Hydrogels are excellent cell-supportive materials for the in vitro modelling of human tissues. However, hydrogels made from natural polymer sources generally exhibit weak mechanical properties and low stability in vitro. The main challenge is in the generation of hard tissues, such as cartilage, by reproducing both the mechanical and biological in vivo microenvironment properties.
We aim to create an interpenetrating polymer network (IPN) hydrogel and bio-ink based on heat-sensitive chitosan (CH) and methacryloyl gelatin (GM) that enables cell encapsulation while demonstrating good mechanical properties to mimic cartilage.
Several IPN formulations based on CH and GM were evaluated on their physicochemical and bio-properties. CH-GM solutions were prepared at various ratios with fixed final concentration of CH (1.67% w/v). GM batches with low, medium and high degree of substitution (DS) were prepared (40, 60 and 90%) and evaluated within the IPN. The crosslinking kinetics was monitored by in situ rheology, applying blue light (405 nm, 1 500 mW) at 37°C leading to the chemical crosslinking of GM and the physical crosslinking of CH with ß-glycerolphosphate and sodium carbonate.
The addition of 2%GM with the higher DS to the CH network significantly enhances the mechanical properties of the hydrogel compared to CH alone (compressive modulus of ~40 kPa instead of 7 kPa). This improvement is largely attributed to the high number of methacrylate groups in GM, which considerably densifies the polymer network. This IPN is also more suitable for 3D printing without a support bath. Biocompatibility was assessed through L929 fibroblasts encapsulation within the selected ink, showing good cell viability and growth until the 7th day, with potential improvement by reducing the exposure time to 2 minutes.
We report here promising bio-inks from IPN hydrogel formulations based on natural polymers with enhanced mechanical properties and printability.
| Date | 17 Jan 2025 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Sophie Lerouge (Supervisor), Ali Ahmadi (Co-supervisor) & Inès Hamouda (Co-supervisor) |
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Gigodot, A. (Author),
Lerouge (Supervisor),
Ahmadi (Co-supervisor) & Hamouda (Co-supervisor),
17 Jan 2025Student thesis: Master's thesis › Master in Engineering: Engineering