Polymeric nanoparticle–aptamer bioconjugates can diminish the toxicity of mercury in vivo

► We synthesize a polymeric nanoparticle–aptamer for drug delivery. ► Nanoparticle–aptamer diminishs the toxicity of mercury. ► Nanoparticle–aptamer induces little toxicity. ► Pharmacology involves slow drug release, toxicant antagonism and enzyme protection. Targeted delivery drugs by nanoparticles and aptamers is a hot issue; however, the application to ameliorate toxicity of toxicants is unknown, and the information about nanoparticle–aptamer toxicology and pharmacology is limited. In this work, nanoparticle–aptamer was synthesized and then its toxicological and pharmacological information was studied. Mercury was selected as a model toxicant and the antidote was entrapped by nanoparticle–aptamer. The nanoparticle–aptamer with a suitable size of 120 nm avoided aptamer biodegradation and achieved an effective release of antidote. Rats were orally administered mercury-contaminated rice and then nanoparticle–aptamer was intravenously injected. The nanoparticle–aptamer markedly reduced the quantity of mercury in both the brain and kidney, and enhanced the excretion of urinary mercury. Water Maze and Open Field tests showed that nanoparticle–aptamer ameliorated the neurotoxicity and improved the learning and memory of rats. The pharmacology of nanoparticle–aptamer involved slow antidote release, antidote-toxicant antagonism, enhancement of crucial enzymes activity and decreased lipid peroxidation. Toxicology of nanoparticle–aptamer was also studied by hematologic tests (creatinine, urea, red and white blood cell), and exhibited little toxicity. Nanoparticle–aptamer can diminish the toxicity of mercury in vivo with few adverse effects, and is a potential tool in reducing the hazards of toxicants to human health.