Hollow polymeric fibers are used in many applications in the field of biomedicine, being traditionally employed as filters for dialysis, but also as substrates for the cultivation of tissues and cells, as well as the controlled release of drugs. These applications present very demanding requirements, the fibers must be biocompatible, have a controlled pore size, excellent connectivity between the pores and appropriate mechanical properties to fulfil their function. These requirements limit the range of polymers that can be used and require the use of complex and expensive manufacturing techniques.
In this work, we developed a new generation of hollow fibers from conventional fibers of various biocompatible polymers (PCL, PMMA, etc.), following a simple modification process with low environmental impact, and explored their potential biomedical applications (tissue regeneration, drug release, etc.).
The modification of the fibers, that is to say, the production of the internal porosity, was carried out by foaming by gas dissolution foaming, an environmentally friendly process, which was used for the first time for the development of porosity in polymeric fibers. Traditionally this process has been limited to bulk pieces with thicknesses of several millimeters, or required complex constraining metallic molds in the case of films with a thickness of hundreds of microns. However, herein we overcame this limitation through the appropriate use of gas diffusion barriers and the optimization of the parameters of the foaming process, producing for the first time foamed hollow polymeric fibers with controlled diameters of few microns.