Gamers design swarms of nanoparticles for cancer research [with video]

NanoDoc (http://nanodoc.org) is a new online game to crowdsource the design of nanomedicine. It allows bioengineers and the general public to imagine nanoparticle strategies towards the treatment of cancer and test them on a virtual tumor. The challenge is to design nanoparticles that interact with each other and their environment in a way that leads to better treatment outcomes. The ultimate goal is to design nanoparticles that swarm like self-organized systems in nature. Best strategies will be tested using cancer-on-a-chip devices and large robotic swarms.

HFSP Cross-Disciplinary Fellow Sabine Hauert and colleagues authored on Thu, 26 September 2013

Cancer is the leading cause of death worldwide according to the WHO. To treat cancer, bioengineers are designing nanoparticles that can deliver drugs and therapeutics directly to tumors. Nanoparticles come in different sizes, shapes and materials. They can be loaded with drugs that are released in a controlled fashion, and coated with molecules that allow them to interact with their environment. Some of these molecules can serve as a signature to uniquely identify cancer cells.

As a result, there are many ways to design a nanoparticle. Depending on its design, the nanoparticle will move, sense and act in different ways in the tumor; changing the body of the nanoparticle will change its behavior. The challenge is to understand which nanoparticle designs will improve treatment outcome. This is a difficult problem because trillions of nanoparticles typically interact in a tumor with millions of cells. Predicting and optimizing the emergent behavior of all these nanoparticles is guess work at best.

To address this challenge, the Laboratory of Sangeeta Bhatia at MIT recently released an online game called NanoDoc (http://nanodoc.org) that allows bioengineers and the general public to imagine new nanoparticle strategies towards the treatment of cancer. It uses a realistic simulator developed at the laboratory to model how nanoparticles interact with each other and the tumor environment. The first levels of the game are used to train new NanoDocs; licensed NanoDocs are then given challenges to solve. Since its launch two weeks ago, the game has seen 10,000 visitors, 1750 players and over 40,000 simulations.

Figure: NanoDoc game to crowdsource the design of nanomedicine. The crowd designs nanoparticles and combines them into treatments (left). Treatments are then injected into a virtual tumor scenario designed by bioengineers (right). The goal is to discover ways in which nanoparticles can cooperate.

The longterm goal is to discover ways in which nanoparticles can cooperate, or swarm, like self-organized systems in nature. Select nanotreatments discovered using NanoDoc will be validated using

1. in vitro tissue-on-a-chip constructs designed to emulate the extravasation of functionalized nanoparticles from artificial vessels into a compartment containing tumor cells and 
2. robotic swarm systems in collaboration with Radhika Nagpal’s lab from the Wyss Institute at Harvard University.

http://nanodoc.org

Link to article in New Scientist

Link to article in Guardian

Tiny Diamonds Levitate in Wild Physics Experiment

ORIGINAL: LiveScience
By Laura Poppick, Staff Writer

August 14, 2013

Researchers have used lasers to levitate extremely small particles in the past, such as individual atoms, but this is the first time that anyone has ever levitated a nanodiamond. Credit: J. Adam Fenster/University of Rochester.

In quite an eerie feat, physicists have floated microscopic diamonds in midair using laser beams.

Researchers have already used lasers to levitate extremely small particles, such as individual atoms, but this is the first time that the technique has worked on a nanodiamond, which, in this case, measures just 100 nanometers (3.9 x 10-8 inches) across, or more than 1,000 times thinner than a fingernail.

In the new study, the physicists from the University of Rochester relied on the fact that a laser beam, which is made up of photons, creates a tiny force that usually can't be felt. [Wacky Physics: The Coolest Little Particles in Nature]

"If we turn on a light or open a door and feel the sun, we don't feel this push or pull," study researcher Nick Vamivakas said in a video released by the university. "But it turns out that if you focus a laser down with a lens to a very small region of space, it can actually pull on microscopic, nanoscopic particles."

To force the tiny diamonds to float, Vamivakas and his colleagues focused a pair of lasers toward a clear vacuum chamber and then sprayed the diamonds into the chamber using an aerosol dispenser. The diamonds gravitated toward the light, and some eventually levitated in a stable position.

Sometimes, the levitation occurred within just a couple of minutes, while other times, the process took a bit longer.

"Other times, I can be here for half an hour before any diamond gets caught," Levi Neukirch, a graduate student at the University of Rochester who was involved in the study, said in a statement. "Once a diamond wanders into the trap, we can hold it for hours."

The team hopes the findings will have applications in quantum computing and, more theoretically, help explain how friction operates on extremely small scales.

"The position of the crystal in the trap is a very sensitive probe of forces in its environment," Vamivakas said in the university video. "The reason this is important is, as technology continues to shrink down to these length scales, we need to understand how the environment will interact with the devices that we are making."

The team plans to continue its experiments in order to better understand the physical behavior of the crystals, which could help address other basic unanswered questions in physics.

The levitation experiment is detailed this week in the journal Optics Letters.

Follow Laura Poppick on Twitter. Follow LiveScience on Twitter, Facebook and Google+. Original article on LiveScience.

Oh, My Stars and Hexagons! DNA Code Shapes Gold Nanoparticles

ORIGINAL: Science Daily

University of Illinois chemists found that DNA can shape gold nanoparticle growth similarly to the way it shapes protein synthesis, with different letters of the genetic code producing gold circles, stars and hexagons. (Credit: Li Huey Tan, Zidong Wang and Yi Lu)

ScienceDaily (Aug. 8, 2012) — DNA holds the genetic code for all sorts of biological molecules and traits. But University of Illinois researchers have found that DNA's code can similarly shape metallic structures.

The team found that DNA segments can direct the shape of gold nanoparticles -- tiny gold crystals that have many applications in medicine, electronics and catalysis. Led by Yi Lu, the Schenck Professor of Chemistry at the U. of I., the team published its surprising findings in the journal Angewandte Chemie.

"DNA-encoded nanoparticle synthesis can provide us a facile but novel way to produce nanoparticles with predictable shape and properties," Lu said. "Such a discovery has potential impacts in bio-nanotechnology and applications in our everyday lives such as catalysis, sensing, imaging and medicine."

Gold nanoparticles have wide applications in both biology and materials science thanks to their unique physicochemical properties. Properties of a gold nanoparticle are largely determined by its shape and size, so it is critical to be able to tailor the properties of a nanoparticle for a specific application.

"We wondered whether different combinations of DNA sequences could constitute 'genetic codes' to direct the nanomaterial synthesis in a way similar to their direction of protein synthesis," said Zidong Wang, a recent graduate of Lu's group and the first author of the paper.

Gold nanoparticles are made by sewing tiny gold seeds in a solution of gold salt. Particles grow as gold in the salt solution deposits onto the seeds. Lu's group incubated the gold seeds with short segments of DNA before adding the salt solution, causing the particles to grow into various shapes determined by the genetic code of the DNA.

The DNA alphabet comprises four letters: A, T, G and C. The term genetic code refers to the sequence of these letters, called bases. The four bases and their combinations can bind differently with facets of gold nanoseeds and direct the nanoseeds' growth pathways, resulting in different shapes.

In their experiments, the researchers found that strands of repeating A's produced rough, round gold particles; T's, stars; C's, round, flat discs; G's, hexagons. Then the group tested DNA strands that were a combination of two bases, for example, 10 T's and 20 A's. They found that many of the bases compete with each other resulting in intermediate shapes, although A dominates over T.

Next, the researchers plan to investigate exactly how DNA codes direct nanoparticle growth. They also plan to apply their method to synthesize other types of nanomaterials with novel applications.