Researchers at the University of California have created tiny flakes of silicon that glow brightly and illuminate tumors for a longer time to ensure better drug delivery.
The nano-scale material glows brightly, last long enough to slowly release cancer drugs, and then break down into harmless by-products.
The authors said that it's the first study to image tumors and organs using biodegradable silicon nano particles in live animals.
"It is the first luminescent nanoparticle that was purposely designed to minimize toxic side effects," Nature magazine quoted Michael Sailor, a chemistry professor at UCSD who led the study, as saying.
While many nanoparticles tested in research labs are too poisonous for use in humans, "this new design meets a growing need for non-toxic alternatives that have a chance to make it into the clinic to treat human patients," said Sailor.
While testing the safer nanoparticles in mice, the researchers found that tumors glow for several hours, and then dim as the particles broke down.
Also it was found that levels dropped noticeably in a week and were undetectable after four weeks.
Initially, the particles are thin wafers made porous with an electrical current and then smashed to bits with ultrasound.
With additional treatment, the physical structure of the flakes is altered to make them glow red when illuminated with ultraviolet light.
Luminescent particles can reveal tumors too tiny to detect by other means or allow a surgeon to be sure all of a cancerous growth has been removed.
Also, the researchers claimed that these nanoparticles could help deliver drugs safely. The cancer drug doxorubicin will stick to the pores and slowly escape as the silicon dissolves.
"The goal is to use the nanoparticles to chaperone the drug directly to the tumor, to release it into the tumor rather than other parts of the body," said Sailor.
Targeted delivery would allow doctors to use smaller doses of the drug. At high doses doxorubicin often has toxic side effects.
The particles, at about 100 nanometers, are bigger than many designed to deliver drugs, and thus they tend to be more effective and safe.
Large particles can hold more of a drug. Yet they self-destruct, and the remnants can be filtered away by the kidneys.
After examining vulnerable organs like liver, spleen and kidney, which help to remove toxins, scientists discovered no lasting changes in mice treated with the new nanoparticles.
The study has been published in Nature Materials.