Biology subjects

Marchiori, G.

Publications and source records attributed to Marchiori, G..

3 recordsLinked to original sources

bioRxiv2026

Highlighting strain rate dependent vibrational behavior of electrospun bundles for tendon/ligament and enthesis fascicle tissue regeneration

Enthesis tissue engineering aims to develop scaffolds that replicate the mechanical and structural gradients of the tendon/ligament-bone interface. Among the different biofabrication techniques, electrospinning is surely one of the most promising to fabricate morpho-mechanically relevant enthesis fascicle-inspired scaffolds. An interesting and totally unexplored characteristic of these nanofibrous scaffolds is their ability, when mechanically tested, to produce/transmit strain rate and nanofiber fracture-dependent mechanical vibrations, which can potentially influence surrounding tissues and cells. This study develops a method to investigate how scaffold geometry and material affect vibrational behavior under mechanical stimulation. Electrospun bundles of poly(L-lactic) acid/collagen type I (PLLA/Coll) were fabricated to mimic the fibrocartilage, the enthesis junction, and the tendon/ligament regions, while block copolymer poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT-PBT) bundles represented only the tendon/ligament. Scaffolds were morphologically and mechanically characterized, including strain rate-dependent vibrational response. Scanning electron microscopy confirmed distinct fiber architectures. Under monotonic tensile tests to failure, scaffolds exhibited strain rate-dependent mechanical behavior, with PLLA/Coll bundles showing dominant vibrational frequencies up to 4.2 {+/-} 0.9 Hz with a scaffolds geometry-dependent manner. PEOT-PBT scaffolds instead, displayed higher vibration attenuation, with dominant frequencies peaking at 0.539 {+/-} 0.063 Hz. They also showed lower tensile properties, reflecting a different mechanical and vibrational profile respect to PLLA/Coll bundles. Integrating vibrational characterization with mechanical testing offers a novel framework for designing scaffolds that more accurately reproduce the gradient mechanical environment of fibrous musculoskeletal tissues such as tendons/ligaments and their entheses. These findings highlight the potential of this combined approach to further increase the mechanical comprehension of electrospun scaffolds. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/699441v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@1e4f38dorg.highwire.dtl.DTLVardef@31e658org.highwire.dtl.DTLVardef@9c590org.highwire.dtl.DTLVardef@18996e9_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2024

RELATIONSHIP BETWEEN ACTUAL STRESS AND IN SITU MORPHOLOGICAL CHANGES IN THE MECHANICAL BEHAVIOR OF BIOMIMETIC POROUS HIERARCHICAL SCAFFOLDS

This study investigates the evolution with strain of the material volume fraction (i.e., porosity) and geometry in porous scaffolds to obtain a more accurate description of their stress-strain behavior. Single bundles and hierarchical structures (8 bundles enveloped by a membrane) were produced by electrospinning as tendon/ligament scaffolds. They underwent a micro-tomography in situ tensile test. Apparent and net stress were obtained using the initial sample cross-section and material volume fraction to normalize axial force. Micro-tomography revealed sample morphology change with strain to calculate the actual stress-strain. Moreover, nanofibers arrangement was revealed by scanning electron microscopy on both bundles and membranes. The description of the mechanical response significantly changed using evolving morphometry (actual stress-strain) instead of initial static one (apparent stress-strain), for both single bundle and hierarchical structure. The actual elastic modulus of the single bundles (583{+/-}97 MPa) was statistically higher than that of the hierarchical structures (163{+/-}107 MPa). This is related to the membrane, membrane-bundle and inter-bundle interactions. In the hierarchical structure, portions of the material resisting traction are constituted by nanofibers not aligned with the load. The different definitions for the stress-strain behavior allow different accuracy levels depending on the experimental complexity. The evolution of morphology with deformation can significantly affect the description of the mechanical response of porous scaffolds. This has a double impact in practical applications: at the body scale, it allows a better comparison between the scaffold behavior and the target tissue; at the cellular scale, it predicts the actual substrate stiffness that cells will face. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/630537v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@5d5337org.highwire.dtl.DTLVardef@1027047org.highwire.dtl.DTLVardef@11966a9org.highwire.dtl.DTLVardef@a2e4e3_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Full-field strain distribution in hierarchical electrospun nanofibrous Poly-L(lactic) acid and Collagen based scaffolds for tendon and ligament tissue regeneration: a multiscale study

Regeneration of injured tendons and ligaments (T/L) is a worldwide need. In this study electrospun hierarchical scaffolds made of a poly (L-lactic) acid and collagen blend were developed reproducing all the multiscale levels of aggregation of these tissues. Scanning electron microscopy, microCT and tensile mechanical tests were carried out, including a multiscale digital volume correlation analysis to measure the full-field strain distribution of electrospun structures. The principal tensile and compressive strains detected the pattern of strains caused by the nanofibers rearrangement, while the deviatoric strains revealed the related internal sliding of nanofibers and bundles. The results of this study confirmed the biomimicry of such electrospun hierarchical scaffolds, paving the way to further tissue engineering and clinical applications. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=92 SRC="FIGDIR/small/543145v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1a67baorg.highwire.dtl.DTLVardef@190149aorg.highwire.dtl.DTLVardef@38968borg.highwire.dtl.DTLVardef@123bb49_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗