pH-Responsive TiO₂ Nanotube Drug Delivery System Based on Iron Coordination

Abstract

Nanostructured materials play a fundamental role in orthopedic research owing to their outstanding properties and excellent biocompatibility. Titania nanotube (TNT) arrays engineered by electrochemical anodization process have been extensively explored and used as effective carriers for controlled drug delivery. In this study, we proposed a drug delivery system based on coordination bond. Iron (III), Fe3+, on the nanotube surface can effectively bind to alendronate sodium (NaAL), a drug for the treatment of osteoporosis, through coordination bonds, which can be formed or broken through the change of pH, and thus can be controlled by pH. The pH-responsive system was prepared by three-step procedure: (i) fabrication of TNTs by electrochemical anodization, (ii) modification of amino groups on the surface of nanotubes by hydrothermal method, and (iii) amino-functionalized nanotubes by Fe3+ solution soak. The Fe-modified TNTs not only allowed alendronate-loading content of up to 50.2% by weight, which is significantly higher than most drug delivery systems previously reported, but also delayed and prolonged drug release. Moreover, in vitro drug release experiments demonstrated that coordination bond-based TNT system may have great potential applications in clinical use.

Effect of size and crystalline phase of TiO2 nanotubes on cell behaviors: A high throughput study using gradient TiO2 nanotubes

“…Over the past decade, self-aligned TiO 2 nanotubes (TNTs) grown on titanium have been extensively developed in environmental protection, photocatalysis [ [6] , [7] , [8] ], sensors [ 9 , 10 ], dye-sensitized solar cells [ 11 , 12 ], and biomedical applications [ [13] , [14] , [15] ] owing to their superior high-specific surface area, specific ion intercalation properties, photocatalysis property, and cost-effective synthesis. In particular, the terrific biocompatibility, corrosion resistance and size controllable properties of TNTs make them promising for biomedical applications, such as orthopedic/dental implants [ 16 , 17 ], blood contact materials [ 18 ], anti-microbial application [ 19 , 20 ], and drug delivery [ 21 , 22 ].…”

Evaluation of sustained drug release performance and osteoinduction of magnetron-sputtered tantalum-coated titanium dioxide nanotubes

“…15 Previous studies have proposed to prepare TNTs on medical implants as a drug release platform for clinical application. 16 Moreover, TNTs with drug loading properties, biocompatibility, and pro-osteogenic promotion ability have attracted much interest, 17,18 whereas rapid drug release caused by the large and straight diameter of TNTs would compromise their application. 17,19 Therefore, effective techniques are urgently needed to control drug release from TNTs, promoting their biological properties and avoiding excessive local drug concentration.…”