Fumarate/Ceramic Composite Based Scaffolds for Tissue Engineering: Evaluation of Hydrophylicity, Degradability, Toxicity and Biocompatibility

Abstract

The present study was designed to investigate the possible cytotoxicity and biocompatibility of scaffolds based on previously characterized polymeric materials including poly--caprolactone (PCL) or polydiisopropyl fumarate (blended or on their own), with or without hydroxyapatite (HAP). Water contact angle was also evaluated to determine the hydrophylicity of each scaffold. Degradation of different scaffolds was evaluated after a 10-week incubation in Dulbecco's modified eagle medium (DMEM) supplemented with 5% (v/v) fetal bovine serum (FBS). Bone Marrow Stromal Cells (MSC) were grown on different scaffolds in an osteogenic medium, after which alkaline phosphatase activity (ALP) was evaluated. ALP activity increased when MSC were grown on PCL + HAP or Blend + HAP, as compared to PCL or Blend without HAP. The effect of different scaffolds on the proliferation of the macrophage cell line RAW 264.7, production of nitric oxide (NO) and secretion of pro-inflammatory cytokines was examined. After 72 h, macrophages proliferated equally well on all scaffolds, maintaining a rounded morphology. None of the investigated scaffolds induced production of NO or cytokine release into the culture media, suggesting an absence of cytotoxicity. Therefore, these polymer-and HAP-based scaffolds could potentially be used as bone substitute materials.

Ultrasonic compatibilization of polyelectrolyte complex based on polysaccharides for biomedical applications

“…Cells seem to maintain their round morphology without cytoplasmic extensions, 72 h after culture. As we have previously reported, when these cells are exposed to lipopolysaccharide (LPS) as a positive control of cytotoxicity, they show an expanded and vacuolated cytoplasm with several extensions, suggesting activation of the macrophages [28]. In addition, we have evaluated the potential cytotoxicity by the release of NO to the culture media.…”

“…This cell line has previously been used in our laboratory to assess cytotoxicity since it represents an adequate and sensitive in vitro model for inflammation [28,29]. For the experiments, PEC scaffolds were cut to size, inserted in a 24-well plate, sterilized by immersion in 70% ethanol and irradiated with UV light.…”

Biodegradable polyester networks including hydrophilic groups favor BMSCs differentiation and can be eroded by macrophage action

“…PCL and PLLA homopolymer films were prepared as we have previously described [21]. Briefly, PCL and PLLA were dissolved in chloroform and casted into a glass Petri dish.…”

“…Bone marrow stromal cells (BMSCs) and Murine macrophage RAW 264.7 cells were grown in DMEM (Invitrogen, Buenos Aires, Argentina) containing 10% FBS (Natacor, Argentina), 100 U/ml penicillin and 100 mg/ml streptomycin at 37 C in a 5% CO 2 atmosphere [21]. Bone marrow stromal cells were obtained from rats as described previously and characterized by their ability to differentiate to various phenotypes, such as osteoblasts, adipocytes and chondrocytes.…”

“…To determine ALP, cell monolayers were washed with PBS and the total cell extract was obtained with 200 mL 0.1% Triton-X100 (Sigma Aldrich, USA). A 100 mL aliquot of the extract was used to evaluate ALP by hydrolysis of p-nitrophenylphosphate (p-NPP) (Sigma Aldrich, USA) into p-nitrophenol (p-NP) at 37 C for 1 h. The absorbance of p-NP was recorded at 405 nm [21]. Aliquots of each cell extract were used for protein determination by Bradford's technique [24].…”