Electrically controlled drug release from nanostructured polypyrrole coated on titanium

Area of Science:

• Biomaterials Science
• Nanotechnology
• Orthopedic Engineering

Background:

• Multi-walled carbon nanotubes on titanium (MWNT-Ti) show promise as sensing electrodes for biomedical applications, detecting proteins during bone formation.
• Polypyrrole (PPy) is known to release drugs upon electrical stimulation, making it a candidate for controlled drug delivery systems.

Purpose of the Study:

• To electrodeposit polypyrrole (PPy) doped with antibiotics (penicillin/streptomycin, P/S) or dexamethasone (Dex) onto titanium (Ti).
• To investigate the on-demand drug release capabilities of these PPy-Ti materials via electrical stimulation.
• To evaluate the effect of these drug-releasing PPy-Ti materials on osteoblast and fibroblast cell behavior for orthopedic applications.

Main Methods:

• Electrodeposition of PPy films doped with P/S or Dex onto Ti substrates.
• Atomic force microscopy (AFM) for surface roughness analysis.
• X-ray photoelectron spectroscopy (XPS) for drug encapsulation confirmation.
• Cyclic voltammetry to assess drug release kinetics under electrical stimulation.
• In vitro cell culture studies to evaluate osteoblast and fibroblast adhesion on PPy-Ti films.

Main Results:

• PPy films exhibited nanometer-scale roughness.
• XPS confirmed successful encapsulation of P/S and Dex within the PPy matrix.
• Cyclic voltammetry demonstrated an 80% drug release on demand within five cycles at 0.1 V/s.
• PPy[Dex] enhanced osteoblast adhesion, while PPy-Ti (with or without drugs) inhibited fibroblast adhesion compared to plain Ti.

Conclusions:

• Electrodeposited PPy[P/S] and PPy[Dex] on Ti can release drugs on demand, offering potential for combating infection, reducing inflammation, and promoting bone growth.
• These materials can modulate cellular behavior, inhibiting fibroblast adhesion and enhancing osteoblast adhesion, suggesting utility in orthopedic applications.
• The developed PPy-Ti materials show promise as implantable sensors with integrated drug delivery capabilities for orthopedic interventions.