A Novel Glycosaminoglycan Mimetic for Chemokine Hydrogel Functionalization

Objectives: Humans, unlike salamanders, lack the ability to regenerate infected tissues, with regenerative capacity decreasing post-birth alongside immune system development. However, tissue repair, regeneration, and immune system-guiding cells can be modulated. This study assesses the effects of the chemokine-binding and antimicrobial polymer, chlorite-oxidized oxyamylose (COAM), on chemokine delivery for dental pulp repair and regeneration.
Methods: Chemokine (SDF-1/CXCL12) binding to COAM was analyzed using gel filtration chromatography. COAM's glycosaminoglycan mimetic properties were evaluated via surface plasmon resonance (SPR). Chemokine release from fibrin hydrogels was assessed using enzyme-linked immunosorbent assay (ELISA). The immunophenotype of dental pulp stromal cells (hDPSCs) encapsulated in 3D fibrin hydrogels was examined with flow cytometry analysis (FACS). CXCR4⁺ populations within hDPSCs were investigated using Western blot and FACS. The influence of encapsulation and the presence of COAM and SDF-1/CXCL12 on hDPSC proliferation was evaluated by FACS. An ex-vivo tooth model was employed to study dental pulp reactions to functionalized hydrogels.
Results: Gel chromatography and SPR revealed that COAM forms a strong binding complex with SDF-1/CXCL12, exhibiting a higher affinity than heparin sulfate. The formation of this binding complex influenced SDF-1/CXCL12 release patterns from fibrin hydrogels. hDPSCs maintained their phenotype after 14 days of encapsulation, and COAM and SDF-1/CXCL12 presence did not impact encapsulated hDPSC proliferation patterns.
Conclusions: COAM formed a binding complex with SDF-1/CXCL12, delaying release from fibrin hydrogels and demonstrating greater efficiency than heparin sulfate. COAM may be a promising strategy for hydrogel functionalization with chemokines for immunomodulated dental pulp regeneration.