Modular polylactic acid microparticle-based scaffolds prepared via microfluidic emulsion/solvent displacement process: Fabrication, characterization, and in vitro mesenchymal stem cells interaction study

The present study reports a novel approach for the design and fabrication of polylactic acid (PLA) microparticle- based scaffolds with microstructural properties suitable for bone and cartilage regeneration. Macroporous PLA scaffolds with controlled shape were fabricated by means of a semicon- tinuous process involving (1) microfluidic emulsification of a PLA/ethyl lactate solution (5% w/v) in a span 80/paraffin oil so- lution (3% v/v) followed by (2) particles coagulation/assembly in an acetone/water solution for the development of a continu- ous matrix. Porous scaffolds prepared from particles with monomodal or bimodal size distribution, overall porosity ranges from 93 to 96%, interparticles porosity from 41 to 54%, and static compression moduli from 0.3 to 1.4 MPa were man- ufactured by means of flow rate modulation of of the continu- ous phase during emulsion. The biological response of the scaffolds was assessed in vitro by using bone marrow-derived rat mesenchymal stem cells (MSCs). The results demonstrated the ability of the scaffolds to support the extensive and uni- form three-dimensional adhesion, colonization, and prolifera- tion of MSCs within the entire construct