Photocured Poly(ε-caprolactone) Nanocomposites as Therapeutic Carriers Fabricated Using Pickering High Internal Phase Emulsion

Abstract

Poly(ε-caprolactone) (PCL)-based materials are widely studied in various morphologies as drug carriers. However, high internal phase emulsion (HIPE)-templated constructs capable of producing porosities >70% facilitating high drug loading have scantly been explored. While various PCL based macromers that have been HIPE-templated, which postpolymerization led to the fabrication of polymerized HIPE (polyHIPE), these HIPEs have been stabilized using surfactants which post removal leads to environmental pollution. Addressing these concerns, liquid photocurable PCL oligomers were synthesized via ring opening polymerization of the ε-caprolactone (CL) monomer using hydroxyethyl methacrylate (HEMA) as an initiator. The optimized PCL oligomer was stabilized within HIPE using modified silica nanoparticles (mSiNP) that were photocured and cross-linked to fabricate PCL-based porous polyHIPEs. The resulting polyHIPEs demonstrated a high porosity of up to 76% along with excellent mechanical strength. The high liquid uptake capacity of polyHIPEs facilitated extremely high tea tree oil (TTO) loading of >100% of the weight of polyHIPE without significantly affecting their mechanical integrity. The release behavior of TTO from the polyHIPE was studied using Weibull and Ritger–Peppas models. Finally, TTO-loaded polyHIPEs demonstrated excellent antimicrobial properties against both Staphylococcus aureus and Escherichia coli irradicating >99% of viable bacterial colonies along with biofilm inhibition over the surface of TTO-loaded polyHIPEs.