Amin Shavandi

Diblock copolymers based on oligo(ethylene glycol) methacrylates form thermogels that can be further chemically crosslinked, demonstrating their potential for extrusion-based 3D printing and volumetric additive manufacturing.

Articular cartilage has limited self-repair capacity, and current treatments fail to fully restore its structure and function. 3D hydrogels that support chondrocyte viability and extracellular matrix (ECM) deposition offer a promising strategy for cartilage regeneration. Here, we developed a photo-crosslinkable silk fibroin–hyaluronic acid hydrogel for 3D encapsulation of primary human chondrocytes. Hydrogels were formulated with varying silk fibroin methacrylate (SilMA, 10-20% w/v) and hyaluronic acid methacrylate (HAMA, 1-2% w/v) concentrations and characterized for rheological, mechanical, and morphological properties. All SilMA-HAMA hydrogel formulations exhibited shear-thinning behavior and rapidly gelled (<20 s) under UV irradiation while maintaining high porosity, thereby ensuring injectability and efficient nutrient diffusion. Notably, the Young’s modulus of the cell-laden scaffolds increased from ~18 kPa to ~1200 kPa over culture, indicating mechanical maturation driven by chondrocyte-mediated matrix deposition. This maturation was further confirmed by histological analysis and qPCR, which demonstrated enhanced ECM production and chondrogenic gene expression. Taken together, these results highlight SilMA-HAMA hydrogels as a promising biomimetic platform that couples mechanical reinforcement with biological functionality for cartilage tissue engineering.

Articular cartilage has limited self-repair capacity, and current treatments fail to fully restore its structure and function. 3D hydrogels that support chondrocyte viability and extracellular matrix (ECM) deposition offer a promising strategy for cartilage regeneration. Here, we developed a photo-crosslinkable silk fibroin–hyaluronic acid hydrogel for 3D encapsulation of primary human chondrocytes. Hydrogels were formulated with varying silk fibroin methacrylate (SilMA, 10-20% w/v) and hyaluronic acid methacrylate (HAMA, 1-2% w/v) concentrations and characterized for rheological, mechanical, and morphological properties. All SilMA-HAMA hydrogel formulations exhibited shear-thinning behavior and rapidly gelled (<20 s) under UV irradiation while maintaining high porosity, thereby ensuring injectability and efficient nutrient diffusion. Notably, the Young’s modulus of the cell-laden scaffolds increased from ∼18 kPa to ∼1200 kPa over culture, indicating mechanical maturation driven by chondrocyte-mediated matrix deposition. This maturation was further confirmed by histological analysis and qPCR, which demonstrated enhanced ECM production and chondrogenic gene expression. Taken together, these results highlight SilMA-HAMA hydrogels as a promising biomimetic platform that couples mechanical reinforcement with biological functionality for cartilage tissue engineering.

This study investigates Ga-loaded porous phosphate glass fibres coated with clove oil as multifunctional materials capable of antioxidant, antibacterial, and wound-healing properties.

This study investigates how geometrical variations in volumetrically printed (Vol3DP) structures influence the attachment, survival, and organization of human umbilical vein endothelial cells (HUVECs) and osteosarcoma cells (143b). A gelatin methacryloyl–poly(ethylene glycol) diacrylate (GelMA–PEGDA) resin was optimized for volumetric bioprinting. Compared to GelMA, Gel–PEG enhanced printing fidelity, mechanical properties, and dimensional stability. Disc‐like constructs and channels with straight or angled geometries (60°, 90°, 110°) were fabricated and cultured with both cell types for up to 14 days. Label‐free holographic microscopy allowed real‐time visualization of cellular protrusions, critical for adhesion and mechanosensing, without staining, enabling long‐term live‐cell analysis in 3D constructs. HUVECs adhered, expressed CD31, and exhibited geometry‐dependent spreading, reflecting their native mechanosensitivity and alignment during vascular morphogenesis. In contrast, 143b cells spread uniformly, formed dense, geometry‐independent aggregates, and showed enhanced growth in Gel–PEG compared to GelMA, consistent with their aggressive, metastatic behavior. These findings demonstrate that Gel–PEG provides a stable, biomimetic matrix suitable for high‐resolution Vol3DP and that holographic microscopy enables dynamic assessment of cell–material interactions. Together, they underscore the potential of this approach for engineering vascularized tissue models and for studying mechanobiological responses in both endothelial and cancer cell systems.

Polycaprolactone (PCL) is widely utilized in biomedical applications such as tissue engineering and drug delivery; however, its limited bioactivity remains a key challenge. In this study, bioactive curcumin–polycaprolactone block copolymers (MCP) were synthesized via ring-opening polymerization of ε-caprolactone and maleic anhydride modified curcumin. The resulting MCP was characterized using FTIR, ¹H NMR, UV–Vis spectroscopy, and differential scanning calorimetry (DSC). It demonstrated enhanced antioxidant activity, UV-blocking capacity, and electro spinnability compared to PCL. Electrospun MCP films exhibited improved biocompatibility and promoted fibroblast migration. Furthermore, composite films incorporating MCP into a PVA matrix with and without copper or iron were evaluated for in vivo toxicity and antimicrobial activity. These formulations showed no systemic or contact toxicity in the Galleria mellonella model, confirming their biocompatibility. Films containing copper or iron exhibited selective anti-Pseudomonas aeruginosa activity and low but reproducible antioxidant capacity. This study highlights the multifunctionality and biomedical potential of MCP and its composites as tunable platforms for regenerative and antimicrobial applications.

Creating perfusable vascular networks that replicate physiological flow remains a key challenge in tissue engineering. Here, we present a volumetric 3D printing (Vol3DP) method for fabricating tunable, biologically relevant vascular structures that enable controlled perfusion. A recyclable resin of methacrylated gelatin (GelMA) and polyethylene glycol diacrylate (PEGDA) was optimized for Vol3DP to produce high-fidelity hydrogels with embedded channels. To evaluate the relationships between flow, structure, and function, we designed modular perfusion platforms that offer precise control over physiological shear stress (3–50 dyne/cm²), flow rates (1–15 mL/min), and flow modes, including pulsatile and continuous. These platforms support endothelial cell attachment and spreading under static seeding conditions, sustained perfusion, and permeability assessment and further allow for direct comparisons of flow dynamics and perfusion efficiency in channel-in-hydrogel systems. The finally engineered adaptable platform allowed for independent pressure modulation within the vessel and the outside environment. We conducted simulations of flow and hydrogel permeability that closely resemble experimental results. These results underscore the dominance of diffusive transport through the hydrogel matrix and highlight the ability of our system to simulate physiologically relevant mass transfer phenomena. Finally, we conducted a pilot study using Galleria mellonella larvae to compare active and passive dye transport in vivo , complementing in vitro data and highlighting the importance of perfusion-capable scaffolds for accurately simulating vascular drug delivery environments. Abstract Figure:

This study investigates the influence of geometrical variations in volumetrically printed (Vol3DP) structures on the attachment, survival, and organization of cancer cells (143b) and human umbilical vein endothelial cells (HUVECs). We adapted a gelatin methacryloyl (GelMA)–poly(ethylene glycol) diacrylate (Gel-PEG) resin for volumetric bioprinting. Compared to GelMA, Gel-PEG improved printing fidelity and resolution, superior mechanical properties, and reduced swelling. We fabricated disc-like constructs and channel geometries, including straight channels and angular designs of 60°, 90°, and 110° and cultured human umbilical vein endothelial cells (HUVECs) and 143b human osteosarcoma cells, a highly metastatic cell line, for up to 14 days. Using label-free holographic microscopy, we visualized cellular protrusions, important for adhesion and mechanosensing, in real-time and without staining, an advantage for long-term, live-cell analysis in 3D constructs. HUVECs adhered well, expressed CD31, and showed preferential spreading in channels with specific geometrical angles, indicating geometry-sensitive behavior. This is physiologically relevant, as it reflects the native mechanosensitive and alignment behavior of endothelial cells during vascular formation. In contrast, osteosarcoma cells spread uniformly throughout the constructs, formed dense, geometry-independent agglomerates, and exhibited enhanced growth and spreading within the Gel-PEG matrix compared to GelMA. This behavior is consistent with the aggressive and geometry-insensitive nature of metastatic tumor cells. These findings highlight Gel-PEG’s utility for generating stable, biomimetic 3D environments and demonstrate the application of holographic microscopy for assessing cell– material interactions within volumetrically bioprinted constructs, underscoring the potential of this approach for developing vascularized models and studying mechanobiological responses in engineered tissues. Abstract Figure: