The application of
gold nanoparticle-
peptide conjugates as
theranostic agents for
colorectal cancer shows much promise. This study aimed at determining the neurotoxic impact of 14 nm
gold nanoparticles (AuNPs) functionalized with
colorectal cancer-targeting
peptides (namely p.C, p.L or p.14) in a rat model. Brain tissue samples, obtained from Wistar rats that received a single injection of
citrate-capped AuNPs,
polyethylene glycol-coated (PEG) AuNPs, p.C-PEG-AuNPs, p.L-PEG-AuNPs or p.14-PEG-AuNPs, and sacrificed after 2- and 12-weeks, respectively, were analysed.
Inflammation marker (tumour
necrosis factor-α,
interleukin-6,
interleukin-1β), oxidative stress (
superoxide dismutase,
catalase,
glutathione peroxidase) and apoptotic
biomarker (
cytochrome c,
caspase-3) levels were measured.
Gold nanoparticle-treated groups sacrificed after 2-weeks did not exhibit any significant inflammatory, oxidative stress or apoptotic effects in brain tissue compared to the untreated control group. In brain tissue from rats that were exposed to
citrate-capped AuNPs for 12-weeks, tumour
necrosis factor-α and
interleukin-6 levels were significantly increased compared to the untreated control. Exposure to PEG-AuNP, p.C-PEG-AuNP, p.L-PEG-AuNP and p.14-PEG-AuNP did not elicit significant toxic effects compared to the control after 12-weeks, as evidenced by the absence of inflammatory, oxidative stress and apoptotic effects in brain tissue. We thus report on the safety of PEG-coated AuNP-
peptide conjugates for potential application in the diagnosis of
colorectal cancer; however, exposure to
citrate-capped AuNPs could induce delayed neuro-
inflammation, and as such, warrants further investigation.