(Phys.org) —A number of years ago, a paper was published in Environmental Health Perspectives by Maureen Gwinn and Val Vallyathan that reflected concern about nanoparticles. Health experts ask: What are the long term health effects of nanoparticles? The authors wrote: “With the advent of nanotechnology, the prospects for using engineered nanomaterials with diameters of < 100 nm in industrial applications, medical imaging, disease diagnoses, drug delivery, cancer treatment, gene therapy, and other areas have progressed rapidly." They said that while potential for nanoparticles in these areas is infinite, possible toxic health effects associated with human exposure are unknown. This week, a technique that allows for the identification of nanoparticle distribution within mice simply looking at their skin has been reported which could be valuable in the search for answers.