Supercritical CO2 processing of a chitosan-based scaffold: Can implantation of osteoblastic cells be enhanced?

The effects of fabrication techniques were investigated for preparation of a chitosan based scaffold. A two-step process was used: fabrication of hydrogel which was subsequently processed either with supercritical CO2 (SC-CO2) or lyophilization. Various pressures from subcritical to supercritical (70, 160, 250 bar), temperatures (35, 45, 55 °C) and durations (2–3 h) were applied in order to elicit the optimum process parameters yielding the highest porosity which were determined as 250 bar, 45 °C, 2 h of processing at 5 g/min CO2 flow rate yielding a porosity of 87.03% which was similar to lyophilization (88.68%) achieved at 55 °C for 48 h. When osteosarcoma cells possessing cellular features of osteoblasts were seeded, SC-CO2 dried scaffold proved to be a more ideal support for cell attachment owing to the presence of both nano and micropores, thereby providing a more efficient and rapid alternative for tissue engineering applications.

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► Chitosan based scaffolds were subjected to supercritical CO2 drying and lyophilization.
► A linear driving force model was used based on mass transfer balances.
► The highest porosity was 87.03% achieved at 250 bar, 45 °C, 2 h at a flow rate of 5 g/min.
► The porosity of lyophilized sample was 88.68% operated at 55 °C for 48 h.
► Supercritical CO2 dried scaffold proved to be a more ideal support for cell attachment.