Engineered titanium implants for localized drug delivery: recent advances and perspectives of Titania nanotubes arrays

ABSTRACT

Introduction: Therapeutics delivery to bones to treat skeletal diseases or prevent postsurgical infections is challenging due to complex and solid bone structure that limits blood supply and diffusion of therapeutics administered by systemic routes to reach effective concentration. Titanium (Ti) and their alloys are employed as mainstream implant materials in orthopedics and dentistry; having superior mechanical/biocompatibility properties which could provide an alternative solution to address this problem.

Areas covered: This review presents an overview of recent development of Ti drug-releasing implants, with emphasis on nanoengineered Titania nanotubes (TNTs) structures, for solving key problems to improve implants osseointegration, overcome inflammation and infection together with providing localized drug delivery (LDD) for bone diseases including cancer. Critical analysis of the advantages/disadvantages of developed concepts is discussed, their drug loading/releasing performances and specific applications.

Expert opinion: LDD to bones can address many disorders and postsurgical conditions such as inflammation, implants rejection and infection. To this end, TNTs-Ti implants represent a potential promise for the development of new generation of multifunctional implants with drug release functions. Even this concept is extensively explored recently, there is a strong need for more preclinical studies using animal models to confirm the long-term safety and stability of TNTs-Ti implants for real-life medical applications.

KEYWORDS:

• Localized drug delivery
• titanium implants
• osseointegration
• Titania nanotubes

Article highlights

• Localized drug delivery from titanium implants represents a promising approach to treat many bone conditions which are hard be treated using systemic drug therapies.

• Titania Nanotubes (TNTs) modified implants are considered as a unique platform for combining enhanced bone integration and localized drug delivery.

• TNTs show a set of unique properties such as mechanical and thermal stability, improved osseointegration, biocompatibility, and structural flexibility.

• The fabrication of TNTs using electrochemical anodization process permits precise control over the tubular structure and dimensions which provide versatile applicability of TNTs in biomedical field.

• A wide range of therapeutics (anti-inflammatory, antibacterial, anticancer, and growth factors) was loaded inside TNTs and tested for controlled release as well as ‘on demand’ release kinetics.

• - 3D printing technology will open new doors for ‘on demand’ manufacturing of different forms of implants specially designed according to patient’s needs.

• More in-vivo studies are required to establish the long-term toxicity and to translate this technology into clinical applications.

This box summarizes key points contained in the article.

Acknowledgments

The authors acknowledge the financial support provided to S. Maher by the Australian Government Training Program Scholarship, and Forrest George and Sandra Lynne Young Supplementary Scholarship.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.