s modulus were carried out. The results obtained can be used in the future for a detailed study of the cell-matrix interaction, which may make it possible to develop modern new generation biomaterials with physical properties close to living tissue for use in regenerative medicine.</p>