Biology subjects

Zenobi, M.

Publications and source records attributed to Zenobi, M..

6 recordsLinked to original sources

bioRxiv2025

Tissue Engineered Elastic Cartilage-Mimetic Auricular Grafts for Ear Reconstruction

Patients born with microtia, the congenital malformation of the external ear, face substantial psychosocial strain. Current reconstruction relies on harvesting rib cartilage, an invasive procedure associated with donor site morbidity and unnaturally stiff ears due to the use of hyaline cartilage. Tissue engineered auricles could overcome these drawbacks by providing patient-specific elastic cartilage without the need for rib harvest. Yet, key challenges such as fibrocartilage formation, inhomogeneous extracellular matrix formation and mechanical inferiority during ex vivo maturation remain, often leading to graft deformation and degradation in vivo. To address this gap, we integrated approaches maintaining the chondrogenic potential with growth factors, promoting elastic cartilage formation through stress-relaxing materials, and achieving homogeneous maturation by culturing grafts on an elevated bioreactor platform that enables uniform nutrient diffusion, using primary human auricular chondrocytes. Together these approaches resulted in the maturation of bioprinted auricular grafts that closely resemble native human auricular cartilage, demonstrated by the uniform distribution of elastin, glycosaminoglycans, and collagen II, and lack of collagen I. RNA sequencing revealed gene expression patterns consistent with the transition from fibrocartilage towards elastic cartilage. On a functional level, grafts achieved a compressive modulus of 1.1{+/-}0.03 MPa, matching that of native human auricular cartilage (1.0{+/-}0.1 MPa) and maintained their structural integrity for 6 weeks in a subcutaneous rat model, where they transitioned towards mature elastic fibers. These grafts represent the closest approximation of native elastic cartilage achieved ex vivo to date, bringing the field closer to a clinically viable, long-term therapy for children affected by microtia. One-sentence summaryBioprinted auricular grafts develop native-like elastic cartilage and advance towards a durable therapy for children with microtia.

bioengineering↗

bioRxiv2025

Microbiome variations in osteoarthritis reflect aging and metabolic factors, not the disease

The gut microbiome is crucial for human health. Its disruption has been linked to several chronic diseases, including joint disorders. The gut-joint axis has been implicated in the pathogenesis of osteoarthritis (OA), but conflicting findings and study limitations have led to uncertainty regarding the role of microbiota. We conducted a multi-cohort gut microbiota analysis in 1,395 OA patients from four European cohorts (Lifelines, EstMB, FINRISK 2002, TwinsUK), using stringent exclusion criteria and matched controls. When assessing microbial diversity, taxa, functional gene profiles, and gut permeability biomarkers, no significant differences were found between OA and controls. Although this does not exclude a causal contribution of the microbiota in the gut-joint-axis, its dysbiosis does not seem to be linked with OA disease progression. Instead, age and BMI appeared as the main contributing factors to microbiome changes. Microbiome studies in complex diseases often face challenges such as small sample sizes, batch effects, and limited ability to match appropriate controls, particularly in single-cohort designs. By combining data from multiple large cohorts, we were able to mitigate these limitations and provide a more robust assessment of microbiome association with OA. Our findings emphasize the need for rigorous study design in microbiome research and challenge the OA-gut dysbiosis hypothesis.

microbiology↗

bioRxiv2025

Prolonged cell encapsulation and rapid filamented light biofabrication of muscle constructs in microgravity

The prospects of fabricating human tissue grafts or models using cell-laden bioresins in space has garnered significant interest in recent years. While there has been tremendous progress in extrusion or light-based bioprinting in microgravity conditions, printing of aligned tissues, such as those featuring anisotropic organization of cells and extracellular matrices (e.g., muscle, tendon, cardiac, etc.), remains a challenge. Furthermore, current photoresin formulations do not allow long-term cell encapsulation and are difficult to perform in microgravity. In this study, we demonstrate a new gravity-independent filamented light (G-FLight) biofabrication system with in-built refrigeration and heating units, which can create viable muscle constructs within seconds. We developed new photoresin formulations based on gelatin methacrylate (GelMA) for encapsulation of primary cells (murine myoblasts) and storage in printing cuvettes for at least a week at 4{degrees}C or -80{degrees}C. The tissues printed in microgravity based on the new formulations exhibited higher cell viability, number of proliferating cells and after maturation higher numbers of myotubes and fusion index compared to control formulations (i.e., GelMA dissolved in phosphate buffered saline). The microgravity-printed tissues also featured similar myotube density and fusion index to those printed using the same resins on-ground. The G-Flight printing concept, together with the new resins enabling refrigeration or cryopreservation with encapsulated cells, offers a promising solution for biofabrication in space.

bioengineering↗

bioRxiv2025

Filamented Light (FLight) Biofabrication of Mini-Tendon Models Show Tunable Matrix Confinement and Nuclear Morphology

One hallmark of healthy tendon tissue is the high confinement of tenocytes between tightly packed, highly aligned collagen fibers. During tendinopathy, this organization becomes dysregulated, leading to cells with round-shaped morphology and collagen fibers which exhibit crimping and misalignment. The elongated nuclei in healthy tendons are linked to matrix homeostasis through distinct mechanotransduction pathways, and it is believed that the loss of nuclear confinement could upregulate genes associated with abnormal matrix remodeling. Replicating the cell and nuclear morphology of healthy and diseased states of tendon, however, remains a significant challenge for engineered in vitro tendon models. Here we report on a high throughput biofabrication of mini-tendons that mimick the tendon core compartment based on the Filamented Light (FLight) approach. Each mini-tendon, with a length of 4 mm, was composed of parallel hydrogel microfilaments (2-5 {micro}m diameter) and microchannels (2-10 {micro}m diameter) that confined the cells. We generated four distinct matrices with varying stiffness (7-40 kPa) and microchannel dimensions. After 14 days of culture, 29% of tenocytes in the softest matrix with the largest microchannel diameter were aligned, exhibiting an average nuclear aspect ratio (nAR) of 2.1. In contrast, 84% of tenocytes in the stiffest matrix with the smallest microchannel diameter were highly aligned, with a mean nAR of 3.4. When tenocytes were cultured on the FLight hydrogels (2D) as opposed to within the hydrogels (3D), the mean nAR was less than 1.9, indicating that nuclear morphology is significantly more confined in 3D environments. By tuning the stiffness and microarchitecture of the FLight matrix, we demonstrated that mechanical confinement can be modulated to exert control over the extent of nuclear confinement. This high-throughput, tunable platform offers a promising approach for studying the mechanobiology of healthy and diseased tendons and for eventual testing of drug compounds against tendinopathy.

bioengineering↗

bioRxiv2025

Filamented Light (FLight) Bioprinting of Mini-Muscles with Self-Renewal Potential

The plasticity and regenerative capacity of skeletal muscle arise from quiescent stem cells activated upon overload, injury, or inflammation. Developing in vitro muscle models to study these properties could advance muscle disease modeling and pre-clinical evaluation. Here, we leverage Filamented Light (FLight) bioprinting as a high-throughput approach for producing mini-muscle tissues. Using Pax7-nGFP myoblasts, we bioprinted mini-muscles from pristine collagen-fibrinogen. The FLight hydrogel consisted of aligned microstructures which guided the formation of aligned myotubes. Mini-muscles demonstrated in vivo-like tissue organization, including highly aligned myotubes and a Pax7+ cell pool embedded in newly deposited laminin. Both spontaneous and electrically stimulated contractions were observed. Collagen-fibrinogen matrix was promising for maintenance of the Pax7+ cell pool. Damage from cardiotoxin-induced injury of the mini-muscles led to a massive proliferation of Pax7+ cells and restoration of the contractile properties. Notably, small molecules such as Repsox could enhance regeneration. FLight printed mini-muscles have potential for applications in muscle biology, exercise/atrophy, disease models, and drug screening.

bioengineering↗

bioRxiv2024

Anisotropic Articular Cartilage Biofabrication based on Decellularized Extracellular Matrix

Tissue-engineered grafts that mimic articular cartilage show promise for treating cartilage injuries. However, engineering cartilage cell-based therapies to match zonal architecture and biochemical composition remains challenging. Decellularized articular cartilage extracellular matrix (dECM) has gained attention for its chondro-inductive properties, yet dECM-based bioinks have limitations in mechanical stability and printability. This study proposes a rapid light-based bioprinting method using a tyrosine-based crosslinking mechanism, which does not require chemical modifications of dECM and thereby preserves its structure and bioactivity. Combining this resin with Filamented Light (FLight) biofabrication enables the creation of cellular, porous, and anisotropic dECM scaffolds composed of aligned microfilaments. Specifically, we investigate the effects of various biopolymer compositions (i.e., hyaluronic acid, collagen I, and dECM) and inner architecture (i.e., bulk light vs FLight) on immune response and cell morphology, and we investigate their influence on nascent ECM production and long-term tissue maturation. Our findings highlight the importance of FLight scaffolds in directing collagen deposition resembling articular cartilage structure and promoting construct maturation, and they emphasize the superiority of biological-rich dECM over single-component materials for engineering articular cartilage, thereby offering new avenues for the development of effective cartilage tissue engineering strategies.

bioengineering↗