Micromechanics and deformation behaviour of porous scaffolds under micro-computed tomography compression
Nissa, Tasneem Un (2026)
2026
Master's Programme in Biomedical Sciences and Engineering
Lääketieteen ja terveysteknologian tiedekunta - Faculty of Medicine and Health Technology
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Hyväksymispäivämäärä
2026-06-08
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202606077102
https://urn.fi/URN:NBN:fi:tuni-202606077102
Tiivistelmä
Porous scaffolds fabricated via emulsion templating offer a promising platform for bone tissue engineering, yet the relationship between scaffold composition, pore architecture, and micromechanical behaviour under physiologically relevant conditions remains incompletely understood. This study investigated the physicochemical and micromechanical properties of polyethylene glycol diacrylate (PEGDA)-based polymerised medium internal phase emulsion (PolyMIPE) scaffolds modified with gellan gum (GG) and gum arabic (GA) at concentrations of 0.1, 0.5, and 1.0% w/v. Seven scaffold formulations were fabricated via thermal crosslinking and characterised through enzymatic and hydrolytic degradation studies, pH-dependent swelling assays, and Fourier transform infrared (FTIR) spectroscopy. Structural and micromechanical behaviour was assessed using micro-computed tomography (micro-CT) compression imaging and rheometer-based cyclic compression testing, conducted under both dry and hydrated (iodine–ethanol) conditions.
All formulations exhibited swelling-dominated behaviour throughout six weeks of degradation, with GG-containing scaffolds showing a modest decline in mass retention from week 4 onwards, indicative of lysozyme-mediated polysaccharide degradation. GA-modified scaffolds displayed comparatively stable degradation profiles, attributed to the compact branched architecture of gum arabic limiting enzyme accessibility. Swelling was pH-dependent across all formulations, with elevated uptake under alkaline conditions. FTIR confirmed successful incorporation of both polysaccharides into the PEGDA matrix.
Micro-CT analysis revealed distinct pore morphologies across formulations: PEG-Basic exhibited elongated, heterogeneous pore channels; PEG-GG 1% produced uniformly distributed spherical macropores; and PEG-GA 1% displayed an open architecture with large, well-separated pores. Under compression, porosity decreased and scaffold height reduced in a formulation-dependent manner, with PEG-GA 1% resisting deformation most strongly, consistent with its highest dry elastic modulus (554 kPa). Structural recovery was near-complete in the wet state (99–103% of initial height) for all formulations, with elastic buckling identified as the dominant deformation mechanism. Pore size distribution analysis confirmed compression-induced narrowing and partial post-relaxation recovery of pore geometry. These findings demonstrate that polysaccharide incorporation meaningfully modulates both the physicochemical and micromechanical behaviour of PEGDA-based PolyMIPE scaffolds, with GG and GA producing distinct and complementary structural outcomes relevant to bone tissue engineering applications.
All formulations exhibited swelling-dominated behaviour throughout six weeks of degradation, with GG-containing scaffolds showing a modest decline in mass retention from week 4 onwards, indicative of lysozyme-mediated polysaccharide degradation. GA-modified scaffolds displayed comparatively stable degradation profiles, attributed to the compact branched architecture of gum arabic limiting enzyme accessibility. Swelling was pH-dependent across all formulations, with elevated uptake under alkaline conditions. FTIR confirmed successful incorporation of both polysaccharides into the PEGDA matrix.
Micro-CT analysis revealed distinct pore morphologies across formulations: PEG-Basic exhibited elongated, heterogeneous pore channels; PEG-GG 1% produced uniformly distributed spherical macropores; and PEG-GA 1% displayed an open architecture with large, well-separated pores. Under compression, porosity decreased and scaffold height reduced in a formulation-dependent manner, with PEG-GA 1% resisting deformation most strongly, consistent with its highest dry elastic modulus (554 kPa). Structural recovery was near-complete in the wet state (99–103% of initial height) for all formulations, with elastic buckling identified as the dominant deformation mechanism. Pore size distribution analysis confirmed compression-induced narrowing and partial post-relaxation recovery of pore geometry. These findings demonstrate that polysaccharide incorporation meaningfully modulates both the physicochemical and micromechanical behaviour of PEGDA-based PolyMIPE scaffolds, with GG and GA producing distinct and complementary structural outcomes relevant to bone tissue engineering applications.