Introduction: Nano-topological bio-interfaces of metallic implants have been a critical feature in modulating cellular responses and achieving bio-functional success. The electrophoretic deposition (EPD) is a simple process where a wide range of coating materials can be usedwith tunable composition and thickness in a time and cost effective manner. In present study, we produced carbon nanotube (CNT) /chitosan (Chi) hybrid surfaces on titanium plate using electrophoretic deposition (EPD) technique.
Materials and Methods: Acid treated CNTs were dispersed in chitosan(0.125-0.5mg/mL). The CNT-chitosansolutions were electrodeposited on titanium substrate under DC field. The coatings were characterized by TGA, ATR-FTIR and XRD. Stability and bioactivity of the coatings were performed by incubation in PBS and simulated body fluid, respectively. The potential of the coatings to load and deliver biomolecules was studied usinga model protein BSA.Murine pre-osteoblastic cells were cultured on the surface to investigate the effects of nano-topographic surfaces on the cell adhesion events.
Results and Discussion: Depending on the electrophoretic deposition parameters, a wide range of CNT-chitosan compositions with varying thickness were successfully produced. The coatings presented good stability in a saline solution and a fast deposition of an apatitemineral phase when immersed in a simulated body fluid. Due to the increased surface area of the nanostructured surfaces as well as the higher electrostatic charges of the composition, the adsorption of proteins was substantially enhanced on the CNT-chitosan surfaces. The CNT-chitosan surfaces allowed for a sustained release of BSA molecules over two weeks through a diffusion controlled mechanism. The nanostructuredsurfaces up-regulated a series of cell adhesion events, includingcell anchorage, spreading, and the expression of focal adhesion proteins.
Conclusion: The CNT-basednanostructured hybrid surfaces stimulated the initial cellular activity through the nano-topological features, andenhancedthe loadingand delivery capacity of biomolecules. The nanostructures can be considered as a possible interfacethat mediates the interactions of metallic implants with biomolecules and cells.
This work was supported by the grants from the National Research Foundation, Republic of Korea; Priority Research Centers Program (No. 2009-0093829) and Global Research Lab Program (2015032163).
References:
[1] Nanostructured biointerfacing of metals with carbon nanotube/chitosan hybrids by electrodeposition for cell stimulation and therapeutics delivery. Patel KD1, Kim TH, Lee EJ, Han CM, Lee JY, Singh RK, Kim HW.ACS Appl Mater Interfaces. 2014 Nov 26; 6(22):20214-24.