Electrophoretic Deposition of Chitosan Coatings on the Porous Titanium Substrate

Abstract

Medicine is looking for solutions to help implant patients recover more smoothly. The porous implants promote osteointegration, thereby providing better stabilization. Introducing porosity into metallic implants enhances their biocompatibility and facilitates osteointegration. The introduction of porosity is also associated with a reduction in Young's modulus, which reduces the risk of tissue outgrowth around the implant. However, the risk of chronic inflammation remains a concern, necessitating the development of coatings to mitigate adverse reactions. An interesting biomaterial for such modifications is chitosan, which has antimicrobial, antifungal, and osteointegration properties. In the present work, a porous titanium biomaterial was obtained by powder metallurgy, and electrophoretic deposition of chitosan coatings was used to modify its surface. This study investigated the influence of ethanol content in the deposition solution on the quality of chitosan coatings. The EPD process facilitates the control of coating thickness and morphology, with higher voltages resulting in thicker coatings and increased pore formation. Ethanol concentration in the solution affects coating quality, with higher concentrations leading to cracking and peeling. Optimal coating conditions (30 min/10 V) yield high-quality coatings, demonstrating excellent cell viability and negligible cytotoxicity. The GIXD and ATR-FTIR analysis confirmed the presence of deposited chitosan coatings on Ti substrates. The microstructure of the chitosan coatings was examined by scanning electron microscopy. Biological tests showed no cytotoxicity of the obtained materials, which allows for further research and the possibility of their use in medicine. In conclusion, EPD offers a viable method for producing chitosan-based coatings with controlled properties for biomedical applications, ensuring enhanced patient outcomes and implant performance.

Keywords: chitosan; electrophoretic deposition; porous titanium.

Figure 1

Microscopic image of the studied Ti sample surface.

Figure 2

SEM images of the chitosan coatings deposited from the starting solution: (a,b) (5 min/2.5 V); (c–e) (5 min/10 V); (f–h) (5 min/20 V); (i–k) (30 min/10 V).

Figure 3

SEM images of the chitosan coatings deposited from solution 1 (25% ethanol): (a,b) (5 min/2.5 V); (c–e) (5 min/10 V); (f–h) (5 min/20 V); (i–k) (30 min/10 V).

Figure 4

SEM images of the chitosan coatings deposited from solution 2 (50% ethanol): (a,b) (5 min/2.5 V); (c–e) (5 min/10 V); (f–h) (5 min/20 V); (i–k) (30 min/10 V).

Figure 5

SEM images of the chitosan coatings deposited from solution 3 (75% ethanol): (a,b) (5 min/2.5 V); (c–e) (5 min/10 V); (f–h) (5 min/20 V); (i–k) (30 min/10 V).

Figure 6

SEM images of the chitosan coatings deposited from the starting solution at 5 min/20 V, and the EDS analysis of the marked areas.

Figure 7

Result of EDS analysis of chitosan coatings on Ti substrate obtained from: (a) starting solution at 10 min/10 V, (b) solution 1 at 15 min/10 V, (c) solution 2 at 20 min/10 V, and (d) solution 3 at 10 min/10 V.

Figure 8

GIXD patterns for the angle of incidence α = 0.50° of chitosan coatings on Ti substrate.

Figure 9

ATR-FTIR spectrum of the chitosan coatings deposited on the Ti substrate.

Figure 10

The roughness profile of porous Ti and chitosan coatings obtained at 10 V for 30 min from different solutions.

Figure 11

Chitosan coatings microhardness (a) and Young’s modulus (b) vs. ethanol content in deposition solution.

Figure 12

Cell viability: for control sample images (a–c), for samples deposited from solution 1 (2% citric acid solution in 25% ethanol containing 1 g/dm³ of chitosan) at 10 V for 30 min: images (d–f), for samples deposited from starting solution (2% citric acid solution containing 1 g/dm³ of chitosan) at 10 V for 30 min: images (g–i).