Electrospinning of a sandwich-structured membrane with sustained release capability and long-term anti-inflammatory effects for dental pulp regeneration

Current electrospun membranes used for pulp capping still lack the sustained-release capability and long-term anti-inflammatory effects that are favorable for dental pulp regeneration. In this work, a single-layered poly(lactic acid) (PLA) electrospun membrane loaded with amorphous calcium phosphate (ACP) and aspirin (PLA/ACP/Aspirin membrane, i.e., PAA membrane) is sandwiched between two poly(lactic-co-glycolic acid) (PLGA) electrospun membranes as a novel sandwich-structured PLGA and PAA composite electrospun membrane (PLGA-PAA membrane) to resolve the need for sustained-release design and anti-inflammatory effects. Contact angle measurements indicate that the PLGA-PAA membrane is more hydrophilic than the PAA membrane. An in vitro release study reveals that PLGA membranes coated on PAA membrane could slightly slow down ion release, while significantly prolonging aspirin release. We also co-cultured membranes with dental pulp stem cells (DPSCs) and human monocytic THP-1 cells to evaluate their osteogenic ability and anti-inflammatory effects, respectively. Compared with the PAA membrane, the PLGA-PAA membrane promotes cell adhesion, proliferation, and osteogenic differentiation. A prolonged anti-inflammatory effect of up to 18 days is also observed in the PLGA-PAA group. The results suggest a promising strategy for fabricating an electrospun membrane system with controlled release capabilities and long-term anti-inflammatory effects for use as pulp-capping material for regeneration of the dentin-pulp complex. Graphic abstract