Tomorrow is Today

Nanoparticle-Doped Stem Cells Allow Implantation With Real-time Feedback

Stem cell therapy uses cells that have the ability to transform into a wide variety of mature cell types. When implanted in the heart, for instance, they can transform into heart cells. This ability can be used to repair injured or diseased parts of the heart. Sadly, current methods of introducing stem cells rely on trial and error.

Let’s say, for instance, that a patient suffers a heart attack, which leaves some of his heart cells injured. To help the heart heal, the patient is first put into an MRI scanner to locate the areas of the heart that need repair. Once those are determined, doctors use the scan to implant new stem cells into these regions. After implantation, the patient is returned to the MRI to determine the location and number of implanted cells—if they’re not where they need to be, the patient is returned to surgery. This is exhaustively repeated.

Jesse Jokerst and colleagues at Stanford’s Bio-X lab… chose to approach the problem using ultrasound imaging… 

In the case of tiny stem cells, Jokerst had to use a contrast agent that would improve the resolution of ultrasound. For that, he developed silica nanoparticles, which, despite their very small size, can be detected by ultrasound. These nanoparticles are then embedded into stem cells prior to transplant. Their inclusion enables real-time footage of stem cells as they are injected…

This imaging technique… avoids the need for MRI, which “allows the entire procedure to be done in the operating room in real time. Thus, there is no need to move the patient because of the instant knowledge of cell location and number that ultrasound provides”. [Also], it makes the use of needle-mediated implantation easier than the less precise catheter-mediated method that inserts stem cells via the heart’s coronary artery.

…Jokerst [also] gave the nanoparticles two more properties. First, he linked them to a fluorescent dye, which he used to ensure that the nanoparticles were firmly embedded within the stem cells before implantation. Second, he doped the nanoparticles with gadolinium, which helps when the stem cells are imaged using an MRI scanner. Jokerst found that he could track the injected stem cells for up to two weeks after implantation by using an MRI scanner to follow the progress of the treatment.

(via Doctors track stem cells with nanoparticles during cardiac therapy | Ars Technica)

Researchers Manipulate Shape of Nanoparticles to Deliver Gene Therapy Without Viruses

Researchers from Johns Hopkins and Northwestern universities have discovered how to control the shape of nanoparticles that move DNA through the body and have shown that the shapes of these carriers may make a big difference in how well they work in treating cancer and other diseases.

This study is also noteworthy because this gene therapy technique does not use a virus to carry DNA into cells. Some gene therapy efforts that rely on viruses have posed health risks.

“These nanoparticles could become a safer and more effective delivery vehicle for gene therapy, targeting genetic diseases, cancer and other illnesses that can be treated with gene medicine,” said Hai-Quan Mao, an associate professor… in Johns Hopkins’ Whiting School of Engineering.

(via Shape coding replaces risky viruses in DNA nanoparticle therapy | KurzweilAI)

New Technique Lubricates Nanoparticles, Improving Ability to Penetrate Brain

Justin Hanes at Johns Hopkins University in Baltimore, Maryland, was surprised to discover just how impermeable brain tissue is to nanoparticles.

“It’s very sticky stuff,” he says, similar in adhesiveness to mucus, which protects parts of the body – such as the respiratory system – by trapping foreign particles.

It was thought that the adhesiveness of brain tissue limited the size of particles that can smoothly spread through the brain. Signalling molecules, nutrients and waste products below 64 nanometres in diameter can pass through the tissue with relative ease, but larger nanoparticles – suitable for delivering a payload of drugs to a specific location in the brain – quickly get stuck.

Now Hanes and his colleagues have doubled that size limit. They coated their nanoparticles with a densely-packed polymer shield, which lubricates their surface by preventing electrostatic and hydrophobic interactions with the surrounding tissue. “A nice hydrated shell around the particle prevents it from adhering to cells,” says Hanes.

(via Lubricated nanoparticles penetrate the brain - health - 29 August 2012 - New Scientist)

Nanoparticles Observed Self-Assembling Into Nanorods

Led by Haimei Zheng, a staff scientist in Berkeley Lab’s Materials Sciences Division, the researchers used a combination of transmission electron microscopy and advanced liquid cell handling techniques to carry out real-time observations of the growth of nanorods from nanoparticles of platinum and iron.

Their observations support the theory of nanoparticles acting like artificial atoms during crystal growth. “We observed that as nanoparticles become attached they initially form winding polycrystalline chains,” Zheng says. “These chains eventually align and attach end-to-end to form nanowires that straighten and stretch into single crystal nanorods with length-to-thickness ratios up to 40:1.

This nanocrystal growth process, whereby nanoparticle chains as well as nanoparticles serve as the fundamental building blocks for nanorods, is both smart and efficient.”

If the near limitless potential of nanotechnology is to even be approached, scientists will need a much better understanding of how nano-sized particles can assemble into hierarchical structures of ever-increasing organization and complexity. Such understanding comes from tracking nanoparticle growth trajectories and determining the forces that guide these trajectories.

(via Nanoparticles self-assemble into nanorods | KurzweilAI)

Fluorescent Nanoparticle Tattoo Checks Diabetics’ Glucose Levels Using iPhone

this injection of subdermal nanoparticles combines “fluorescent dye, specialized sensor molecules…and a charge-neutralizing molecule” that attach to glucose, releasing ions and altering the tat’s glow in the process.

The researchers had originally designed a “large boxlike” tattoo-reading device, but an apparent Apple fanboy on the team modded an iPhone case with LEDs and a filter lens to make the whole affair a bit more stylish. Next up for the team is, you guessed it, an app for that — although this one’ll focus on sodium.

(via Fluorescent nanosensor tattoo monitors glucose under the iPhone’s glare — Engadget)