TABLE 2.

Recent development of antibacterial coatings on titanium implants

Categories	Main anti-infection agent	Mentioned synthesis method	Included bacteria species	Antibacterial effects	References
Metal ions	AgNPs	Physical vapor deposition (PVD)	S. aureus, S. mutans, S. epidermidis, E. coli, P. aeruginosa	↑Antibacterial effect	Lampé et al. (2019)
		Electron cyclotron resonance (ECR)			Chen et al. (2016)
		In situ dopamine reduction			Guo et al. (2020)
		Layer-by-layer assembly			Wang et al. (2021b)
		Electrodeposition			Ren et al. (2021)
		Thermochemical treatment			Rodríguez-Contreras et al. (2021)
	Zn	MAO	S. aureus	↑Antibacterial effect	Ye et al. (2020)
		Electrodeposition	E. coli		Shahmohammadi and Khazaei (2021)
		Hydrothermal method	P. gingivalis		Chen et al. (2021b)
	Cu	—	MRSA	↓Biofilm formation, virulence	Zhuang et al. (2021)
				↓Antibiotic resistance of MRSA
	Ga	Hydrothermal method	S. aureus	Strong antibacterial ability	Li et al. (2021b)
			E. coli
	AgNPs	Laser cladding	S. aureus	Long-term synergistic antibacterial activity of Zn2+ and Ag+	Zhang et al. (2018b)
	Zn2+		E. coli
	AgNPs	Plasma electrolytic oxidation	MRSA	Synergistic antibacterial activity of Ag and Cu	van Hengel et al. (2020b)
	CuNPs
Non-metallic antibacterial substances	Iodine	Anodization	S. aureus	↓Bacterial colonization	Shirai et al. (2011)
			E. coli
	Chlorhexidine	Organosilane chemistry	S. aureus	↓Bacteria adhesion and growth	Wang et al. (2019)
Anti-fouling coatings	PEG	Simultaneous deposition; electrodeposition	S. aureus	↓Protein absorption	Guo et al. (2021)
			E. coli	↓Bacterial and platelet adhesion	Hoyos-Nogués et al. (2018)
			S. sanguinis	↓Biofilm formation
	Zwitterionic copolymer	Free radical polymerization	E. coli	↓Protein adsorption, platelet adhesion	Huang et al. (2017)
		RAFT polymerization		↓Bacteria adhesion
Light-induced ROS	Photodynamic-induced ROS	Plasma electrolytic oxidation	S. sanguinis, A. naeslundii	↑Antibacterial effect in light conditions	Nagay et al. (2019)
				↑Degradation efficiency of lipopolysaccharide	Wu et al. (2019)
	Photothermal-induced ROS	π-π stacking	S. aureus, MRSA	↑Bacteria killing	Yuan et al. (2019)
		Hydrothermal method		↓Biofilm formation	(Song et al., 2020)
		EDC-NHS chemistry			Su et al. (2020)
		Sulfur doping
Bioactive antibacterial agent	AMP	Organosilane chemistry, click chemistry	S. gordonii, S. aureus	↑Antibiofilm activity	Acosta et al. (2020)
		Layer-by-layer assembly			Rodríguez López et al. (2019)
Intelligent controlled release antibacterial coating	Gentamicin	—	S. aureus	↓Bacteria growth and adhesion	Sang et al. (2021)
			E. coli	↑Bacteria killing in a slightly acidic environment
	Glycerin	Anodization	S. aureus	↑Immunoregulatory antibacterial activities at 40°C	Li et al. (2021a)
			E. coli