Enhanced physicochemical and biological properties of C/Cu dual ions implanted medical titanium

Abstract

It is increasingly popular for titanium and its alloys to be utilized as the medical implants. However, their bio-inert nature and lack of antibacterial ability limit their applications. In this work, by utilizing plasma immersion ion implantation and deposition (PIII&D) technology, the titanium surface was modified by C/Cu co-implantation. The mechanical property, corrosion resistance, antibacterial ability and cytocompatibility of modified samples were studied. Results indicate that after C/Cu co-implantation, copper nanoparticles were observed on the surface of titanium, and titanium carbide existed on the near surface region of titanium. The modified surface displayed good mechanical property and corrosion resistance. The Cu/C galvanic corrosion existed on the titanium surface implanted by C/Cu dual ions, and release of copper ions can be effectively controlled by the galvanic corrosion effect. Moreover, improved antibacterial performance of titanium surface can be achieved without cytotoxicity.

Keywords: Antibacterial ability; Carbon; Copper; Ion implantation; Titanium.

Graphical abstract

Fig. 1

Morphology of surfaces at low magnification (a-d) and high magnification (e-f).

Fig. 2

C1s XPS high-resolution spectra gained from C–Ti and C/Cu–Ti surfaces (a and b) and inside at 30 nm depth (c and d); Cu 2p XPS high-resolution spectra gained from Cu–Ti and C/Cu–Ti surfaces (e and f) and inside at 30 nm depth (g and h).

Fig. 3

XPS high-resolution spectra of Ti 2p obtained from surfaces (a, c and e) and inside of C–Ti, Cu–Ti and C/Cu–Ti at 30 nm depth (b, d and f).

Fig. 4

Water contact angles measured from various surfaces.

Fig. 5

Cu²⁺ release curves from Cu–Ti and C/Cu–Ti immersed in PBS for two weeks.

Fig. 6

Polarization curves of various samples.

Fig. 7

Surface zeta potential values of different samples at various pH values.

Fig. 8

Hardness average values of various samples at the depth from 40 nm to 60 nm.

Fig. 9

Nano-hardness curves of various samples.

Fig. 10

Images of E. coli and S. aureus colonies on surfaces of different samples: E. coli (a) and S. aureus (b); Percent reductions of bacteria re-cultivated on agar: E. coli (c) and S. aureus (d). (*p < 0.05, **p < 0.01, ***p < 0.001).

Fig. 11

SEM morphology of E. coli seeded on different surfaces after incubation for 24 h.

Fig. 12

SEM morphology of S. aureus seeded on different surfaces after incubation for 24 h.

Fig. 13

Proliferative activity of MC3T3-E1 cultured on various surfaces for several days.

Fig. 14

Schematic diagram of possible antibacterial mechanism on titanium surface after C/Cu co-implantation.