Dual-scale polymeric constructs as scaffolds for tissue engineering using biodegradable polyester and biopolymers

Abstract

The aim of this research activity is developing a dual-scale scaffolds consisting of three-dimensional (3D) constructs of aligned biodegradable polyester Poly (lactid acid) (PLA) microfilaments and electrospun nano-fibers of poly(µ-caprolactone) (PCL) and Poly(lactic acid) (PLA) or combination of both. PLA 3D constructs will be composed by layers of deposed micro-sized filaments at different angles lay-down pattern (orientation: 36º, 40º, 56º, 90º and 120º) with a diameter less than 2mm and different number of layers. These microfilaments will be produced using a melt extrusion-based additive manufacturing technique. PCL and PLA electrospun nanofibers with a diameter around 1 ¼m or less will be collected by electrospinning technique in different ways: (a) on top (and/or bottom) of the PLA 3D constructs with different thicknesses; or (b) the possibilities of introduce between layers these electrospun fibers (layer by layer). As is well known, the fibers obtained by electrospinning techniques biomimetic the extracellular matrix, and may allow to be more effective the process-diffusion during cell proliferation within the 3D array because they can also adjust the pore size and prevent that many cells can not adhere effectively to the microfilaments of the scaffold obtained by extrusion. This dual-scale 3D construct system, not only can also combine scaffolds obtained electrospun PCL and PLA (or conversely), but may also be carried structures by coating these scaffolds using biopolymers such as alginate or chitosan. Furthermore, nanoparticles from these biopolymers -loaded with drugs or not-, could be incorporated both into the microfibers obtained by extrusion as well as in the nanofibers obtained by electrospinning (combination including both drugs and hydroxyapatite can be considered to be incorporated in these systems). It is also of great interest to start hydrolytic biodegradation studies of these systems and to verify how the processing variables for these combined systems (different angles deposition, diameters and layers, and deposition temperature of microfilaments during extrusion, and also the orientation of electrospun fibers) may influence the hydrolytic process (to be more or less slow), which also will define the type of tissue where that could be used these combine system. (AU)