Preventing Implant Bacterial Infections with Interconnected 3D Porous Structures (I3D)— A Proof-of-Concept Study

Abstract

Oral antibiotics are often prescribed to prevent infection after implant surgery; however, only a small fraction of the antibiotics can reach the implants. Thus, there are concerns about overusing antibiotics. We designed and fabricated porous implants with interconnecting 3D structures (I3D) and hypothesized that such I3D structures could serve as a depository for antimicrobial agents to prevent infection locally. The implants were either treated with antibiotics or coated with silver nanoparticles (AgNPs) by electrodeposition to test this hypothesis. The antimicrobial assay was conducted, and bacterial growth zones of inhibition (ZOIs) were monitored. Overall, I3D implants resulted in larger ZOIs than did the solid implants, and the center I3D (cI3D)-implant produced the largest ZOI. In the antibiotic treatment testing, the diameters of ZOIs of the solid implant vs. I3D implant were about 14 mm vs. 15 to 18 mm on day 2; however, the diameter quickly reduced to 9 mm on day 3 and 5 mm on days 6 and 8 for the solid implant, while no obvious change of the zone was seen for I3D implants. For the AgNPs coated implants, the ZOIs for the I3D implants were generally greater than the solid implant over four weeks of incubation. A significantly larger ZOI (~1-2 mm larger on average) was seen for AgNPs coated I3D implants at 0.1 V-0.01 M, 0.3 V-0.01 M, and 1.5 V-0.01 M treatments compared to AgNPs coated solid implants. Given that we have previously shown that I3D implants can reserve chemoattractants to recruit stem cells to enhance osseointegration, we conclude that implants with the I3D structures could be beneficial not only for osseointegration but also in preventing infection.

The overview of antimicrobial peptide‐coated implants against oral bacterial infections

“…• Reduced modulus of elasticity [33,39,42,44,45] F I G U R E 2 Different implant coating materials and strategies to prevent bacterial colonisation on implants include antibacterial polymers, [46,47] nanoparticles, [48,49] antimicrobial peptides (AMPs), [50][51][52] interconnecting 3D structures, [53] metal ions (Ag + , Cu 2+ , Sr 2+ or Zn 2+ ) [29,54,55] and antibiotics. [56][57][58] includes organic coatings (e.g., polymers, biomimetic films) and inorganic functional coatings (e.g., HA, titanium oxide) for osseointegration acceleration, bacteria adhesion reduction and biocompatibility improvement.…”

“…[33] Antimicrobial surface coating involves adding a layer on the implant's surface to either prevent bacteria adherence or kill bacteria by releasing antimicrobial chemicals or ions, or both. [33] To date, various coating materials have been applied to prevent bacteria from colonising the dental implant surface, such as antibacterial polymers, [46,47] nanoparticles, [48,49] AMPs, [50][51][52] interconnecting 3D structures, [53] metal ions (Ag + , Cu 2+ , Sr 2+ or Zn 2+ ) [29,54,55] and antibiotics (Figure 2). [56][57][58] Of these antimicrobial materials, AMPs have garnered considerable research attention for their broad spectrum of antimicrobial activity and their multi-modal mechanisms (advantages and disadvantages listed in Table 3).…”

“…Different implant coating materials and strategies to prevent bacterial colonisation on implants include antibacterial polymers, [ 46,47 ] nanoparticles, [ 48,49 ] antimicrobial peptides (AMPs), [ 50–52 ] interconnecting 3D structures, [ 53 ] metal ions (Ag + , Cu 2+ , Sr 2+ or Zn 2+ ) [ 29,54,55 ] and antibiotics. [ 56–58 ] …”

Antimicrobial Properties of Metal Nanoparticles and Their Oxide Materials and Their Applications in Oral Biology

“…After experiments, it was concluded that I3D implants can retain chemical attractants to recruit stem cells to enhance bone integration. Implants with I3D structure are not only conducive to bone integration but also help prevent infection [134]. Schoon et al demonstrated that titanium (Ti) surface binding with antibacterial silver nanoparticles (AgNPs) and lactoferrin (Lf) improved preosteoblast adhesion, proliferation, and differentiation while reducing bacterial colonization.…”