###### Abstract
The fundamental concept is similar to that of DLP, excepting the use of an oxygen-permeable window instead of a glass window. This is responsible for the creation of a \"dead zone\" between the window and the printed part, where photopolymerization is inhibited and a very thin layer of resin remains uncured. As a result, the resolution of the printed object increases and the risk of printing failure due to peeling forces decreases [11]. Two-photon polymerization uses the two-photon absorption of NIR light to excite the photoinitiator in a monomer solution at the focal spot only, initiating the polymerization in a very small volume called \"voxel\" [13]. By using this technology, the material is no longer deposited in a \"layer-by-layer\" manner, and the fabrication of complex 3D microstructures becomes possible. Unfortunately, the toxicity of many feedstock materials limits the use of 2 PP for biological applications [14]. Moreover, the equipment is much more expensive than others based on photopolymerization. Herein, attention is paid to SLA technology, for its excellent abilities to print complex 3D ceramic (based on special composite resins and heat treatment postprocessing) and polymer structures, for biomedical field with high accuracy, high printing speed and low costs. In particular, SLA has been already applied to fabricate 3D structured graphene-based polymer composites. The materials suitable for 3D printing have to feature facile processability and stability during storage, along with cost-effectiveness and abundance of the raw materials required for industrial demands. Materials for SLA are clear resins, resins with additives and resins with added nano/micro functional particles. In general, the addition of fillers in the SLA resin leads to a stiffer and stronger fabricated structure than additive-free polymer resin. Except for the mechanical properties' improvement, electrical conductivity can be achieved by the addition of carbon-based nanofillers, such as carbon nanotubes, carbon nanofiber, carbon-black, and graphene have been added to fabricate composites [15]. The graphene family is considered an important nanofillers as it increases the stiffness, conductivity [16] and, in some cases, cytocompatibility. Graphene and its derivatives represent the central point for a wide range of applications and technical solutions. Though they were initially used as filler in composite polymeric materials due to their high surface area and excellent mechanical properties [17; 18; 19; 20], more and more applications started to also value the high electrical conductivity or potential of these species for separative or other advanced applications. In the field of sensors and biosensors, graphene is one of the most important candidates. With a high ability for adsorbing, even gas molecules can be used with minimum manufacturing stages for obtaining industrial sensors [21; 22]. Energy storage devices based on graphene can be obtained under a wide range of products such as fuel cells, batteries or even solar cells [23]. One of the most fascinating fields for electronic applications is represented by the biosensors due to the high versatility for functionalization reactions and the possibility to immobilize surface enzymes, proteins or other active biological chemical species and thus, the potential uses are practical unlimited [24]. In the field of environmental protection, the adsorption of metal oxides can lead to a lot of catalysis applications for the degradation of organic substances from water [25] or directly for water filtration through composite membranes with graphene, in which the filler act as a molecular sieve [26]. Latest applications in the medical field include tissue engineering for bone repair by favouriting osteogenesis [27], soft tissues regeneration by active behaviour in cells differentiation, direct or via functionalization [28], or even haemodialysis using composite membranes with functionalized graphene for removal of heavy metal ions from blood in case of intoxations [29; 30; 31].