Glowing dots used in cancer diagnosis?

(Image: Wikimedia Commons)

The US Food and Drug Administration (FDA) has approved the first clinical trial in humans of a new technology: Cornell Dots, brightly glowing nanoparticles that can light up cancer cells in PET-optical imaging.

A paper describing this new medical technology, "Multimodal silica nanoparticles are effective cancer-targeted probes in a model of human melanoma," were published 13 June 2011 in the Journal of Clinical Investigation (July 2011). This is a collaboration between Memorial Sloan-Kettering Cancer Centre (MSKCC), Cornell University, and Hybrid Silica Technologies, a Cornell business start-up.

For the first time, scientists report a uniquely advanced and comprehensive characterisation of Cornell Dots - an ultra small, cancer-targeted, multimodal silica nanoparticle - which has recently been approved as an "investigational new drug" (IND) by the FDA for a first-in-human clinical trial, says Michelle S. Bradbury, M.D., of the Memorial Sloan-Kettering Cancer Centre and an assistant professor of radiology at Weill Cornell Medical College.

A guiding light within the body

Cornell Dots are silica spheres less than 8 nanometres in diameter that enclose several dye molecules. (A nanometre is one-billionth of a metre, about the length of three atoms in a row.) The silica shell, essentially glass, is chemically inert and small enough to pass through the body and out in the urine. For clinical applications, the dots are coated with polyethylene glycol (PEG) so the body will not recognise them as foreign substances.

A guiding light within the body: To make the dots stick to tumour cells, organic molecules that bind to tumour surfaces or even specific locations within tumours can be attached to the PEG shell. When exposed to near-infrared light, the dots fluoresce much brighter than dye to serve as a beacon to identify the target cells. The technology, the researchers say, enables visualisation during surgical treatment, showing invasive or metastatic spread to lymph nodes and distant organs, and can show the extent of treatment response.

The first FDA IND approved inorganic particle platform of its class and properties

Hooisweng Ow, a co-author of the paper and once a graduate student working with Ulrich Wiesner, Cornell Professor of Materials Science and Engineering, developed first-generation Cornell dots in 2005. Together, Wiesner, Ow and Kenneth Wang, have co-founded the company Hybrid Silica Technologies (HST) to commercialise the invention. The combined team of MSKCC, Cornell and HST researchers is now in the process of forming a new commercial entity in New York City that will help transition the research into commercial products that will benefit cancer patient care.

"This is the first FDA IND approved inorganic particle platform of its class and properties that can be used for multiple clinical indications, two of which are explored: cancer targeting for diagnostics and future therapeutic diagnostics, as well as cancer disease staging and tumour burden assessment via lymph node mapping," says Bradbury.

The Cornell Dots were optimised for efficient renal clearance, allowing the body to pass them through the kidneys.

In addition, the scientists were able to perform real-time imaging of lymphatic drainage patterns and particle clearance rates, as well as sensitively detect nodal metastases. Nodal mapping is now being pursued under a new award of a BioAccelerate NYC Prize from the Partnership for New York City and the New York City Economic Development Corporation, which is expected to lead to another clinical trial in humans.

The lead authors of the paper are Miriam Benezra and Oula Penate-Medina, who are researchers are at MSKCC. Bradbury and Wiesner are the senior authors.