Material that bends like micro-hair
12/30/14 There was a very interesting article in MIT News involving “micro” that we wanted to share with you. It is about a new material that bends like hair.
Article: MIT engineers have fabricated a new elastic material coated with microscopic, hairlike structures that tilt in response to a magnetic field. Depending on the field’s orientation, the microhairs can tilt to form a path through which fluid can flow; the material can even direct water upward, against gravity.
Each microhair, made of nickel, is about 70 microns high and 25 microns wide — about one-fourth the diameter of a human hair. The researchers fabricated an array of the microhairs onto an elastic, transparent layer of silicone. In experiments, the magnetically activated material directed not just the flow of fluid, but also light — much as window blinds tilt to filter the sun. Researchers say the work could lead to waterproofing and anti-glare applications, such as “smart windows” for buildings and cars. “You could coat this on your car windshield to manipulate rain or sunlight,” says Yangying Zhu, a graduate student in MIT’s Department of Mechanical Engineering. “So you could filter how much solar radiation you want coming in, and also shed raindrops. This is an opportunity for the future.” In the near term, the material could also be embedded in lab-on-a-chip devices to magnetically direct the flow of cells and other biological material through a diagnostic chip’s microchannels. Zhu reports the details of the material this month in the journal Advanced Materials. The paper’s co-authors are Evelyn Wang, an associate professor of mechanical engineering, former graduate student Rong Xiao, and postdoc Dion Antao.
The inspiration for the microhair array comes partly from nature, Zhu says. For example, human nasal passages are lined with cilia — small 
hairs that sway back and forth to remove dust and other foreign particles. Zhu sought to engineer a dynamic, responsive material that mimics the motion of cilia. “We see these dynamic structures a lot in nature,” Zhu says. “So we thought, ‘What if we could engineer microstructures, and make them dynamic?’ This would expand the functionality of surfaces.”
Zhu chose to work with materials that move in response to a magnetic field. Others have designed such magnetically actuated materials by infusing polymers with magnetic particles. However, Wang says it’s difficult to control the distribution — and therefore the movement — of particles through a polymer. Instead, she and Zhu chose to manufacture an array of microscopic pillars that uniformly tilt in response to a magnetic field. To do so, they first created molds, which they electroplated with nickel. They then stripped the molds away, and bonded the nickel pillars to a soft, transparent layer of silicone. The researchers exposed the material to an external magnetic field, placing it between two large magnets, and found they were able to control the angle and direction of the pillars, which tilted toward the angle of the magnetic field. “We can apply the field in any direction, and the pillars will follow the field, in real time,” Zhu says.
In experiments, the team piped a water solution through a syringe and onto the microhair array. Under a magnetic field, the liquid only flowed in the direction in which the pillars tilted, while being highly “pinned,” or fixed, in all other directions — an effect that was even seen when the researchers stood the array against a wall: Through a combination of surface tension and tilting pillars, water climbed up the array, following the direction of the pillars. Since the material’s underlying silicone layer is transparent, the group also explored the array’s effect on light. Zhu shone a laser through the material while tilting the pillars at various angles, and found she could control how much light passed through, based on the angle at which the pillars bent. In principle, she says, more complex magnetic fields could be designed to create intricate tilting patterns throughout an array. Such patterns may be useful in directing cells through a microchip’s channels, or wicking moisture from a windshield. Since the material is flexible, Wang says that it may even be woven into fabric to create rain-resistant clothing. “A nice thing about this substrate is that you can attach it to something with interesting contours,” Wang says. “Or, depending on how you design the magnetic field, you could get the pillars to close in like a flower. You could do a lot of things with the same platform.”
This research was supported by funding from the Air Force Office of Scientific Research.
Implantable Neuromodulation Devices Used To Fight Disease
12/22/14 Fascinating article recently released by DARPA regarding neuromodulation. Their release is below:
Many chronic inflammatory diseases and mental health conditions affecting military Service members and veterans involve abnormal activity in the peripheral nervous system, which plays a key role in organ function. Monitoring and targeted regulation of peripheral nerve signals offer great promise to help patients restore and maintain their health without surgery or drugs. Current neuromodulation devices are typically used as a last resort, however, because they are relatively large (about the size of a deck of cards), require invasive surgical implantation and often produce side effects due to their lack of precision. DARPA’s Electrical Prescriptions (ElectRx) program is seeking innovative research proposals to help transform neuromodulation therapies from last resort to first choice for a wide range of diseases.
ElectRx (pronounced “electrics”) aims to develop groundbreaking technologies that would use the body’s innate neurophysiology to restore and maintain health. In support of the White House’s brain initiative, ElectRx also seeks to accelerate understanding of specific neural circuits and their role in health and disease. Future therapies based on targeted peripheral neural stimulation could promote self-healing, reduce dependence on traditional drugs and provide new treatment options for illnesses.
ElectRx would leverage advanced sensing and stimulating technologies to target specific peripheral neural circuits that control organ functions. These feedback-controlled neuromodulation technologies would monitor health status and intervene as needed to deliver patient-specific therapeutic patterns of stimulation designed to restore a healthy physiological state. The program seeks to create ultraminiaturized devices that would require only minimally invasive insertion procedures such as injectable delivery through a needle.
“Many chronic illnesses occur when the body’s natural neuroelectrical and biochemical rhythms are disrupted, like playing wrong notes in music,” said Doug Weber, DARPA program manager. “ElectRx seeks to understand what the ‘right notes’ are for each person and provide real-time treatment to help the patient achieve and enjoy a harmonious, healthy baseline. Peripheral neuromodulation therapies based on ElectRx research could help maximize the immunological, physical and mental health of military Service members and veterans.”
The scope of ElectRx’ research is peripheral neuromodulation treatments for inflammatory diseases (which include rheumatoid arthritis, systemic inflammatory response syndrome and inflammatory bowel disease) and mental health disorders (such as post-traumatic stress disorder (PTSD), anxiety and depression). DARPA expects ElectRx proposers to identify a disease of interest to study and treat. The agency intends to determine overall program success based on advancement of minimally or non-invasive interface technology, the capability to target specific nerves without side effects, validation of biological input/output pathways, and potential for translating this knowledge into an integrated, closed-loop neural-visceral interface for monitoring and maintaining health.
The DARPA Special Notice document describing the specific capabilities sought is available at http://go.usa.gov/6zpW. The Broad Agency Announcement with full technical details on ElectRx is available at http://go.usa.gov/F88T. For more information, please email DARPA-BAA-15-06@darpa.mil.
ElectRx plans to explore two principal technical areas:
Technical Area 1 (TA1): Systems approaches to neurobiological discovery and closed-loop control of physiological status in vivo. Proposals should aim to elucidate the neurobiological foundations of the proposed disease target and use the new insights derived from the physiological studies to drive closed-loop neuromodulation system design and implementation. These efforts should culminate with in vivo demonstrations of predictable and automatic restoration of healthy physiological states in response to on-board physiological state monitoring.
Technical Area 2 (TA2): Advanced component technology development. Proposals to TA2 should develop and demonstrate in vivo advanced minimally and non-invasive (atraumatic) component technologies, including novel sensing modalities and neural interface technologies. Depending on research results, DARPA may integrate effective technologies developed in both technical areas in a future add-on research phase.
Micro molding with Micro Engineering Solutions
12/16/14 Micro molding refers to a set of fabrication techniques that produce tiny speck-sized components or extremely small features on larger plastic products. As technology has advanced, it is now possible to use equipment customized to micro molding rather than attempting to scale down part size on standard molding machines. MES is expert in the art of micro molding, and allows its clients to take advantage of the inherent advantages of the process which include relatively inexpensive tooling, quick cycle times, extremely accurate parts, achievement of tight tolerances, and the attainment of seemingly radical part geometries.
Powder Inhaler Micro Component
The key to achieving success in micro molding is to choose your supplier carefully, as an in-depth understanding of the vagaries of the process and expertise in the execution of mission critical projects is vital. The nature of micro molding is such that it cannot simply be treated as a scaled down version of traditional molding, as numerous tolerances and behaviors of parts and materials change hugely when working at the micron level. More and more OEMs are treating their micro manufacturing sub-contractors as project partners these days, as the key to success in micro manufacturing in general and micro molding in particular is an appreciation of the nuts and bolts of the process from the very early stages of product design.
MES works with clients who have a rough conception of product characteristics or fully worked up 3D CAD solid models all the way through design, assembly, and high volume manufacturing of micro molded components. What is important is an ability to assess the manufacturability of products early in the design stage, and to be able to advise clients of design reiterations that may be necessary to save the cost of manufacturing problems found post-tooling.
MATERIAL ADVANCES THAT EFFECT THE MICRO MEDICAL DEVICE FIELD
12/10/14 QMed published an article recently listing 6 important material advances in the micro medical device field that are changing how we do things today. 
1. Synthetic Collagen Fibers – Researchers at Rice University have been working on better understanding collagen fibers and how they can self-assemble with their sticky ends.
The study explains how mimetic peptides developed at the university may align to form helices with sticky ends that will allow them to aggregate into fibers or gels.
Once arranged in the correct order, the charged amino acids cross-link into non-covalent bonds that hold the helices together with stabilizing hydrogen bonds.
This could pave the way to better synthetic collagen for tissue engineering to be used in cosmetic and reconstructive medicine.
2. Biodegradable Orthopedic Materials – German researchers are using powder injection molding to manufacture a suture anchor made of degradable metal ceramic composites. Their research used a metal component based on iron alloy combined with beta-tricalcium phosphate as the ceramic component. They have concluded that the iron alloys corrode slowly and ensure higher mechanical strength while the ceramic decomposes quickly and simulated bone growth while aiding he ingrowth of the implant. This means biodegradable implants that can be completely absorbed by the body, getting rid of the need for additional surgery to remove the implant. Many avenues are currently being explored in the biodegradable implant field. The key difference in this german study is the powder injection molding process. This process allows:
a. the production of complex structures cost effectively and in high quantities
b. properties like density and porosity to be controlled selectively – a crucial aspect when developing materials with high mechanical strengths.
This type of research could revolutionize the way surgical procedures are done in the future as well as serve as a building block for other biodegradable implants.
3. Open-cell Silicones – In the search for new medical device materials, the choice is between open- and closed-cell structures. A common open-cell material being polyurethane, is primarily used in non-implantable products like cleaning devices and absorbent pads. The commonly used closed-cell material is silicone, which is biocompatible but unsuitable for implantation. And todays open-cell silicones are not fully open-cell structures. This could all change… a company in California has developed a manufacturing process that produces fully open-celled silicones suitable for a variety of implantable short term & long term medical device applications. They can also play a role in tissue scaffolding, tissue integration and cell seeding.
4. Blood Clot and Bacteria Resistant Coating Material – Harvard University has created a surface coating for medical devices that repels blood and bacteria which helps the body ward off infection and avoid harmful blood clotting. The genesis of the material for the coating evolved from a pioneering surface technology – SLIPS (Slippery Liquid-Infused Porous Surfaces). SLIPS is designed to repel almost any material it contacts.
5. Shape Memory Polymers – Shape shifting thiolene/acrylates could open the door to a host of applications in medical technology. Researchers at UT Dallas used previous 3M technology on thiol-type polymers because of its ability to soften and change shape under human body temperatures. It could be used as implantable nerve tags that could read electrical signals in an arm stump to power robotic prosthetics. It has great adhesion with metals which makes it a highly useful flexible electrical material.
6. Tough Degradable Material – One limitation of many resorbable biomaterials is their strength. They are very strong at first, then their strength degrades quickly. A Swedish company “knitted” together two degradable polymers to create a surgical mesh that provides tissue support for 6-9 months. The first polymer, TMC, was engineered for fast resorption, giving strength for 2 months. The second, a copolymer of lactide and TMC, maintains strength for 6-9 months, then completely degrades within 3 years. The quick dissolving fiber offers the initial strength once implanted to keep the tissues tight. Once this fiber dissolves, the second is a more elastic mesh. This variable strength and elasticity profile assists the body in healing itself. This fiber is currently being used in hernia reconstruction and breast surgery.
With this wave of new material technology, the way we use medical devices will change greatly and aid in the healing process of the body.
SWALLOWABLE DISSOLVABLE MICRO DEVICES
12/3/14 A few Hollywood blockbusters over the years (and quite a few more that could be termed “non-Blockbusters”) have been fascinated by the idea of miniaturizing the lead actors so that they operate in a super-sized world. I guess we all remember Dennis Quaid, captain of the mini-submarine injected into an unsuspecting host in the 1980s film Innerspace, and the adventures that ensued!
OK, so the laws of physics (if not common sense) relegate such notions to fiction. But go back to 1966 when the film Fantastic Voyage (upon which Innerspace was based) was released, and some of the advances in medical science that we have seen over the ensuing 50 years would seem just as fanciful as reducing a submarine to the size of a grain of sand.
Today, we talk about the possibility of swallowing medical devices that are able to target specific areas of the body, perform their therapeutic miracles, and then dissolve and disappear, as if they are everyday elements of our lives. The impossible of yesterday is overcome day by day in this modern technologically advanced world.
While I will not now map out how long it will be before Dennis Quaid will be able to navigate his Ohio-Class sub through your body, I would like to look at what is possible today in the medical sector due to massive recent advances in micro manufacturing and material developments.
Here at MES, we are privileged to work with an array of companies that are pioneering new medical treatments and diagnostic equipment. For the medical sector, miniaturization is key, and the drive is always to move towards minimally invasive treatments and diagnostics. The knock on effect in terms of quicker patient recovery and reduced strain on national health budgets make this an objective that will never go away. Medical device OEMs also know the bottom line advantages that exist if they are able to market miniature, efficient, and innovative products in a timely fashion, hence the number of them that work with MES to tap into our micro medical expertise.
The key to unlocking the potential for dissolving medical devices is recent advances in a new class of biocompatible bio-resorbable polymers. Bio-resorbable polymers, also referred to as degradable polymers, are polymer materials that can be safely absorbed by the body so that the materials from which a construction is made disappear over time.
The most common bio-resorbable polymer is polylactic acid (PLA), also known as polylactide, which is made from a lactide monomer. Generally speaking, PLA is the main building block for bio-resorbable polymer materials. Common derivatives of PLA are poly-L-lactide (PLLA), poly-D-lactide (PDLA) and poly-DL-lactide (PDLLA). When in the body, PLA degrades into lactic acid, a non-toxic chemical which occurs naturally in the body.
Polyglycolic acid (PGA), or polyglycolide (PG), is another type of bio-resorbable polymer usually used for bio-resorbable sutures. The material can be copolymerized with lactic acid to form poly(lactic-co-glycolic acid) or PLGA, with e-caprolactone to form poly(glycolide-co-caprolactone) or PGCL, and with trimethylene carbonate to form poly(glycolide-co-trimethylene carbonate) or PGA-co-TMC. PGA degrades to form glycolic acid.
There are extremely important steps required when handling, testing, processing, and validating bio-resorbable molded components. Material characterization throughout the molding process is critical to understand what happens to the Intrinsic Viscosity of bio-resorbable polymers such that when they are in the body, they will not prematurely resorb, or alternatively, stay too long for the implant to properly function.
As is usually the case in micro molding, this type of processing requires specialized equipment, design, and validation expertise, so working with the likes of MES which is experienced in bio-resorbable processing and micro feature generation can create a faster and more cost-effective path to success.
Use of bio-resorbable materials allow for the manufacture of some truly innovative products that can be implanted in the body. We have recently, for example, seen the arrival of dissolvable stents that disappear after two years in situ, a huge step forward in the treatment of heart disease globally.
Countless other implantable bio-resorbable devices exist today, and more appear all the time. But what happens when you are able to include power in your implantable devices. Now the possibilities become endless and the very real possibility of complex functioning dissolvable devices begins to loom.
Welcome to the weird and wonderful world of bio-degradable batteries and dissolvable electronics, the foundation stones of fully functioning powered medical devices that can be swallowed and which dissolve over time. In one recently announced development, engineers have made a wireless microchip made of silicon, magnesium, and reconstituted silk. Once its work is done, it dissolves, triggered initially by the silk and how it is woven into the other elements, and is flushed out of the body.
As a facilitating technology, this dissolvable microchip could power a tiny device that would fight infections after surgery and then dissolve when its mission is accomplished. How about a small imaging device that takes pictures in the body, sends the images remotely to a computer, and then dissolves. Such advances would be hugely beneficial, eliminating the need to resort to surgical intervention to remove devices.
In another application, ingestible smart pills containing tiny batteries, sensors, and transmitters to monitor a range of health data and wirelessly share this information with a medical practitioner are being swallowed today. This pill can track medication-taking behaviors, monitor how a patient’s body is responding to medicine, and detect a patient’s movements and rest patterns.
Some battery development is looking at the use of pigments found in cuttlefish ink. Conventional battery materials are not safe in-vivo unless they are encased in bulky protective cases that must eventually be surgically removed. The prototype sodium-ion battery uses melanin from cuttlefish ink for the anode and manganese oxide as the cathode. All the materials in the battery break down into non-toxic components in the body.
MES remains extremely well-informed of developments in this area, and is eager to discuss projects from OEMs that look to exploit “conventional” bio-resorbable materials, or the more ground-breaking advances in edible electronics.
Next week we can perhaps move onto making a miniature submarine!!