No-Observed-Effect Level of Silver Phosphate in Carbonate Apatite Artificial Bone on Initial Bone Regeneration

Abstract

Fracture-related infections require both treatments for bacteria removal and bone reconstruction. The use of combined broad-spectrum antibacterial silver compounds and artificial bone with high osteogenic activity is considered to be an effective strategy for achieving these treatments in one surgery. However, silver compounds are toxic for living tissues even at low concentrations. Herein, we investigated the no-observed-effect level (NOEL) of silver phosphate (Ag3PO4) in a bone substitute composed of carbonate apatite (CO3Ap), a bone mineral, using in vitro and in vivo experiments. In vitro experiments demonstrated that the CO3Ap artificial bone containing ≥0.1 wt % Ag3PO4 exerted antibacterial effects against Staphylococcus epidermidis, while those containing ≤0.3 wt % Ag3PO4 did not affect cellular adhesion, proliferation, differentiation, and calcification of osteoblast-like MC3T3-E1 cells. In vivo experiments demonstrated that the CO3Ap artificial bone containing ≤0.3 wt % Ag3PO4 replaced a new bone to the same levels as those without Ag3PO4 4 weeks after implantation into the bone defect of the rabbit femur condyle. However, the CO3Ap artificial bone containing 0.3 wt % Ag3PO4 caused an inflammatory reaction, whereas those containing ≤0.1 wt % Ag3PO4 did not. Thus, both bone regeneration and infection control without any adverse effects were achieved using the CO3Ap artificial bone containing 0.1 wt % Ag3PO4, indicating that the NOEL of Ag3PO4 was 0.1 wt %. Our results provide an effective strategy for the treatments of fracture-related infections.

Effects of pore interconnectivity on bone regeneration in carbonate apatite blocks

“…As described in our previous work [ 45 ], MC3T3-E1 cells (Riken BioResource Center, Ibaraki, Japan) were maintained in a cell culture medium, which was an alpha modification of Eagle’s minimum essential medium (α-MEM; Gibco, USA) supplemented with 10% fetal bovine serum (Gibco), 100 U·cm −3 penicillin, 100 mg·cm −3 streptomycin and 0.25 mg·cm −3 amphotericin B (Gibco). The cells were incubated at 37°C in a humidified atmosphere containing 5% CO 2 .…”

A Review on the Recent Advancements on Therapeutic Effects of Ions in the Physiological Environments

“…Silver nanoparticles can secure the bacterial cell divider and, hence, enter it accordingly, causing underlying changes in the cell film like the eradication of the cell layer and demise of the cell, as shown in Figure 12B-D. There is the development of "pits" and the gathering of the nanoparticles on the cell surface [180][181][182][183].…”

“…Ag + particle is important for its valuable antimicrobial advantages in tissue culture functions [183]. Additionally, research has shown that the expansion of Ag tissue societies of in vitro bone does not meddle with markers of ontogenesis, for example, the creation of hydroxyapatite (HA) [183].…”

“…Ag + particle is important for its valuable antimicrobial advantages in tissue culture functions [183]. Additionally, research has shown that the expansion of Ag tissue societies of in vitro bone does not meddle with markers of ontogenesis, for example, the creation of hydroxyapatite (HA) [183]. Therefore, the joining of silver into tissues of bone recovery inserts could turn out to be useful by assisting the inhibition of diseases with insignificant injurious impacts.…”

“…Moreover, late discoveries have indicated that the openness of MC3T3-E1 cells to Ag-based nanoparticles brought about upregulation of bone development and guideline markers and quickened the separation and expansion of the cells [184]. Ag + particle is important for its valuable antimicrobial advantages in tissue culture functions [183]. Additionally, research has shown that the expansion of Ag tissue societies of in vitro bone does not meddle with markers of ontogenesis, for example, the creation of hydroxyapatite (HA) [183].…”