Hybrid Tissue Engineering Scaffolds by Combination of Three Dimensional Printing and Cell Photoencapsulation

Abstract

Threedimensional (3D) printing offers versatile possibilities for adapting the structural parameters of tissue engineering scaffolds. However, it is also essential to develop procedures allowing efficient cell seeding independent of scaffold geometry and pore size. The aim of this study was to establish a method for seeding the scaffolds using photopolymerizable cellladen hydrogels. The latter facilitates convenient preparation, and handling of cell suspension, while distributing the hydrogel precursor throughout the pores, before it is crosslinked with light. In addition, encapsulation of living cells within hydrogels can produce constructs with high initial cell loading and intimate cellmatrix contact, similar to that of the natural extracellular matrix (ECM). Three dimensional scaffolds were produced from poly(lactic) acid (PLA) by means of fused deposition modeling. A solution of methacrylamidemodified gelatin (GelMOD) in cell culture medium containing photoinitiator LiTPOL was used as a hydrogel precursor. Being an enzymatically degradable derivative of natural collagen, gelatinbased matrices are biomimetic and potentially support the process of cellinduced remodeling. Preosteoblast cells MC3T3E1 at a density of 10 أ— 106 cells per 1 mL were used for testing the seeding procedure and cell proliferation studies. Obtained results indicate that produced constructs support cell survival and proliferation over extended duration of our experiment. The established twostep approach for scaffold seeding with the cells is simple, rapid, and is shown to be highly reproducible. Furthermore, it enables precise control of the initial cell density, while yielding their uniform distribution throughout the scaffold. Such hybrid tissue engineering constructs merge the advantages of rigid 3D printed constructs with the soft hydrogel matrix, potentially mimicking the process of ECM remodeling.