Delipidation of Porcine Femur Bone and Porcine Pericardial Membrane Using Supercritical CO2 Extraction

REYNOSO, J.; GAÑÁN, N. A.; MURATURE, M.; VELEZ, A.R.; MILANESIO, J. M.

Los Cocos, Córdoba

Conferencia; VI Iberoamerican Conference on Supercritical Fluids (PROSCIBA 2023); 2023

IPQA/PLAPIQUI

It is well-established that to accelerate biological mechanisms for periodontal bone healing, guided tissue regeneration (GTR) and guided bone regeneration (GBR) techniques are employed. The common dental practice today involves the use of porcine pericardial membranes, composed of native collagen and combined with bone graft materials, in both GTR and GBR procedures. Porcine pericardial membranes are collagen-rich and exhibit rapid resorption. They are easily handled due to their high elasticity, facilitating their adherence to the defect.A critical step in the utilization of porcine pericardial membrane and femur bone for assimilation in dental applications is delipidation, as it ensures their absorption by the periodontal tissue. The residual lipids in bone act as a barrier to cell attachment, adversely altering its biocompatibility and osseointegration. Furthermore, it induces adverse reactions which can increase bone resorption and encapsulating fibrosis. Nevertheless, these disadvantages can be resolved by decellularization of bone materials using supercritical carbon dioxide (SCCO2) extraction. CO2 is the extracting solvent to remove the fats, cells, and non‐ collagenous proteins from the animal tissues. CO2 is a natural occurring solvent, safe, non‐ toxic, noncorrosive, non‐flammable, easily accessible, and cost effective. It presents mild critical coordinates, such as 7.38 MPa and 31°C, which can be relatively easily accessible.The supercritical CO2 extraction tests were carried out in a high-pressure batch system, which comprised a 100 cm3 stainless steel cell with internal stirring and temperature control. The extraction was conducted in two stages. The ethanol-wet bone or membrane sample was placed inside the extractor and CO2 was subsequently injected using a syringe pump until the desired pressure was reached. After stabilizing the pressure and temperature conditions (40°C and 200 bar), the system was left in static mode for 1 hour with continuous stirring. After static time, the cell was depressurized, the sample was removed, and its weight was measured to determine mass loss. The extractor cell was cleaned and dryed and the same sample was reloaded. The cycle was repeated for an additional hour. The results were compared against Soxhlet extraction to evaluate delipidation efficiency. The goal of this work was to assess the supercritical CO2 lipid extraction from porcine femoral head bone and from porcine pericardial membrane and characterize the fatty acid profile of the extracted lipids.The results show that supercritical CO2 extraction facilitated the delipidation of bone and membrane samples through a two-stage batch extraction scheme, achieving a 25% extraction yield. This suggests that a semi-continuous operation with a constant flow of supercritical CO2 for delipidation could be more efficient. The extraction technique did not exhibit diffusion issues, as the lipid extraction percentages remained consistent across various sizes of porcine bone and membrane.