A three-dimensional magnetically driven microrobot can carry and deliver cells to targeted areas in vivo.

The impact of carbon nanotubes (CNTs) on the aquatic environment was investigated by examining the properties of raw CNTs under several environmental conditions and using developing zebrafish (Danio rerio) embryos. The agglomerate size for single‐walled CNTs (SWCNTs) was significantly larger at pH 11 or greater and was stable at temperatures from 4 to 40°C and salinities from 0 to 30 ppt. Exposure to SWCNTs induced a significant hatching delay in zebrafish embryos between 52 to 72 h postfertilization (hpf) at concentrations of greater than 120 mg/L, but 99% of the exposed embryos hatched by 75 hpf. Double‐walled CNTs also induced a hatching delay at concentrations of greater than 240 mg/L, but carbon black did not affect hatching at the concentrations tested. Molecular and cellular analysis showed that the embryonic development of the exposed embryos up to 96 hpf was not affected at SWCNT concentrations of up to 360 mg/L. Scanning‐electron microscopic inspection showed that the size of the pores on the embryo chorion was nanoscaled and that the size of SWCNT agglomerates was microscaled or larger, indicating that the chorion of zebrafish embryos was an effective protective barrier to SWCNT agglomerates. The hatching delay observed in this study likely was induced by the Co and Ni catalysts used in the production of SWCNTs that remained at trace concentrations after purification. This study suggests that materials associated with raw SWCNTs (perhaps metal contaminants) have the potential to affect aquatic life when released into the aquatic environment.

Phthalates, widely used in flexible plastics and consumer products, have become ubiquitous contaminants worldwide. This study evaluated the acute toxicity and estrogenic endocrine disrupting activity of butyl benzyl phthalate (BBP), di(n-butyl) phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), diisononyl phthalate (DINP), di-n-octyl phthalate (DNOP) and their mixtures. Using a 72 h zebrafish embryo toxicity test, the LC₅₀ values of BBP, DBP and a mixture of the six phthalates were found to be 0.72, 0.63 and 0.50 ppm, respectively. The other four phthalates did not cause more than 50% exposed embryo mortality even at their highest soluble concentrations. The typical toxicity symptoms caused by phthalates were death, tail curvature, necrosis, cardio edema and no touch response. Using an estrogen-responsive ChgH-EGFP transgenic medaka (Oryzias melastigma) eleutheroembryos based 24 h test, BBP demonstrated estrogenic activity, DBP, DEHP, DINP and the mixture of the six phthalates exhibited enhanced-estrogenic activity and DIDP and DNOP showed no enhanced- or anti-estrogenic activity. These findings highlighted the developmental toxicity of BBP and DBP, and the estrogenic endocrine disrupting activity of BBP, DBP, DEHP and DINP on intact organisms, indicating that the widespread use of these phthalates may cause potential health risks to human beings.