3D porous collagen/functionalized multiwalled carbon nanotube/chitosan/hydroxyapatite composite scaffolds for bone tissue engineering.

In this study, we describe new collagen/functionalized multiwalled carbon nanotube/chitosan/hydroxyapatite (Col/f-MWCNT/CS/HA) composite scaffolds which were fabricated by freezing (-40 °C at 0.9 °C/min) and lyophilization (48 h, 0 °C and 200 mtorr). The compressive stresses (from 523 to 1112 kPa), swelling (from 513.9 ± 27 to 481.05 ± 25%), porosity (from 98 ± 0.15 to 95.7 ± 0.1%), contact angle (from 87.8 to 76.7°) properties examined before and after biomineralization for comparison 3D porous Col, CS, Col/f-MWCNT and Col/f-MWCNT/CS scaffolds. Biomineralization was performed by biomimetic method in concentrated SBF (10 × SBF, at 37 °C and 6.5 pH). XRD, SEM, EDS, FTIR, TGA, Optical microscopy and BET results showed that compared to Col, CS and Col/f-MWCNT scaffolds, Col/f-MWCNT/CS scaffolds had higher in vitro bioactivity, large surface area (11.746 m2/g) and a good pore volume (0.026 cc/g), interconnected porous microstructure (with 20-350 μm pore size) and incorporates the advantageous properties of both Col, f-MWCNT, CS and HA. Finally, the methyl thiazolyl tetrazolium (MTT) assay was performed to evaluate scaffolds cytotoxicity which showed that Col/f-MWCNT/CS scaffolds have the best biocompatibility.