## 1 Introduction  
The regeneration and repair of biological tissues usually require a temporal or permanent support to provide at least structural and mechanical properties. Tissue engineering appears as a new research discipline [1; 2; 3] that is addressed to develop new materials with appropriate properties and features that can also improve their final performance with additional functions. Efforts are mainly focused on accelerating the regeneration and reparation of tissues, to guide cell growth [4], to increase the biodegradability of temporal supports, to decrease cytotoxicity [5; 6], to produce nanocomposites reinforced with particles or fibers in order to improve adhesion and cell proliferation [7; 8; 9], to incorporate growth factors and other bioactive agents in order to stimulate cell growth [10; 11], to give an antimicrobial response or other effects such as radical scavenging [12], and finally, to develop materials with electroconductive properties that make feasible an electrical stimulation or a controlled drug release [13]. Tissue engineering has developed the so-called scaffolds, which are biomaterials that mimic the extracellular matrix of tissues. Scaffolds are usually porous supports with a three-dimensional structure that allows increasing the number of adhered cells and the cell growth [14]. Furthermore, porous scaffolds may also enhance cell transit and diffusion of nutrients and growth factors [15; 16]. Biodegradable polymers are usually employed when scaffolds should have a temporary function and act as templates for tissue repair and regeneration. Extensive reviews have been focused on the selection of appropriate polymeric materials since degradation rate and maintenance of properties should be in agreement with the time required for tissue regeneration [17; 18; 19]. Scaffolds can also be considered as drug releasing systems since the polymer matrix can be loaded with the appropriate active agents. Scaffolds increase their surface due to their porous structure and therefore the amount of drug released could be tuned depending on this surface. In most cases, scaffolds have been developed as temporary supports based on biodegradable materials, having some of the above indicated specific properties (e.g., antibacterial activity). Triclosan (TCS), for example, is usually employed as biocide in both home and hospital settings for disinfection. TCS has a clear hydrophobic character and basically acts as an inhibitor of the bacterial lipid biosynthesis [20]. There are several methods to obtain a porous polymeric scaffold; some of them can directly generate the pores while in other cases a secondary treatment is needed. Deposition and assembly of micro/nanofibers is a common one step process. These meshes can be produced by the bonding of different fibers, where some of them (with lower melting point) act as a reticulation point, or by electrospinning. The binding process is simpler but the porosity grade is not under such accurate control as could be achieved through electrospinning [21; 22]. Most of direct processes developed for scaffold production are limited to a laboratory scale and are not widely applied in the industrial field. By contrast, indirect procedures are more common in big mass production and also they allow a fabrication with the desired final shape [23]. Conventional industrial procedures, such as extrusion or injection can be applied when are combined with the salt leaching technique. In this case, the polymer is mixed with a water-soluble salt and then molded. Porosity is created after removing the salt by water immersion. Porous size and density can be accurately controlled through the selection of both particle size and the incorporated amount of salt [24; 25]. Nowadays, there is a market demand for high resolution scaffolds that are able to produce shape profiles with nanosized ending to mimic fissures and textures of naturally occurring tissues. Despite the fact that 3D printing can reach this scale with high accurate ending, it is still costly for mass production [26; 27].