How To Detect Nuclear Device

How to keep U.S. ports of entry safe and secure by detecting and interdicting illicit radioactive or nuclear materials? A team led by Northeastern’s Swastik Kar and Yung Joon Jung has developed a technology that could go a long way toward achieving that goal.

nuclear radiation

Our detector could dramatically change the manner and accuracy with which we are able to detect nuclear threats at home or abroad,” says Kar, associate professor in the Department of Physics. It could also help streamline radio-medicine, including radiation therapies and scanning diagnostics, boost the effectiveness of unmanned radiation monitoring vehicles in mapping and monitoring contaminated areas following disasters, and revolutionize radiometric imaging in space exploration. Made of graphene and carbon nanotubes, the researchers’ detector far outpaces any existing one in its ultrasensitivity to charged particles, minuscule size, low-power requirements, and low cost.

All radiation, of course, is not harmful, and even the type that may be depends on dosage and length of exposure. The word “radiation” refers simply to the emission and propagation of energy in the form of waves or particles. It has many sources, including the sun, electronic devices such as microwaves and cellphones, visible light, X-rays, gamma waves, cosmic waves, and nuclear fission, which is what produces power in nuclear reactors. Most of the harmful radiations are “ionizing radiations”—they have sufficient energy to remove electrons from the orbits of surrounding atoms, causing them to become charged, or “ionized.” It is those charged particles, or ions, that the detectors pick up and quantify, revealing the intensity of the radiation. Most current detectors, however, are not only bulky, power hungry, and expensive, they also cannot pick up very low levels of ions. Kar and Yung Joon’s detector, on the other hand, is so sensitive it can pick up just a single charged particle.

Our detectors are many orders of magnitude more sensitive in terms of how small a signal they can detect,” says Yung Joon, associate professor in the Department of Mechanical and Industrial Engineering. “Ours can detect one ion, the fundamental limit. If you can detect a single ion, then you can detect everything larger than that.”


Could Nanotechnology Kill Ebola?

The Ebola virus out­break in West Africa has claimed more than 1200 lives since Feb­ruary and has infected thou­sands more. Coun­tries such as Nigeria and Liberia have declared health emer­gen­cies, while the World Health Orga­ni­za­tion dis­cuss ways to battle the outbreak. There is no known vac­cine, treat­ment, or cure for Ebola, which is con­tracted through the bodily fluids of an infected person or animal. But that doesn’t mean there’s not hope. In fact, Chem­ical Engi­neering Chair Thomas Webster’s lab (NorthEastern University) is cur­rently working on one pos­sible solu­tion for fighting Ebola and other deadly viruses: nanotechnology.
It has been very hard to develop a vac­cine or treat­ment for Ebola or sim­ilar viruses because they mutate so quickly,” explained Web­ster, the editor-​​in-​​chief of the Inter­na­tional Journal of Nanomed­i­cine. “In nan­otech­nology we turned our atten­tion to devel­oping nanopar­ti­cles that could be attached chem­i­cally to the viruses and stop them from spreading.
One par­ticle that is showing great promise is gold. According to Web­ster, gold nanopar­ti­cles are cur­rently being used to treat cancer. Infrared waves, he explained, heat up the gold nanopar­ti­cles, which, in turn, attack and destroy every­thing from viruses to cancer cells, but not healthy cells.

Rec­og­nizing that a larger sur­face area would lead to a quicker heat-​​up time, Webster’s team cre­ated gold nanos­tars. “The star has a lot more sur­face area, so it can heat up much faster than a sphere can,” Web­ster said. “And that greater sur­face area allows it to attack more viruses once they absorb to the par­ti­cles.” In addi­tion to the gold nanos­tars, Webster’s lab is also gen­er­ating a nanopar­ticle that would serve as a “virus decoy,” chem­i­cally attracting the virus to attack it rather than healthy cells.


How To Kill Cancerous Cells Instantaneously

The first preclinical study of a new Rice University – developed anti-cancer technology found that a novel combination of existing clinical treatments can instantaneously detect and kill only cancer cells — often by blowing them apart — without harming surrounding normal organs. The work was conducted by researchers from Rice, the University of Texas MD Anderson Cancer Center and Northeastern University.

The first preclinical study of the anti-cancer technology “quadrapeutics” found it to be 17 times more efficient than conventional chemoradiation therapy against aggressive, drug-resistant head and neck tumors

We address aggressive cancers that cannot be efficiently and safely treated today,” said Rice scientist Dmitri Lapotko, the study’s lead investigator. “Surgeons often cannot fully remove tumors that are intertwined with important organs. Chemotherapy and radiation are commonly used to treat the residual portions of these tumors, but some tumors become resistant to chemoradiation. Quadrapeutics steps up when standard treatments fail. At the same time, quadrapeutics complements current approaches instead of replacing them.”

The research is available in the online journal Nature Medicine.

How To Keep Your Heart Healthy

Since the heart is such a del­i­cate and crit­ical organ, clin­i­cians usu­ally opt not to inter­vene with the dead cells that remain after a heart attack or car­diac dis­ease. “But we think that all heart attacks deserve some kind of treat­ment because it puts so much stress on the rest of the heart,” said Thomas Web­ster, pro­fessor and chair of the Depart­ment of Chem­ical Engi­neering at Northeastern University. “Even a square cen­timeter of dead heart tissue can put sig­nif­i­cant strain on the rest of the heart, which has to pick up the slack”, he said.

Webster’s ear­lier work demon­strated that adding nanofea­tures to an implanted med­ical device like a tita­nium knee or hip joint helps the car­ti­lage cells adhere to the device. This pro­motes tissue growth and allows the patient to heal more readily, he explained. While his team mem­bers don’t know exactly why this hap­pens, they have a good idea. They think the nanofea­tures allow the sur­face to more accu­rately mimic the nat­ural envi­ron­ment in the body, thus pro­viding more hab­it­able accom­mo­da­tions for the new cells.

But tita­nium hearts aren’t a viable option. Instead, they uti­lized a hydrogel, which they’d devel­oped pre­vi­ously, to mimic the heart cells them­selves. They added carbon nan­otubes to the hydrogel, making it con­duc­tive, and then injected the mate­rial into the heart, where it solid­i­fies at body tem­per­a­ture. Because the hydrogel is “super sticky,” it adheres extremely well to the tissue sur­face and imme­di­ately begins expanding and con­tracting in sync with the beating of the heart. While the team hasn’t yet tested the mate­rial in an animal model, it has sim­u­lated these con­di­tions in the lab.


Entire Genome Sequencing in Minutes?

The claim that nanopore technology is on the verge of making DNA analysis so fast and cheap that a person’s entire genome could be sequenced in just minutes and at a fraction of the cost of available commercial methods, has resulted in overwhelming academic, industrial, and global interest. But a review by Northeastern University – Boston – physicist Meni Wanunu, published in a special issue on nanopore sequencing in Physics of Life Reviews, questions whether the remaining technical hurdles can be overcome to create a workable, easily produced commercial device.

Earlier this year Oxford Nanopore Technologies, one of the pioneering companies of sequencing discoveries, announced that they expect nanopore strand sequencing to achieve a 15-minute genome by 2014 at a cost of $1,500. This is a far cry from the $10 million it cost to sequence an entire genome just 5 years ago. Since the idea of nanopore sequencing was first proposed in the mid 1990s, huge advances have been made. The basic idea is exceedingly simple: a single thread of DNA is passed through a tiny molecule-sized hole—or nanopore—and the various DNA bases are identified in sequence as they move through the pore.

But according to Wanunu, the reality of manipulating technology based on pores so tiny that 25,000 of them can fit side by side on a human hair has proved a daunting task. The main challenge has been to slow the process down and control the movement of the DNA strand through the pore at a rate slow enough to make individual DNA bases readable and usable. A new approach using enzyme-controlled movement, developed to overcome this problem, has its own drawbacks including poor enzyme activity resulting in limited processivity and uncontrolled forward-reverse motion.