Evaluation of physicochemical and mechanical properties with the in vitro degradation of PCL/nHA/MWCNT composite scaffolds

Abstract

The fabrication of biodegradable magnetic poly(caprolactone)(PCL)/nanohydroxyapatite (nHA)/multiwalled carbon nanotube (MWCNT) composite scaffolds by thermally induced phase separation (TIPS) for bone regeneration is reported in this study. The magnetism tests completed on the porous matrices pointed to their ferromagnetic behavior. Both in-vitro degradation and mechanical properties are studied over eight weeks in a phosphate buffered solution (PBS) at 37°C. The addition of MWCNTs at quantities of up to 5% modified the structural morphology of the composite, producing regular structures with repetitive patterns. As from that quantity, the electrostatic charge of the nanotubes within an aqueous solution was insufficient for acceptable distribution of the nanoparticles, by means of ultrasonic dispersion. It resulted in an acceleration of the degradation behavior that was clear from the mechanical properties that weakened by up to 20%. The thermal properties were also influenced in that they formed shorter chains, which could be ordered with greater ease, as a consequence of the ester hydrolysis process.

Recent Progress on Biodegradable Tissue Engineering Scaffolds Prepared by Thermally-Induced Phase Separation (TIPS)

“…Polyester-based scaffolds reinforced with multiwalled carbon nanotubes (MWCNTs) have recently been produced by TIPS [ 19 , 243 , 244 ]. Possessing a wide variety of properties such as electrical, thermal, mechanical and structural, MWCNTs have been reported as proper candidates for biomedical applications [ 245 ].…”

“…The effect of higher levels of MWCNTs (i.e., 1–10 wt%) and the incorporation of HA (i.e., 10 wt%) on PCL-based scaffold properties was subsequently evaluated. Samples were obtained by ultrasonic dispersion of MWCNTs and nHA particles in PCL-dioxane solutions followed by TIPS to get porous composite matrices [ 243 ]. Despite the excellent properties of CNTs, having other features like high surface area, small diameter and high aspect ratio (>1000) predispose them to form agglomerates when being incorporated as reinforcements into biopolymers, especially in high loading levels [ 248 ].…”

“…Despite the excellent properties of CNTs, having other features like high surface area, small diameter and high aspect ratio (>1000) predispose them to form agglomerates when being incorporated as reinforcements into biopolymers, especially in high loading levels [ 248 ]. They reported that both mechanical properties and in vitro degradation were clearly modified by adding MWCNTs: up to 5% of MWCNTs the structural arrangement of the scaffolds was positively changed, but higher levels led to agglomeration, an irregular structure and a negative effect on mechanical properties [ 243 ]. The decrease of nHA content to 1 wt%, allowed a clear evaluation of the influence of various levels of MWCNTs (1–10 wt%).…”

Solution-Based Processing for Scaffold Fabrication in Tissue Engineering Applications: A Brief Review

“…Recently, diverse solution-based techniques have been combined to obtain a 3D porous structure with interconnected pores for TE applications. The TIPS technique is a commonly used method to fabricate TE scaffolds due to its simplicity and effectiveness in adjusting the structure and properties to the application of materials [70,74]. Carfì et al [101] combined TIPS and DIPS to produce a multifunctional scaffold with easy-tunable pore size, porosity, and thickness.…”

“…It was observed that chondrogenic differentiation and control of vascularization were strongly dependent on the manufacturing process, which, in its turn, is effective in modulating scaffold pore dimensions. Diaz et al [ 74 ] also studied the influence of the use of particles and fabrication parameters of the TIPS process on the thermal and mechanical properties of poly(caprolactone; PCL)/nanohydroxyapatite (nHA)/multiwalled carbon nanotube (MWCNT) composite scaffolds. They found that it is possible to fabricate composite scaffold structures using nano carbons and hydroxyapatite via TIPS by a process optimization based on the application of ultrasonic dispersion.…”