A photosensitive composition activatable by multiphoton absorption usable for the fabrication of a three-dimensional structure which is biodegradable and/or biocompatible and/or bioresorbable. This structure is usable as a matrix for cell culture. The photosensitive composition comprises: gelatin, collagen, a water-soluble photoinitiator, able to be excited by several photons and capable of generating singlet oxygen, optionally a cell adhesion promoter, and water. A process for preparing the photosensitive composition, a process for preparing a three-dimensional structure from the photosensitive composition, the three-dimensional structure obtained by this preparation process and a matrix for cell culture comprising this structure.