Today's KNOWLEDGE Share : Brain Stimulation

 Today's KNOWLEDGE Share

Ultrasound offers a new way to perform deep brain stimulation

MIT engineers’ implantable ImPULS device could become an alternative to the electrodes now used to treat Parkinson’s and other diseases.

Deep brain stimulation, by implanted electrodes that deliver electrical pulses to the brain, is often used to treat Parkinson’s disease and other neurological disorders. However, the electrodes used for this treatment can eventually corrode and accumulate scar tissue, requiring them to be removed.

MIT researchers have now developed an alternative approach that uses ultrasound instead of electricity to perform deep brain stimulation, delivered by a fiber about the thickness of a human hair. In a study of mice, they showed that this stimulation can trigger neurons to release dopamine, in a part of the brain that is often targeted in patients with Parkinson’s disease.

“By using ultrasonography, we can create a new way of stimulating neurons to fire in the deep brain,” says Canan Dagdeviren, an associate professor in the MIT Media Lab and the senior author of the new study. “This device is thinner than a hair fiber, so there will be negligible tissue damage, and it is easy for us to navigate this device in the deep brain.

In addition to offering a potentially safer way to deliver deep brain stimulation, this approach could also become a valuable tool for researchers seeking to learn more about how the brain works.

MIT graduate student Jason Hou and MIT postdoc Md Osman Goni Nayeem are the lead authors of the paper, along with collaborators from MIT’s McGovern Institute for Brain Research, Boston University, and Caltech. The study appears today in Nature Communications.

Deep in the brain

Dagdeviren’s lab has previously developed wearable ultrasound devices that can be used to deliver drugs through the skin or perform diagnostic imaging on various organs. However, ultrasound cannot penetrate deeply into the brain from a device attached to the head or skull.

“If we want to go into the deep brain, then it cannot be just wearable or attachable anymore. It has to be implantable,” Dagdeviren says. “We carefully customize the device so that it will be minimally invasive and avoid major blood vessels in the deep brain.”

Deep brain stimulation with electrical impulses is FDA-approved to treat symptoms of Parkinson’s disease. This approach uses millimeter-thick electrodes to activate dopamine-producing cells in a brain region called the substantia nigra. However, once implanted in the brain, the devices eventually begin to corrode, and scar tissue that builds up surrounding the implant can interfere with the electrical impulses.

The MIT team set out to see if they could overcome some of those drawbacks by replacing electrical stimulation with ultrasound. Most neurons have ion channels that are responsive to mechanical stimulation, such as the vibrations from sound waves, so ultrasound can be used to elicit activity in those cells. However, existing technologies for delivering ultrasound to the brain through the skull can’t reach deep into the brain with high precision because the skull itself can interfere with the ultrasound waves and cause off-target stimulation.

“To precisely modulate neurons, we must go deeper, leading us to design a new kind of ultrasound-based implant that produces localized ultrasound fields,” Nayeem says. To safely reach those deep brain regions, the researchers designed a hair-thin fiber made from a flexible polymer. The tip of the fiber contains a drum-like ultrasound transducer with a vibrating membrane. When this membrane, which encapsulates a thin piezoelectric film, is driven by a small electrical voltage, it generates ultrasonic waves that can be detected by nearby cells.

“It’s tissue-safe, there’s no exposed electrode surface, and it’s very low-power, which bodes well for translation to patient use,” Hou says.

In tests in mice, the researchers showed that this ultrasound device, which they call ImPULS (Implantable Piezoelectric Ultrasound Stimulator), can provoke activity in neurons of the hippocampus. Then, they implanted the fibers into the dopamine-producing substantia nigra and showed that they could stimulate neurons in the dorsal striatum to produce dopamine.

“Brain stimulation has been one of the most effective, yet least understood, methods used to restore health to the brain. ImPULS gives us the ability to stimulate brain cells with exquisite spatial-temporal resolution and in a manner that doesn’t produce the kind of damage or inflammation as other methods. Seeing its effectiveness in areas like the hippocampus opened an entirely new way for us to deliver precise stimulation to targeted circuits in the brain,” says Steve Ramirez, an assistant professor of psychological and brain sciences at Boston University, and a faculty member at B.U.’s Center for Systems Neuroscience, who is also an author of the study.

A customizable device

All of the components of the device are biocompatible, including the piezoelectric layer, which is made of a novel ceramic called potassium sodium niobate, or KNN. The current version of the implant is powered by an external power source, but the researchers envision that future versions could be powered a small implantable battery and electronics unit.

The researchers developed a microfabrication process that enables them to easily alter the length and thickness of the fiber, as well as the frequency of the sound waves produced by the piezoelectric transducer. This could allow the devices to be customized for different brain regions.

“We cannot say that the device will give the same effect on every region in the brain, but we can easily and very confidently say that the technology is scalable, and not only for mice. We can also make it bigger for eventual use in humans,” Dagdeviren says.

The researchers now plan to investigate how ultrasound stimulation might affect different regions of the brain, and if the devices can remain functional when implanted for year-long timescales. They are also interested in the possibility of incorporating a microfluidic channel, which could allow the device to deliver drugs as well as ultrasound.

In addition to holding promise as a potential therapeutic for Parkinson’s or other diseases, this type of ultrasound device could also be a valuable tool to help researchers learn more about the brain, the researchers say.

“Our goal to provide this as a research tool for the neuroscience community, because we believe that we don’t have enough effective tools to understand the brain,” Dagdeviren says. “As device engineers, we are trying to provide new tools so that we can learn more about different regions of the brain.”

The research was funded by the MIT Media Lab Consortium and the Brain and Behavior Foundation Research (BBRF) NARSAD Young Investigator Award.

source:news.mit.edu

Covestro and Partners Launch Research Project to Recycle End-of-Life PU Mattress Foams

Material efficiency is the key objective when creating a new material cycle for flexible polyurethane (PU) foam from used mattresses. The French company Ecomaison has been working with Covestro for a few years to utilize its chemical recycling technology for this purpose. With this advanced process, both raw materials originally used can be recovered – the polyol as well as the precursor to the isocyanate TDI.

The aim of the partners is to recycle the sorted polyurethane foams as efficiently as possible. They will do this by combining mechanical and chemical technologies after careful sorting by foam type in the mattress cutting plants.

To Explore All Possibilities in A Future-oriented Foam Recycling Ecosystem:

Collaborations leveraging own expertise with like-minded partners are key. In addition to Ecomaison and Covestro, the French dismantling company Secondly and Federal Eco Foam, a Belgian specialist in the mechanical recycling of flexible foams, are involved as partners in the project. The project is planned to run for a maximum of 24 months. The project is called Foam Recycling Ecosystem Evolution (FREE) and coordinated by Covestro and half-funded by Ecomaison.

For the FREE consortium, the motivation lies in the added value of the material that can be recovered from the used foams and the opportunity to enter a more sustainable circular economy. The partners want to explore all possibilities in a future-oriented foam recycling ecosystem. They are convinced that chemical and mechanical recycling will complement each other in a meaningful way. As dismantler and sorting actor, Secondly is interested in empowering its sorting processes to be able to supply to recyclers a specified quality of foam.

At the same time, the project will provide a good picture of how the foam recycling market in the coming years may look like. The partners truly believe that chemical and mechanical recycling can be complementary given different specifications of inlet materials being sorted already at dismantlers. To provide added value to the PU foam material, the consortium will investigate all possibilities in a future oriented eco-system of foam recycling.

To Compare the Recycling Processes for Sorted Foams for Economic Feasibility

The research and development project includes the foam sorting at the dismantling step. It also includes a comparative feasibility study for two recycling processes for the sorted foams covering economic and ecologic value co-creation.

A few years ago, Covestro and its partners developed a chemical recycling process that is the only one of its kind capable of ultimately recovering both main raw materials of flexible PU foams in high purity.

source: Covestro/omnexus.specialchem.com

Today's KNOWLEDGE Share : Researchers Innovate Adhesive Smart Skin for Advanced Health Monitoring

Today's KNOWLEDGE Share

Skin can send certain health-related signals, such as dry skin feeling tighter to indicate the need for moisture. But what if skin could be smarter, capable of monitoring and sharing specific health information, such as the concentration of glucose in sweat or heart rate?

That was the question driving a team led by Penn State researchers that recently developed an adhesive sensing device that seamlessly attaches to human skin to detect and monitor the wearer’s health.

Multifunctional Adhesive Device Patch:

Co-corresponding author Huanyu “Larry” Cheng, the James L. Henderson, Jr. Memorial associate professor of engineering science and mechanics in the Penn State College of Engineering explained that conventional fabrication techniques for flexible electronics can be complicated and costly, especially as sensors built on flexible substrates, or foundational layers, are not necessarily flexible themselves.

“Despite significant efforts on wearable sensors for health monitoring, there haven’t been multifunctional skin-interfaced electronics with intrinsic adhesion on a single material platform prepared by low-cost, efficient fabrication methods. This work, however, introduces a skin-attachable, reprogrammable, multifunctional, adhesive device patch fabricated by simple and low-cost laser scribing,” said Cheng.

The sensor’s rigidity can limit the flexibility of the entire device. Cheng’s team previously developed biomarker sensors using laser-induced graphene (LIG), which involves using a laser to pattern 3D networks on a porous, flexible substrate. The interactions between the laser and the materials contained in the substrate produce conductive graphene.

“However, the LIG-based sensors and devices on flexible substrates are not intrinsically stretchable and can’t conform to interface with human skin for bio-sensing,” Cheng said, noting that human skin is changeable in shape, temperature and moisture levels, especially during physical exertion when monitoring heart rate, nerve performance or sweat glucose levels might be necessary. “Although LIG can be transferred to stretchable elastomers, the process can greatly reduce its quality.”

Innovative Solution with Adhesive Composite:

As a result, Cheng said, it’s more difficult to program a sensor device to monitor specific biological or electrophysical signals. Even when the device can be appropriately programmed, its sensing performance is often degraded.

“To address these challenges, it is highly desirable to prepare porous 3D LIG directly on the stretchable substrate,” said co-author Jia Zhu, who graduated with a doctorate in engineering science and mechanics from Penn State in 2020 and is now an associate professor at the University of Electronic Science and Technology of China.

The researchers achieved this goal by making an adhesive composite with molecules called polyimide powders that add strength and heat resistance and amine-based ethoxylated polyethylenimine — a type of polymer that can modify conductive materials — dispersed in a silicone elastomer, or rubber. The stretchable composite not only accommodates direct 3D LIG preparation, but also its adhesive nature means it can conform and stick to non-uniform, changeable shapes — like humans.

The researchers experimentally confirmed that the device can monitor the pH value, glucose and lactate concentrations in sweat as well as can be detected via finger prick blood draws. It can also be reprogrammed to monitor heart rate, nerve performance and sweat glucose concentrations in real time.

Reprogramming is as simple as applying clear tape over the LIG networks and peeling them off. The substrate can then be re-lasered to new specifications, up to four times before it becomes too thin. Once it becomes too thin, the entire device can be recycled.

Future Potential and Applications:

Critically, according to Cheng, the device remains adhesive and capable of monitoring even when the skin is made slick with sweat or water. Currently powered by batteries or near-field communication nodules, like a wireless charger, the device could potentially harvest energy and communicate over radio frequencies, which researchers said would result in a standalone, stretchable adhesive platform capable of sensing desired biomarkers and monitoring electrophysical signals.

The team said they plan to work toward this goal, in collaboration with physicians, to eventually apply the platform to manage various diseases such as diabetes and monitor acute issues like infections or wounds.

“We would like to create the next generation of smart skin with integrated sensors for health monitoring — along with evaluating how various treatments impact health — and drug delivery modules for in-time treatment,” Cheng said.

Cheng is also affiliated with the departments of biomedical engineering, of mechanical engineering, of architectural engineering and of industrial and manufacturing engineering, as well as the materials research institute and the institute for computational and data sciences.

Other collaborators affiliated with the Department of Engineering Science and Mechanics at Penn State include Xianzhe Zhang, Chenghao Xing and Shangbin Liu, all graduate students; and Farnaz Lorestani, associate research fellow. Co-authors from outside of Penn State include Yang Xiao, Jiaying Li, Ke Meng, Min Gao, Taisong Pan and Yuan Lin, all with the University of Electronic Science and Technology of China; and Yao Tong, Yingying Zhang, Senhao Zhang, Benkun Bao and Hongbo Yang with the Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences. Li is also affiliated with the institute.

The U.S. National Institutes of Health, the U.S. National Science Foundation, Penn State, the University of Electronics Science and Technology China and the National Natural Science Foundation of China funded this research.

Source: Pennsylvania State University/adhesives.specialchem.com

SABIC to Highlight First Commercial Application of its High-heat Dielectric Film:

SABIC will highlight at PCIM Europe 2024 (in Hall 7, Booth 140) the first commercial application of its high-heat ELCRES™ HTV150A dielectric film.

Japan’s Nichicon Corporation used this ultra-thin specialty film to develop high-temperature, high-voltage, commercial-quality capacitors for AC-DC traction inverter modules in electric vehicles. This technological breakthrough addresses industry demand for advanced film capacitors which can enable more-efficient AC-DC power modules.

Can Operate at High Temperatures and High Voltages:

In contrast to traditional film solutions, single capacitors made with ELCRES™ HTV150A dielectric films can operate at high temperatures (up to 150°C) and high voltages (up to 1,000 volts) with stable performance. Working with SABIC, Nichicon implemented and successfully tested the film in its capacitor designs to offer candidate components to AC-DC inverter module manufacturers. A prototype capacitor will be shown at the SABIC booth.

“Our new capacitors made with SABIC’s dielectric film can help the industry realize the full benefits of silicon carbide and gallium nitride MOSFETs when used in AC-DC inverters for electric vehicles. We are pleased to collaborate with SABIC to combine our engineering leadership with SABIC’s renowned materials innovation.” 

Segmented Metallization to Achieve High Voltages:

The development project for Nichicon’s film capacitors involved the segmented metallization of the ELCRES™ HTV150A film to help achieve 900-1000V. The film’s stable, inherent dielectric properties enable the capacitors to operate at 150°C. This work included 2,000 hours of reliability life testing at 150°C, and 3,600 hours at 130°C.

“We engineered ELCRES™ HTV150A films to help customers move to the latest generation of capacitor technology, and we congratulate Nichicon on taking the lead in this endeavor,” said Scott Fisher, general manager, Technology, SABIC Polymers, Specialties BU. “Nichicon’s new film capacitors offer the potential to improve electric vehicle range, charging speed and performance, and to allow compact, lighter-weight module designs by reducing the need for active cooling.

Addresses Critical Performance Gap in Traditional Film Solutions Above 105°C

ELCRES™ HTV150A dielectric films are the first in the industry to provide stable performance at operating temperatures of -40°C to 150°C and frequencies up to 100 kHz, while offering stable capacitance, high insulation resistance and good dielectric performance.

The films address the critical performance gap experienced by traditional film solutions above 105°C. Capacitors built with 3 µm and 5 µm metalized ELCRES™ HTV150A films pass standard electrical and life tests at 150°C for 2,000 hours, and damp heat aging at 85°C and 85 percent relative humidity for 1,000 hours, with low capacitance change and stable insulation resistance.

Source: SABIC/omnexus.specialchem.com

Today's KNOWLEDGE Share:The reason for Shrinkage

Today's KNOWLEDGE Share

The oriented skin will shrink only 0.1 or 0.2 %, where the transverse core will want to shrink possibly 1%.

The conflict results in a compressive stress in the skin, due to the action of the core, trying to shrink so much more than the skin. Easy, right ?

So the skin is in a fairly safe state of COMPRESSION (failure comes with tension).

Sure ?

Zooming inside the skin, we must realize that the very reason for the shrinkage to be so small in the fiber direction, is because the much higher shrinkage of the polymer is constrained by the glass fibers. So the polymer in between the fibers is desperately trying to shrink 2%, but the glass will keep the polymer under....TENSION !

So the skin is in compression yes, but the polymer, in the skin, is in tension !

source:Vito leo

Today's KNOWLEDGE Share : Cost Effective Flame-retardant Synergist

Today's KNOWLEDGE Share

CAI Performance Additives announces the launch of ST-FR322™ flame retardant synergist.

ST-FR322™ is an environmentally friendly alternative that delivers exceptional performance and cost savings for a wide range of plastic applications.

Offering Safe Alternative to FRs Containing Antimony Trioxide:

ST-FR322™ is a unique organic and inorganic complex substance, free from harmful heavy metals. This innovative additive offers a compelling alternative to traditional flame retardants containing antimony trioxide, which raise environmental and health concerns.

The product shows a powerful synergistic effect when combined with halogenated flame retardants. It effectively replaces antimony trioxide in equal amounts in various plastics, including PA, PBT, ABS, HIPS, PS, PVC, PP, PE, EVA, and more.

Remarkably, ST-FR322™ achieves the same level of flame retardancy as antimony trioxide while offering several additional benefits:

Reduced smoke production

Anti-dripping effect

Cost savings

Improved processing

Excellent thermal stability

ST-FR322™ delivers superior performance, environmental responsibility, and cost-effectiveness, making it an ideal choice for a variety of plastic applications.

Company’s commitment to provide innovative solutions for the plastics industry, and the introduction of ST-FR322™ is just one example of their dedication to delivering superior products that meet the evolving needs of our customers. ST-FR322™ is available now in commercial quantities.

Source: CAI Performance Additives/polymer-additives.specialchem.com

SABIC Highlights its Diverse Portfolio of Polyetherimide Resins at AIX 2024

ULTEM™ resin, a polyetherimide (PEI), is adaptable to a wide range of formats, including foam, sheet, fiber, powder, and composite and honeycomb structures. Due to their versatility and desirable attributes, these resins offer the industry a smooth transition path from traditional thermosets to lighter, more environmentally cautious and more easily processed thermoplastics.

Displaying Aircraft Applications of ULTEM™ Resin:

At its exhibit (Stand #6C51B), the company is displaying aircraft applications that benefit from a variety of ULTEM™ materials. These include interior parts, seating, lighting, structural elements, electrical components and composites.

To address the industry’s sustainability goals, SABIC is showing how these different ULTEM™ material formats support mono-material designs that may simplify recycling. Furthermore, SABIC supplies ULTEM™ resin grades containing certified International Sustainability and Carbon Certification Plus (ISCC+) renewable feedstock.

“With our long history of providing high-performance ULTEM™ materials to the aerospace industry, and strong focus on sustainable solutions, SABIC is perfectly positioned to address current and emerging aerospace challenges,” said Maureen MacDonald-Stein, director, Portfolio Strategy and Marketing, SABIC Polymers, Specialties business, SABIC. “We are helping customers replace traditional materials with thermoplastics to cut weight, streamline processing and reduce carbon footprint. To facilitate this transition, SABIC offers a variety of ULTEM™ materials that can enhance design flexibility, meet application and regulatory requirements, and may help drive down system costs. Our exhibit at AIX 2024 showcases the breadth and depth of our portfolio of high-heat materials.” 

ISCC+ Certified Renewable Grades

The wide array of ULTEM™ formats on display at AIX 2024 can empower designers to adopt mono-material applications that facilitate recycling. Combining injection molded components with foam, sheet, composites or textiles – all made with ULTEM™ materials – can help avoid the need for costly separation at end of life. Mono-material designs made with ULTEM™ grades can also help to streamline the supply chain vs. sourcing disparate materials from multiple suppliers. 

Also contributing to sustainability are the ISCC+ certified renewable ULTEM™ grades that deliver the same high performance and processability as incumbent materials, enabling them to serve as drop-in alternatives, and potentially shortening their qualification cycle. Certified renewable ULTEM™ resins can potentially reduce carbon footprint by up to 10 percent compared to fossil-based incumbent grades.

An example is a cove lighting concept made with ISCC+ certified renewable ULTEM™ 9085 resin. It is developed by Vaupell, a tier supplier to the aerospace industry, which will be on display at SABIC’s booth. 

For Extremely Lightweight and Strong Honeycomb Structures

ULTEM™ resin can be used in a variety of formats to meet the needs of aircraft interior applications. In injection-molded parts such as passenger service unit, ULTEM™ 9085 resin with molded-in color can enhance aesthetics, cut weight and ensure dimensional stability. ULTEM™ 1010 resin can be used to extrude exceptionally lightweight and strong honeycomb structures for interior parts such as side walls, ceilings and galley builds. Other structural applications featured at the SABIC booth include brackets and fasteners. 

For electrical and fiber optic connectors, ULTEM™ 2300 resin and EXTEM™ XH2115 resin deliver a low coefficient of thermal expansion (CTE) and excellent dimensional stability. They also enable thin-wall, complex connector designs. 

SILTEM™ resins combine the high-heat performance of ULTEM™ resin with the flexibility of silicone elastomers. These deliver high performance in extruded wire & cable applications without intentionally added per-and polyfluoroalkyl substances (PFAS).

Powder Alternative to PEEK

ULTEM™ CRS powder can be used in carbon fiber composites and unidirectional (UD) tapes for structural parts as a potential alternative to polyetheretherketone (PEEK). 

Non-woven fleece and non-woven textiles are two key applications for ULTEM™ 9011 fiber. This fiber offers low flame/smoke/toxicity and resistance to UV light, heat and chemicals. Applications include lightweight panels and sandwich structures. 

ULTEM™ resins can be foamed to create lightweight cores or extruded into sheet products. They can also be metallized using electroless plating. At AIX 2024, SABIC is highlighting its collaboration with Cybershield, a U.S. supplier of metalized plastic components. The two companies are evaluating the plating compatibility, quality and performance of filled and unfilled ULTEM™ resins. 

While the ULTEM™ material portfolio is highly diversified, these amorphous thermoplastics share common attributes including compliance with FAR 25 853 regulations. They feature elevated thermal resistance, high strength and stiffness, broad chemical resistance, and inherent flame retardance. ULTEM™ materials can be extruded, thermoformed, extrusion blow molded, foamed and injection molded, and can be reinforced with glass or carbon fiber.

AIX 2024 is being held May 28-30, in Hamburg, Germany.

Source: SABIC/omnexus.specialchem.com