Biology subjects

Shavandi, A.

Publications and source records attributed to Shavandi, A..

4 recordsLinked to original sources

bioRxiv2026

Photocrosslinkable silk fibroin-hyaluronic acid hybrid hydrogels enable chondrocyte-driven matrix deposition and mechanical maturation 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 Youngs 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.

bioengineering↗

bioRxiv2025

Controlling Flow Dynamics and Permeability in Perfusable Vascular Constructs Using Volumetric 3D Printing

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/cm{superscript 2}), 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. O_FIG O_LINKSMALLFIG WIDTH=172 HEIGHT=200 SRC="FIGDIR/small/669590v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@1add089org.highwire.dtl.DTLVardef@56057forg.highwire.dtl.DTLVardef@182e989org.highwire.dtl.DTLVardef@1b235a3_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

Geometrical Designs in Volumetric Bioprinting to Study Cellular Behaviors in Engineered Constructs

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{degrees}, 90{degrees}, and 110{degrees} 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-PEGs 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. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=193 SRC="FIGDIR/small/664683v1_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@9e3820org.highwire.dtl.DTLVardef@176eb5aorg.highwire.dtl.DTLVardef@558764org.highwire.dtl.DTLVardef@12bc5cb_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2021

Enhanced keratin extraction from wool waste using a deep eutectic solvent

In this study, the solubilisation of waste coarse wool as a precursory step for the large scale valorisation of keratin was investigated using a green deep eutectic solvent (DES) based on L-cysteine and lactic acid. The investigation was undertaken via the response surface methodology and based on the Box-Behnken design for four process variables of temperature (70-110 {degrees}C), dissolution time (2-10 h), the mass of L-cysteine (0.5-2.5 g) in 20 mL of lactic acid, and wool load in the DES (0.2-0.6 g). The effect of variations in temperature was established to be the most significant process variable influencing keratin yield from waste coarse wool in the current work. An optimum keratin yield (93.77 wt.%) was obtained at the temperature of 105 {degrees}C, 8 h dissolution time, with 1.6 g L-cysteine in 20 mL of lactic acid using 0.5 g of wool. This study suggests L-cysteine and lactic acid as a green solvent with the potential to scale up keratin recovery from waste wool without significant destruction in the structure of the recovered keratin. HighlightsO_LIKeratin recovery from wool using deep eutectic solvent was assessed C_LIO_LIThe basis for the use of the new deep eutectic solvent was discussed C_LIO_LIThe effects of the process variables on keratin yield were explored C_LIO_LIKeratin recovered was optimised and characterised. C_LI

bioengineering↗