Nanogels For Heart Attack Patients

Heart disease and heart-related illnesses are a leading cause of death around the world, but treatment options are limited. Now, one group reports in ACS Nano that encapsulating stem cells in a nanogel could help repair damage to the heart.

Myocardial infarction, also known as a heart attack, causes damage to the muscular walls of the heart. Scientists have tried different methods to repair this damage. For example, one method involves directly implanting stem cells in the heart wall, but the cells often don’t take hold, and sometimes they trigger an immune reaction. Another treatment option being explored is injectable hydrogels, substances that are composed of water and a polymer. Naturally occurring polymers such as keratin and collagen have been used but they are expensive, and their composition can vary between batches. So Ke Cheng, Hu Zhang, Jinying Zhang and colleagues wanted to see whether placing stem cells in inexpensive hydrogels with designed tiny pores that are made in the laboratory would work.

The team encapsulated stem cells in nanogels, which are initially liquid but then turn into a soft gel when at body temperature. The nanogel didn’t adversely affect stem cell growth or function, and the encased stem cells didn’t trigger a rejection response. When these enveloped cells were injected into mouse and pig hearts, the researchers observed increased cell retention and regeneration compared to directly injecting just the stem cells. In addition, the heart walls were strengthened. Finally, the group successfully tested the encapsulated stem cells in mouse and pig models of myocardial infarction.


How To Keep Warm In Extreme Cold Weather

Some of the winter weather gear worn by the US Army was designed 30 years ago. It’s heavy and can cause overheating during exertion, while also not doing a very good job of keeping the extremities from going numb.


That’s problematic if soldiers have to operate weapons as soon as they land,” said Paola D’Angelo, a research bioengineer at the US Army’s Natick Soldier Research, Development and Engineering Center in Massachusetts. “So we want to pursue this fundamental research to see if we can modify hand wear for that extreme cold weather.”

Scientists are developing smart fabrics that heat up when powered and can capture sweat. The work, which was presented at the 254th National Meeting and Exposition of the American Chemical Society, is based on research from Stanford University in California. A team embedded a network of very fine silver nanowires in cotton, and was able to heat the fabric by applying power to the wires. D’Angelo and her colleagues are working to extend the approach to other fabrics more suitable for military uniforms, including polyester and a cotton/nylon blend. By applying three volts – the output of a typical watch battery – to a one-inch square of fabric, they were able to raise its temperature by almost 40 degrees C. The researchers are also incorporating a layer of hydrogel particles made of polyethylene glycol that will absorb sweat and stop the other layers of the fabric from getting wet.

Once we have optimised the coating, we can start looking at scaling up,” said D’Angelo. The fabric has been tested with up to three washes and still works the same as unwashed fabric for most of the textiles being tested.


Remote-Controlled NanoRobots Move Like A Bacterium In The Body

For the past few years, scientists around the world have been studying ways to use miniature robots to better treat a variety of diseases. The robots are designed to enter the human body, where they can deliver drugs at specific locations or perform precise operations like clearing clogged-up arteries. By replacing invasive, often complicated surgery, they could optimize medicine.

medical robots

Scientist Selman Sakar from Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland  teamed up with Hen-Wei Huang and Bradley Nelson at ETHZ to develop a simple and versatile method for building such bio-inspired robots and equipping them with advanced features. They also created a platform for testing several robot designs and studying different modes of locomotion. Their work, published in Nature Communications, produced complex reconfigurable microrobots that can be manufactured with high throughput. They built an integrated manipulation platform that can remotely control the robots’ mobility with electromagnetic fields, and cause them to shape-shift using heat.

Unlike conventional robots, these microrobots are soft, flexible, and motor-less. They are made of a biocompatible hydrogel and magnetic nanoparticles. These nanoparticles have two functions. They give the microrobots their shape during the manufacturing process, and make them move and swim when an electromagnetic field is applied.

Building one of these nanorobots involves several steps. First, the nanoparticles are placed inside layers of a biocompatible hydrogel. Then an electromagnetic field is applied to orientate the nanoparticles at different parts of the robot, followed by a polymerization step to “solidify” the hydrogel. After this, the robot is placed in water where it folds in specific ways depending on the orientation of the nanoparticles inside the gel, to form the final overall 3D architecture of the nanorobot.

Once the final shape is achieved, an electromagnetic field is used to make the robot swim. Then, when heated, the robot changes shape and “unfolds”. This fabrication approach allowed the researchers to build microrobots that mimic the bacterium that causes African trypanosomiasis, otherwise known as sleeping sickness. This particular bacterium uses a flagellum for propulsion, but hides it away once inside a person’s bloodstream as a survival mechanism.

The researchers tested different microrobot designs to come up with one that imitates this behavior. The prototype robot presented in this work has a bacterium-like flagellum that enables it to swim. When heated with a laser, the flagellum wraps around the robot’s body and is “hidden”.


Super Smart Band-Aids

This is what a band-aid in the future might look like. It’s a stretchable hydrogel that in many ways mimics
the properties of human tissue.

smart band-aid

Hydrogel is a polymer network infiltrated with water. Even though it is only 5 to 10 percent polymer, this network is extremely important“, says Xuanhe Zhao, Professor of Mechanical engineering at the Massachusetts Institute of Technology (MIT).

Important because the polymer makes up a microscopic scaffold that endows it with special properties uncommon to synthetic hydrogels. It is highly stretchable and can adhere easily to surfaces. Most importantly, it is specifically designed to be compatible with the human body – both inside and out. That compatibility could potentially give rise to a new class of biomedical devices.

We further embed electronic devices such as sensors, such as different drug delivery devices into this matrix to achieve what we call the smart applications“, comments Zhao.  Applications that could turn an ordinary band-aid into a tool to actively monitor and heal wounds autonomously. Zhao uses burns as an example… “Once the sensor senses an abnormal increase in temperature for example It will send out a command. Then the controlled drug delivery system can deliver a specific drug to that specific location“, he adds. The researchers are now fine tuning the properties and functionality of their hydrogels. They hope that soon healing everything from a scratch to an ulcer will be as simpleas putting on a band-aid.


Very High Density Energy Lithium-Ion Battery

Stanford University scientists have dramatically improved the performance of lithium-ion batteries by creating novel electrodes made of silicon and conducting polymer hydrogel, a spongy substance similar to the material used in soft contact lenses and other household products. The researchers have designed a new technique for producing low-cost, silicon-based batteries with potential applications for a wide range of electrical devices.

打印An illustration of a new battery electrode made from a composite of hydrogel and silicon nanoparticles (Si NP). Each Si NP is encapsulated in a conductive polymer surface coating and connected to a three-dimensional hydrogel framework

Developing rechargeable lithium-ion batteries with high energy density and long cycle life is of critical importance to address the ever-increasing energy storage needs for portable electronics, electric vehicles and other technologies,” said study co-author Zhenan Bao, professor of chemical engineering at Stanford.
The research has been published in the journal Nature Communications.


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.