The interaction between TiO₂-NP and inflammatory cytokines, including CXCL8, a clinically relevant pro-inflammatory chemokine, was also investigated by Batt et al.. The authors found that the TiO₂-NP could preferentially adsorb CXCL8 (and IFN-γ), which leads to the disruption of neutrophil chemotaxis and modifies local inflammatory mediator concentration and might result in hampered inflammatory response.

The potential risks of TiO2 accumulation in the body have been followed by reports of metal debris from titanium prosthesis wear. According to Engh et al.’s report, the accumulation of metal debris such as titanium, aluminum, and vanadium was found in the bone marrow of two patients who had implanted joints in the iliac. One of the two patients was diagnosed with leukocytopenia, anemia, and general weakness. Although it is questionable that whether these conditions were due to an accumulation of titanium toxicity or not, attention needs to be paid to the fact that metal debris from worn out implants can accumulate in the liver, spleen, and bone marrow, causing adverse effects on the body and systemic disease.

Toxicity of titanium alloy

Titanium alloys have many applications in medical implantation, including orthopedic prostheses and dental implant. Various studies have been conducted regarding the effects of metal particles which worn out from orthopedic prostheses. In 1981, Rae performed experiments in which human synovial fibroblasts were exposed to various preparations of metals and alloy, including pure titanium and wear debris from titanium alloy (Ti-6Al-4V). In the experiment conditions, fibroblasts incubated with pure titanium and titanium alloy showed no significant increases in lactate dehydrogenase and no morphological change. Besides, due to the high solubility of vanadium in the cultured cells, the author estimated that the vanadium from titanium alloy might be potentially harmful to the cell.