Dextran-Polydopamine Dual Coating on 3D-Printed Polycaprolactone Scaffolds as a Potential Biofunctionalization Platform for Bone Tissue Engineering

Three-dimensional (3D) printing has paved the way for
the precision
manufacturing of patient-specific scaffolds. While personalized 3D-printed
bone scaffolds are already in the clinic, further attempts to combine
biofunctionalization and drug delivery with these scaffolds are of
great interest to improve tissue regeneration and reduce recovery
time. This study investigated the dextran-polydopamine (PDA) dual-coated
3D-printed polycaprolactone (PCL) scaffolds as a potential biofunctionalization
platform, which will enable the design of more advanced coating systems.
Despite PCL being one of the most well-established biomaterials used
in manufacturing bone scaffolds, surface modification is essential
for its application due to its hydrophobic surface and lack of osteogenic
properties. PDA is a bioinspired synthetic polymer, known for its
convenient coating strategy, superior osteogenicity, and ability to
graft secondary biofunctionalization motifs. However, modifying the
surface of PCL with PDA results in aggregates of PDA nanoparticles
rather than forming a homogeneous coating layer. Here, dextran was
introduced as a dual coating deposited as a thin layer, which further
assists cell adhesion and proliferation. Dextran is a biomedical macromolecule
with a long history in medicine, which can be used as a drug delivery
carrier in various forms, and the focus of this study was to investigate
the intricate interplay between dextran and PDA as a dual coating
applied to 3D-printed PCL scaffolds, via microstructural, topographical,
chemical, and mechanical validation. A series of cell studies using
osteoblast-like MG-63 cells was conducted, and it has been confirmed
that dextran can be introduced to the PDA-modified PCL scaffold while
maintaining the maximum scaffold and cell interaction. Consequently,
the present results suggest that the dextran-PDA dual coating offers
a promising biofunctionalization platform for designing more complex
systems involving dextran-based drug delivery, aimed at application
in bone tissue engineering.