DNA-built nanostructures safely target, image cancer tumors

January 27th, 2014
A team of researchers at the University of Toronto has discovered a method of assembling "building blocks" of gold nanoparticles as the vehicle to deliver cancer medications or cancer-identifying markers directly into cancerous tumors. The study, led by Warren Chan, Professor at the Institute of Biomaterials & Biomedical Engineering (IBBME) and the Donnelly Centre for Cellular & Biomolecular Research (CCBR), appears in an article in Nature Nanotechnology this week.

"To get materials into a tumor they need to be a certain size," explains Chan. "Tumors are characterized by leaky vessels with holes roughly 50 – 500 nanometers in size, depending on the tumor type and stage. The goal is to deliver particles small enough to get through the holes and 'hang out' in the tumor's space for the particles to treat or image the cancer. If particle is too large, it can't get in, but if the particle is too small, it leaves the tumor very quickly."

Chan and his researchers solved this problem by creating modular structures 'glued' together with DNA. "We're using a 'molecular assembly' model - taking pieces of materials that we can now fabricate accurately and organizing them into precise architectures, like putting LEGO blocks together," cites Leo Chou, a 5th year PhD student at IBBME and first author of the paper. Chou was awarded a 2012-13 Canadian Breast Cancer Foundation Ontario Region Fellowship for his work with nanotechnology.

"The major advantage of this design strategy is that it is highly modular, which allows you to 'swap' components in and out. This makes it very easy to create systems with multiple functions, or screen a large library of nanostructures for desirable biological behaviors," he states.

The long-term risk of toxicity from particles that remain in the body, however, has been a serious challenge to nanomedical research.

"Imagine you're a cancer patient in your 30s," describes Chan. "And you've had multiple injections of these metal particles. By the time you're in your mid-40s these are likely to be retained in your system and could potentially cause other problems."

DNA, though, is flexible, and over time, the body's natural enzymes cause the DNA to degrade, and the assemblage breaks apart. The body then eliminates the smaller particles safely and easily.

But while the researchers are excited about this breakthrough, Chan cautions that a great deal more needs to be known.

"We need to understand how DNA design influences the stability of things, and how a lack of stability might be helpful or not," he argues.

"The use of assembly to build complex and smart nanotechnology for cancer applications is still in the very primitive stage of development. Still, it is very exciting to be able to see and test the different nano-configurations for cancer applications," Chan adds.

More information:
http://phys.org/news/2014-01-dna-strands-decomposable-nanostructures.html

Provided by University of Toronto

This Phys.org Science News Wire page contains a press release issued by an organization mentioned above and is provided to you “as is” with little or no review from Phys.Org staff.

More news stories

Plant cellulose prevents short circuits in batteries

(Phys.org)—In order to prevent short circuits in batteries, porous separator membranes are often placed between a battery's electrodes. There is typically a tradeoff involved, since these separators must simultaneously ...

Ultrasensitive sensor using N-doped graphene

A highly sensitive chemical sensor based on Raman spectroscopy and using nitrogen-doped graphene as a substrate was developed by an international team of researchers working at Penn State. In this case, doping refers to introducing ...

Historical records miss a fifth of global warming: NASA

A new NASA-led study finds that almost one-fifth of the global warming that has occurred in the past 150 years has been missed by historical records due to quirks in how global temperatures were recorded. The study explains ...

2016 climate trends continue to break records

Two key climate change indicators—global surface temperatures and Arctic sea ice extent—have broken numerous records through the first half of 2016, according to NASA analyses of ground-based observations and satellite ...

Weird quantum effects stretch across hundreds of miles

In the world of quantum, infinitesimally small particles, weird and often logic-defying behaviors abound. Perhaps the strangest of these is the idea of superposition, in which objects can exist simultaneously in two or more ...