Advancing Sterilization of Medical Implant Polymers: Novel Low-Temperature Deep-vacuum Vaporized H2O2 Technology Surpasses Current Methods

Purpose
To develop a deep vacuum vaporized hydrogen peroxide (VH₂O₂) sterilization method capable of preserving the structural and functional integrity of biocompatible polymeric electrospun mats usable as advanced biocompatible medical implants and devices, with particular focus on the influence of vacuum level during treatment.

Methodology
Electrospun mats made of poly-L-lactide-co-glycolide (PLGA), poly-L-lactide-co-ε-caprolactone (PLC), and thermoplastic polyurethane (TPU) were prepared and sterilized with VH₂O₂ under low-vacuum (LV, 10 mbar) and high-vacuum (HV, 2 mbar) conditions at 20–50 °C. Scanning electron microscopy (SEM) assessed fiber morphology and pore area, contact angle measurements evaluated surface wettability, Fourier-transform infrared spectroscopy (FTIR) detected chemical modifications, and gel permeation chromatography (GPC) analyzed weight-average molecular weight (Mw) and polydispersity index (PI).

Results
HV sterilization caused fiber compression across all polymers, increasing fiber diameter and reducing pore area. LV sterilization conditions prevented morphological changes in TPU and PLC, while PLGA remained sensitive under both vacuum levels. PLGA also exhibited increased hydrophilicity due to surface reorganization and transition from Cassie–Baxter to Wenzel-type wetting. FTIR showed no chemical changes, and GPC confirmed stable Mw and PI for all tested materials (PLGA: 25–27 kDa; PLC: 16–18 kDa; TPU: 23–25 kDa).

Conclusion
Deep vacuum VH₂O₂ sterilization at room temperature is feasible, with vacuum level critical for maintaining scaffold integrity. LV sterilization effectively preserves morphology in PLC and TPU, while HV is also reliable for less sensitive polymers. Chemical and molecular properties remain unaffected, supporting VH₂O₂ sterilization as a gentle and effective promising method for implantable textile-based biomaterials.