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International Journal of Bioprinting 3D printing innovations against infection

loaded with specific cells during the 3D printing process They assessed the antimicrobial activity of the HA
to promote bone regeneration while preventing bone coating containing 3% silver against methicillin-resistant
infection (Figure 4D). (v) Physical signals (e.g., magnetic Staphylococcus aureus (MRSA) in vitro using an animal
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field, electric field, and infrared light) stimulation can be model. The results demonstrated that this Ag-HA coating
loaded to promote bone tissue growth while resisting efficiently released silver ions, effectively eliminating
3D implants infection, and effectively treating bone MRSA in vivo, thus exhibiting outstanding antimicrobial
defects (Figure 4E). (vi) Growth factors (e.g., VEGF, properties. Simultaneously, Akiyama et al. 108 explored
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FGF, and PVDF) can be incorporated into the 3D-printed the sterilizing effect of silver-loaded hyaluronic acid-
scaffolds to promote the construction of vessels in bone coated titanium dioxide in the bone marrow cavity of rat
defects while resisting orthopedic infection (Figure 4F). tibia. The study revealed a significant reduction in the
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Representative strategies to prevent infection and control bacterial count in the silver-containing hyaluronic acid-
bacterial adhesion are discussed in this section. coated group compared to the hyaluronic acid-coated
group alone. Furthermore, the long-term antimicrobial
4.1.1. Incorporating antimicrobial nanoparticles effect of silver ions was corroborated through a 4-week
into 3D-printed scaffolds imaging assessment. Collectively, these studies underscore
Silver coatings, in various forms, stand out as the most the potential of applying silver ions in various materials
frequently utilized inorganic molecular coatings in the to effectively inhibit bacterial growth and mitigate the
realm of antimicrobial applications. The utilization of development of infections.
silver has progressed from its ionic form in silver nitrate
or in combination with antimicrobial sulfonamides, In the realm of bone tissue engineering, the necessity
such as silver sulfadiazine, to the incorporation of for advanced 3D porous scaffolds that address bone
nanoparticle (NP) forms for applications in implant infection defects and facilitate new bone regeneration
coatings or dressings. 105,106 Shimazaki et al. employed remains urgent. Ideally, these scaffolds should boast
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an innovative thermal spraying technique to amalgamate exceptional attributes, encompassing mechanical strength,
the potent antibacterial properties of silver (Ag) with biodegradability, optimal porosity, and biocompatibility
hydroxyapatite (HA), known for its high biocompatibility (Table 1). 109,110 When implanted in vivo, such scaffolds can
and osteoconductive properties, forming a robust bond. instigate bone tissue growth and foster osseointegration.

Table 1. Three-dimensional printing of antimicrobial materials in orthopedic implants

Antimicrobial Author Benefits Materials 3D printer Ref.
Appropriate mechanical,
Correia et al. TCP and SA scaffold Rapid prototyping 111
biocompatibility, and bactericidal
Deng et al. Osteogenesis and antibacterial PEEK FDM 112
Nanoparticles Antimicrobial and bone
Li et al. nAg/PDA/PCL Stents FDM 102
regeneration
Good osteogenic and
Li et al. sp-EMS scaffold 3D design 104
antimicrobial effects
Reduced bacterial infection of
Inzana et al. Rifampin- and vancomycin-laden CPS 3D inkjet 117
implants
Good biocompatibility and a
Zhou et al. sustained antibacterial effect Vancomycin-loaded PCL/PDA/PLGA FDM 118
Drug loading
He et al. Good biocompatibility and TCDMDA stent 3D inkjet 21
antimicrobial
Stronger, more brittle, more stable,
Kim et al. PLA liner 3D design 95
and better at eluting antibiotics
Stronger mechanical behavior and
Tripathi et al. antimicrobial properties and lower Cu-HA scaffolds 3D Extrusion 122
Others toxicity
Cometta et al. Inhibits biofilm formation in vitro Melamine-modified 3D-printed PCL scaffolds 3D design 130
Abbreviations: CPS, calcium phosphate scaffold; FDM, fused deposition modeling; HA, hydroxyapatite; PEEK, polyether ether ketone; PCL,
polycaprolactone; PDA, polydopamine; PLA, polylactic acid; PLGA, poly-lactic acid-glycolic acid; SA, sodium alginate; sp-EMS, self-promoting
electroactive mineralized scaffold; TCDMDA, tricyclodecanedimethanol diacrylate; TCP, tricalcium phosphate.

Volume 10 Issue 4 (2024) 131 doi: 10.36922/ijb.2338