Natural stimulus responsive scaffolds/cells for bone tissue engineering : influence of lysozyme upon scaffold degradation and osteogenic differentiation of cultured marrow stromal cells induced by CaP coatings

摘要

This work proposes the use of nonporous, smart, and stimulus responsive chitosan-based scaffolds for bonetissue engineering applications. The overall vision is to use biodegradable scaffolds based on chitosan and starchthat present properties that will be regulated by bone regeneration, with the capability of gradual in situ poreformation. Biomimetic calcium phosphate (CaP) coatings were used as a strategy to incorporate lysozyme at thesurface of chitosan-based materials with the main objective of controlling and tailoring their degradation profileas a function of immersion time. To confirm the concept, degradation tests with a lysozyme concentration similarto that incorporated into CaP chitosan-based scaffolds were used to study the degradation of the scaffolds andthe formation of pores as a function of immersion time. Degradation studies with lysozyme (1.5 g=L) showed theformation of pores, indicating an increase of porosity (*5–55% up to 21 days) resulting in porous threedimensionalstructures with interconnected pores. Additional studies investigated the influence of a CaPbiomimetic coating on osteogenic differentiation of rat marrow stromal cells (MSCs) and showed enhanceddifferentiation of rat MSCs seeded on the CaP-coated chitosan-based scaffolds with lysozyme incorporated.At all culture times, CaP-coated chitosan-based scaffolds with incorporated lysozyme demonstrated greaterosteogenic differentiation of MSCs, bone matrix production, and mineralization as demonstrated by calciumdeposition measurements, compared with controls (uncoated scaffolds). The ability of these CaP-coatedchitosan-based scaffolds with incorporated lysozyme to create an interconnected pore network in situ coupledwith the demonstrated positive effect of these scaffolds upon osteogenic differentiation of MSCs and mineralizedmatrix production illustrates the strong potential of these scaffolds for application in bone tissue engineeringstrategies.