Bharali et al that the probable dermal toxicity and morphological changes seen were due to accelerated oxidative stress in the skin after having been exposed to the SWCNT. Furthermore, in a sepa- rate study, the same group demonstrated that the exposure to unreﬁned SWCNT may lead to increased pulmonary toxicity due to oxidative stress.61 Other toxicity studies of carbon nanotubes describe the of cause granulomas in rats and mice after acute exposure.62 Crystalline silver nanoparticle-related cytoxicity in lesioned skin, growing human ﬁbroblasts, and keratinocytes was demonstrated by Lam and colleagues63 and Poon and Burd.64 These studies, among others, have begun to reveal the toxicity of nanoparticles and will pave the way for progression in this ﬁeld of study. Conclusion The biomedical application of nanoparticles has experienced exponential growth in the past few years; however, current knowledge regarding the safety of nanocarriers is insufﬁcient. As these new drug delivery systems are brought to clinical trial we will begin to be able to identify any negative side effects associated with these compounds. Preliminary and complemen- tary animal studies should be carried out to identify the risks associated with nanoparticle use, with particular attention paid to the elimination processes. Furthermore, very little attention has been paid to the environmental effects and the potential effects on the health of those manufacturing these particles. It is reported that only 1% of the total expenditure (US$1.2 billion) has been spent on occupational health and safety research of nanotechnology.65 Considering the countless potential appli- cations of nanoparticles in the health sector, particularly in cancer research, there is an urgent need for the development of safety guidelines by the government. 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