Comparative Structural and Functional Analysis of Micronized Collagen-Based Scaffolds

Micronized collagen-based bioscaffolds are increasingly used in clinical applications for wound repair and soft tissue regeneration. This study compared the structural properties of four different commercially available micronized products derived from either reconstituted collagen (pRC), urinary bladder matrix (pUBM), or ovine forestomach matrix (mOFM, mOFMµ). The test articles were characterized by laser diffraction analysis, scanning electron microscopy (SEM), micro-computed tomography (micro-CT), packing density, differential scanning calorimetry, rheometry, proteolytic stability, agarose gel electrophoresis, and blood clotting index. Particle size and surface morphology, assessed by laser diffraction, SEM, and micro-CT, revealed marked differences in particle size, shape, and aggregation. Packing density ranged from 80.3 ± 2.7 mg/cm³ (mOFM) to 484.7 ± 17.8 mg/cm³ (pRC). Thermal analysis demonstrated the native structure of the OFM-based test articles (T_m, 59.80 ± 0.11°C and 58.15 ± 0.15°C) relative to pUBM and pRC (T_m, 41.06 ± 0.06°C and 40.59 ± 0.23°C). Rheological testing revealed that mOFM and mOFMµ had increased cohesive energy, indicating better mechanical resilience when the micronized materials were rehydrated to form a paste. The OFM-based test articles exhibited the greatest resistance to proteolytic digestion (T_1/2, 12.730 ± 1.232 and 5.759 ± 0.1296). All the test articles, except for the reconstituted collagen product, demonstrated hemostasis in whole blood. Micronized reconstituted collagen showed immediate dissolution and no fluid absorption, hemostasis, or resistance to proteolytic digestion, whereas micronized OFM showed the greatest proteolytic stability and packing density. Substantial differences among the micronized bioscaffolds were revealed from the analysis, most likely due to their different source materials and manufacturing processes. Careful consideration of these parameters is warranted when selecting a micronized product for soft tissue applications.