Melt-spun Polycaprolactone Filaments Incorporating Biodegradable Microcapsules for Biomedical Textile Applications

Abstract This study investigates the fabrication and characterization of bioactive melt-spun poly(ε-caprolactone) (PCL) filaments incorporated with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) microcapsules containing Momordica charantia L. extract for biomedical textile applications. Utilizing the inherently low melting temperature of the PCL polymer, the structural and functional stability of the temperature-sensitive microcapsules was successfully preserved during compound extrusion and continuous filament spinning. Morphological analyses revealed that while the microcapsules induced some surface protrusions and localized agglomerations, the cross-sectional uniformity of the composite fibres remained entirely uncompromised. Furthermore, thermal and crystallographic evaluations confirmed that microcapsule incorporation did not significantly alter the inherent thermal behaviour of the PCL polymer, preserving its typical α-form crystalline structure across all samples. Crucially, quantitative antibacterial assays demonstrated bioactivity against Staphylococcus aureus and Escherichia coli. The composite fibres exhibited higher inhibition rates against Gram-positive S. aureus, which is attributed to the higher permeability of its peptidoglycan layer to the hydrophobic plant extract compared to Gram-negative bacteria. Moreover, depending on the spatial distribution of the microcapsules within the fibre architecture (surface-proximal vs. matrix-embedded), the system demonstrated tunable antibacterial efficacy, providing both rapid contact-based inhibition and potential for sustained bioactivity. These concrete findings establish that microcapsule-doped, melt-spun PCL filaments offer an effective, highly adaptable platform for the design of biomedical textile materials.