Keratinocyte biocompatibility, antibacterial and antioxidant properties of porous coacervate phosphate glass fibres and powders loaded with cerium and clove oil: a comparative study

Abstract

Porous biomaterials offer significant advantages in tissue engineering such as the promotion of cellular attachment and enhanced flow of fluids. Here we present a versatile, sustainable and low-cost manufacturing technology for the production of porous phosphate-based glass fibres (PGFs) and powders (PGPs) unloaded or loaded with cerium ions (Ce = 0, 0.1, 0.2 and 0.4 atomic %). A polyphosphate coacervate gel combined with the porogen Pluronic 123 (P123) was used as precursor material for manufacturing PGFs (via electrospinning) and PGPs (via drying). Porosity was achieved by removing P123 via calcination at 300 °C. The release of cerium ions from PGPs and PGFs resulted in good antibacterial activity against the bacterium E. coli. The oxidation state of cerium ions and their ratio was identified via X-ray Photoelectron Spectroscopy (XPS). Successful direct seeding of the most common type of skin cells, keratinocyte (HaCaTs) on PGFs was demonstrated for the first time via live cell staining. PGFs exhibited excellent cytocompatibility, both when directly seeded onto HaCaTs and when presented as dissolution products, demonstrating the great potential of PGFs for wound healing applications. In order to enhance the antibacterial and antioxidant properties, PGFs and PGPs were embedded with the natural antioxidant compound clove oil (clv). The antioxidant capacity was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and TPC (total phenolic content) assays. PGFs containing 0.4 atomic % of Ce loaded with clv demonstrated strong antioxidant activity, with DPPH scavenging reaching approximately 87 % and phenolic content measured at around 25 mg gallic acid (GAE) g⁻¹. Furthermore, the combined effect of Ce ions and clv on antioxidant performance and antibacterial activity against E. coli was investigated, revealing notable enhancement in both radical scavenging and bacterial growth reduction.