Quantum dots-labeled polymeric scaffolds for <i>in vivo</i> tracking of degradation and tissue formation.

Abstract

The inevitable gap between <i>in vitro</i> and <i>in vivo</i> degradation rate of biomaterials has been a challenging factor in the optimal designing of scaffold's degradation to be balanced with new tissue formation. To enable non-/minimum-invasive tracking of <i>in vivo</i> scaffold degradation, chemical modifications have been applied to label polymers with fluorescent dyes. However, the previous approaches may have limited expandability due to complicated synthesis processes. Here, we introduce a simple and efficient method to fluorescence labeling of polymeric scaffolds via blending with near-infrared (NIR) quantum dots (QDs), semiconductor nanocrystals with superior optical properties. QDs-labeled, 3D-printed PCL scaffolds showed promising efficiency and reliability in quantitative measurement of degradation using a custom-built fiber-optic imaging modality. Furthermore, QDs-PCL scaffolds showed neither cytotoxicity nor secondary labeling of adjacent cells. QDs-PCL scaffolds also supported the engineering of fibrous, cartilaginous, and osteogenic tissues from mesenchymal stem/progenitor cells (MSCs). In addition, QDs-PCL enabled a distinction between newly forming tissue and the remaining mass of scaffolds through multi-channel imaging. Thus, our findings suggest a simple and efficient QDs-labeling of PCL scaffolds and minimally invasive imaging modality that shows significant potential to enable <i>in vivo</i> tracking of scaffold degradation as well as new tissue formation.