Nanoparticles affect bacterial colonies' optical diffraction patterns.

It is increasingly being accepted that bacteria are able to alter their shape/colony pattern in response to adverse environmental conditions. Morphological adaptation of bacteria is known as one of their defence mechanisms against environmental stress/variations. As nanoparticles (NPs) have a unique capacity to induce a wide range of stresses to bacteria, we hypothesized that such NPs can affect the bacterial colony pattern. To test this hypothesis, we incubated a series of superparamagnetic iron oxide nanoparticles (SPIONs) with different physicochemical properties with bacterial colonies and probed the colonies' diffraction patterns by laser. The diffraction patterns of Escherichia coli, Lactobacillus rhamnosus, and Staphylococcus aureus colonies were recorded using a laser. Our results revealed the formation of distinct bacterial diffraction patterns in response to SPIONs with various concentrations and surface chemistries. Our results may pave the way toward the development of new optical approaches for the high-throughput screening of bacterial-NPs/drugs interactions.

Effects of prenatal exposure to single-wall carbon nanotubes on reproductive performance and neurodevelopment in mice.

Carbon nanotubes with extraordinary properties may become a novel drug and gene delivery tool in nanomedicine; however, insufficient information is available regarding their biosafety. Therefore, this work was performed to study the effect of prenatal exposure of single-walled carbon nanotubes (SWCNTs) on reproductive and neurobehavioral endpoints in mice. Thirty pregnant female mice were assigned to three groups (n = 10 for each group). The two treated groups were injected intraperitoneally (i.p.) with 1 or 10 mg/kg body weight (b.w.) of SWCNTs suspended in 1 ml of phosphate buffer saline (PBS) on gestational days 0 and 3. The control group was injected i.p. with an equal volume of PBS. The neurobehavioral ontogeny of pups was evaluated using a modified Fox battery. A decrease in litter size on postnatal day 2 was observed in the group treated with 10 mg/kg b.w. of SWCNTs whereas no significant differences between groups were observed in any other parameters. The behavioral development of pups did not show significant differences during growth except for the surface righting reflex, which showed significant delay compared to control in the group treated with 1 mg/kg b.w. SWCNTs. Moreover, exposed offspring (10 mg/kg b.w. SWCNTs) displayed enhanced anxiety in the elevated plus maze; however, other ethological analysis (Morris water maze and open field test) did not show behavioral changes in the experimental groups. In conclusion, the present results demonstrated small changes in offspring sensory and motor development following exposure to SWCNTs and support the idea that SWCNT risk assessment merits further investigation.

Biosafety of multiwalled carbon nanotube in mice: a behavioral toxicological approach.

Multiwalled carbon nanotubes (MWCNTs) with unique chemical and electromechanical properties are ideal candidates for the development of drug delivery platforms. The scarce knowledge for the effects of exposure to MWCNTs during pregnancy on postnatal outcomes motivated us to investigate whether intraperitoneal injections (i.p.) of MWCNTs during mating and early pregnancy affect on reproductive and neurobehavioral endpoints and psychobiological status of pups. Thirty virgin female mice were divided to three groups (n = 10 for each); two treated groups injected i.p. with 1 and 10 mg of MWCNTs suspended in 1 ml of phosphate buffered saline solution (PBS) in both mating day and gestation day 3, respectively. The control group was injected i.p. with an equal volume of PBS as a vehicle. MWCNT-treated dams did not exhibit considerable changes in their reproductive performance in gestation and lactation periods. MWCNT-treated pups exhibited similar ontogenetic expressions of neurobehavioral and physical endpoints as compared with control group. Most notably, exposure to MWCNTs was increased depressive and anxious behaviors of treated pups in parallel to adverse effect on their internal organ weights. The absolute thymus weight was declined in MWCNT-treated groups while absolute weights of liver and spleen decreased in group treated by 1 mg of MWCNT as compared to control group. Relative organ weights in MWCNT-treated groups were almost similar to control group.