Categories
Uncategorized

Molecular Shape

At the nanometer scale, the free radical scavenging properties of cerium oxide are even further enhanced, because of the dramatic increase in surface area.Oxygen vacancies, and their potential for interactions with free radicals, form more readily at the nanoscale.The radical scavenging ability of cerium oxide appears to be dramatically increased during the reduction to the nanoscale.Free radicals, when produced intracellularly, can strip electrons from biomolecules such as proteins and lipids, causing considerable damage to cellular constituents.Unlike materials, biological organisms have innate mechanisms for coping with free radical production, which are the subject of several excellent reviews.However, organism aging and disease often overtax the system and free radical generation exceeds the antioxidant capacity, resulting in a state termed oxidative stress.Being the most oxidative organ in the body, the brain and central nervous system are sites of heavy free radical production and hence high oxidative stress.Yet to date, use of antioxidants in abolishing these pathological conditions has met with only limited success.Our Diclofenac Potassium traditional pharmacological antioxidants require multiple dosing, because the free radical scavenging of each antioxidant molecule is usually limited to one free radical.Moreover, distribution of antioxidants is often limited to specif ic cellular sites, which may not necessarily coincide with the localized sites of free radical damage.In our prior studies using an in vitro model of traumatic brain injury, our laboratory routinely prepared mixed cultures of cortical brain cells, comprising neurons and glia.When removed from the rat, most primary mixed cortical brain cell cultures remain healthy and viable for an Flunixin meglumin average of days.Panel B shows a culture from the same preparation batch, treated with nM cerium oxide nanoparticles once, on day in vitro.Note the robust cellular network and many processed neurons.Bottom panel: DIV culture treated with nM cerium oxide nanoparticles at DIV.As we have previously shown, this exposure period resulted in cellular uptake of ceria nanoparticles, as shown by electron microscopy.Hence, it appears that one dose was incorporated intracellularly and provided prolonged effects.In further support for an antioxidant role for ceria, we found that ceriatreated cultures maintained higher levels of catalase and reduced glutathione during the lifespan, compared with untreated controls, suggesting that ceria treatment either preserved or added to innate cellular radical scavenging systems.Recently, we conf irmed the radical scavenging activity of cerium oxide nanoparticles in vitro.Using electron paramagnetic resonance, we found that cerium oxide nanoparticles did not produce free radicals in vitro and were excellent scavengers of both superoxide and hydroxyl radicals. In doseresponse studies, we found that nM concentrations produced optimum radical scavenging and longevity enhancing effects.However, the doseresponse curve was bell shaped, with doses lower than nM and higher than M having reduced benef icial effects. Thisfinding is expected, because recent literature suggests that a basal level of free radical production is necessary for normal cell signaling, which indicates that excessive or repeated doses of ceria may have negative effects.During free radical challenge with mM glutamate, the nanoparticles afforded signif icant antioxidant protection and increased cell survival.Using the free radical indicator dye dichlorofluorescein diacetate, the group demonstrated that nanoparticles could decrease free radical production.

Leave a Reply

Your email address will not be published. Required fields are marked *