Fabrication and characterization of drug-loaded nano-hydroxyapatite/polyamide 66 scaffolds modified with carbon nanotubes and silk fibroin

Abstract

Nano-hydroxyapatite/polyamide 66 (nHA/PA66) porous scaffolds were fabricated by a phase inversion method. Carbon nanotubes (CNTs) and silk fibroin (SF) were used to modify the surface of the nHA/PA66 scaffolds by freeze-drying and cross-linking. Dexamethasone was absorbed to the CNTs to promote the osteogenic differentiation of bone mesenchymal stem cells (BMSCs). The cell viability of BMSCs was investigated by changing the concentration of the CNT dispersion, and the most biocompatible scaffold was selected. In addition, the morphology and mechanical property of the scaffolds were investigated. The results showed that the nHA/PA66 scaffolds modified with CNTs and SF met the requirements of bone tissue engineering scaffolds. The dexamethasone-loaded CNT/SF-nHA/PA66 composite scaffold promoted the osteogenic differentiation of BMSCs, and the drug-loaded scaffolds are expected to function as effective bone tissue engineering scaffolds.

Keywords:

• BMSCs
• tissue engineering
• porous scaffold
• carbon nanotubes
• silk fibroin
• surface modification
• dexamethasone

Supplementary materials

Figure S1 The electrical conductivity of nHA/PA66, 0.2 mg/mL CNT/SF-nHA/PA66, 0.5 mg/mL CNT/SF-nHA/PA66, and 1 mg/mL CNT/SF-nHA/PA66 scaffolds.

Abbreviations: CNT, carbon nanotube; nHA, nano-hydroxyapatite; PA66, polyamide 66; SF, silk fibroin.

Figure S2 HPLC fingerprint spectrum of DEX.

Notes: Chromatographic column, Diamonsil C18 (5 µm, 250×4.6 mm); mobile phase, acetonitrile monohydrate (4:6); flow rate, 1 mL/min; sample quantity, 20 µL; detection wavelength, 240 nm; column temperature, 25°C.

Abbreviations: DEX, dexamethasone; HPLC, high-performance liquid chromatography.

Figure S3 HPLC standard curve of DEX.

Abbreviations: DEX, dexamethasone; HPLC, high-performance liquid chromatography.

Table S1 The result of intraday and interday precision (n=5)

Table S2 The stability of dexamethasone (n=3)

Table S3 The recovery rate (n=5)

Acknowledgments

We are grateful to the Core Facility of Zhejiang University of Medicine for technical assistance in confocal laser scanning microscopy. Also, we would like to acknowledge the Analysis Center of Agrobiology and Environmental Science for assistance in transmission electron microscopy service.

Disclosure

The authors report no conflicts of interest in this work.