Carrageenan was used to prepare carrageenan films reinforced with chitin nanowhiskers. Atomic force microscopy was used to characterize the morphology and roughness of the films. Structural characterization was performed using X-ray diffraction and Fourier transform infrared spectroscopy. The mechanical properties were assessed by tensile tests. The prepared nanocomposites were used as cell substrate in order to explore their potential biological applications. HeLa cells were seeded on the samples in order to assess their biocompatibility. The preliminary results show good cell proliferation but low cell adhesion, demonstrating a potential application of this novel material as substrate for tumor cell culture. © 2016 Taylor & Francis Group, LLC.