Manufactured Nanomaterials (Fullerenes, C ₆₀ ) Induce Oxidative Stress in the Brain of Juvenile Largemouth Bass

Abstract

Although nanotechnology has vast potential in uses such as fuel cells, microreactors, drug delivery devices, and personal care products, it is prudent to determine possible toxicity of nanotechnologyderived products before widespread use. It is likely that nanomaterials can affect wildlife if they are accidentally released into the environment. The fullerenes are one type of manufactured nanoparticle that is being produced by tons each year, and initially uncoated fullerenes can be modified with biocompatible coatings. Fullerenes are lipophilic and localize into lipid-rich regions such as cell membranes in vitro, and they are redox active. Other nano-sized particles and soluble metals have been shown to selectively translocate into the brain via the olfactory bulb in mammals and fish. Fullerenes (C 60 ) can form aqueous suspended colloids (nC 60 ); the question arises of whether a redox-active, lipophilic molecule could cause oxidative damage in an aquatic species. The goal of this study was to investigate oxyradical-induced lipid and protein damage, as well as impacts on total glutathione (GSH) levels, in largemouth bass exposed to nC 60 . Significant lipid peroxidation was found in brains of largemouth bass after 48 hr of exposure to 0.5 ppm uncoated nC 60 . GSH was also marginally depleted in gills of fish, and nC 60 increased water clarity, possibly due to bactericidal activity. This is the first study showing that uncoated fullerenes can cause oxidative damage and depletion of GSH in vivo in an aquatic species. Further research needs to be done to evaluate the potential toxicity of manufactured nanomaterials, especially with respect to translocation into the brain. Two separate trials were performed using the same cohort of juvenile bass and the same batch of nC 60 . A total of 28 fish were randomly assigned to either exposure or control tanks over the course of the two trials (Table 1). Fish were exposed in groups of three or four in 10-L aquaria. The smaller trial consisted of fish in one aquarium each of control [reconstituted hard water (RHW), U.S. Environmental Protection Agency (EPA) protocol (U.S. EPA 1978), containing 192 mg/L sodium bicarbonate, 120 mg/L gypsum (CaSO 4 -2H 2 O), 120 mg/L magnesium sulfate, and 8 mg/L potassium chloride, pH 8.5] and 0.5 ppm nC 60 in RHW. The larger trial consisted of fish in two aquaria each of control, 0.5 ppm nC 60 , and 100 µM hydrogen peroxide (positive control for oxidative damage) and fish in one aquarium of 1 ppm nC 60 . Because of the high cost of production and limited quantities of nC 60 , I exposed fish in groups of either three larger fish (control and 0.5 ppm nC 60 ) or four smaller fish (1 ppm nC 60 ) per 10-L aquarium containing 7 L exposure water. To avoid aggressive interactions, I used smaller fish in the 1-ppm exposure aquaria to allow more space for individual fish. For aquaria with three fish, the fish were physically separated from one another with glass dividers. Vigorous aeration assured that water flowed freely between all three compartment...

Does nanoparticle activity depend upon size and crystal phase?

“…A key factor is that the building blocks, nanoparticles, have unique physicochemical properties and functionalities that are different from their bulk counterparts (Harman et al 2002;McDonald et al 2005). In recent years, there has been an increased concern about the potential of these nanoparticles to be emitted to the environment, followed by exposure of human beings and resultant adverse health effects (Biswas and Wu 2005;Oberdorster 2004;Wiesner et al 2006). There is supporting evidence of adverse health effects following exposure to nanoparticles present in the atmosphere and from combustion source emissions Donaldson et al 2001;Donaldson and Tran 2002;Penttinen et al 2001;Wichmann and Peters 2000).…”

Pristine (C60) and Hydroxylated [C60(OH)24] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

“…Buckministerfullerenes (fullerenes) are a class of carbon nanomaterials with biomedical, electronic, and semiconductor applications (1)(2)(3)(4). The potential environmental and health effects of fullerenes have attracted increasing attention in recent years (5)(6)(7)(8), especially with the development of water-soluble forms that facilitate their use in biological systems (3,9).…”

Nanoparticulate materials and regulatory policy in Europe: An analysis of stakeholder perspectives

“…Carbon nanotubes have been shown to cause granulomas in the lungs of animals, an immunological response to foreign objects (Lam et al, 2004;Warheit et al, 2004;Muller et al, 2005;Shvedova et al, 2005), and was found in one study to be more toxic than carbon black and quartz (Lam et al, 2004). Fullerenes have been shown in studies to be bioavailable when released in aqueous environments, cause lipid peroxidation in fishbrain (Oberdorster, 2004a) and inhibit bacterial growth (Fortner et al, 2005). Rendering the surface chemistry or coating may provide an attractive strategy in reducing toxicity.…”