Health, Medicine, & Biotechnology

Low Friction Plastic Technology For Single-use Drug Delivery Devices

Start-up coefficient of friction and stick-slip (or “stiction”) elimination are dominant performance drivers in single-use drug delivery devices that have moving parts. RTP Company has completed a rigorous investigation that establishes and defines a new friction test to measure and compare plastic-against-plastic friction behavior that occurs at initial startup. This new test uses forces and speeds that characterize the action of injection pens, auto-injectors, stop cocks, inhalers, safety syringes and other devices. This paper describes the newly created friction test method, and its core data point known as Glide FactorSM, as well a series of tests to compare the friction behavior of select polymers and internal lubricants for use in single-use drug delivery devices. The use of internally lubricated plastics can eliminate costly secondary operations to apply a topical lubricant, reduce the total amount of silicone that reaches the patient via the device, and improve the overall quality of the device. The goal of this paper is to share a tribological database that enables device designers to screen plastic-on-plastic friction pairs to optimize safe and effective material selections.

Posted in: MDB, White Papers, White Papers, Coatings & Adhesives, Materials, Bio-Medical, Medical

How to Prevent Step Losses with Stepper Motors

While stepper motors are an excellent solution for many applications, a key concern is step losses. However, in most instances step losses can be prevented or corrected. It is important to remember that a stepper motor does not operate like a DC motor. This white paper from MICROMO engineers provides guidance to determine step losses or non-operation across a variety of applications.

Posted in: White Papers, White Papers, Mechanical Components, Medical, Motion Control, Motors & Drives

Optimizing Electronics for Medical Applications

Two years ago, in Medical Design Briefs, Derek Hunt offered some insight into the benefits of Complementary Metal-Oxide Semiconductor (CMOS) technology in the miniaturization of medical devices. CMOS has been around for decades and aside from the size benefits which will be discussed shortly, the technology also brings significant cost savings and performance improvements to the medical world. Readers who are currently engaged in the design of medical electronics already recognize this. It’s actually difficult to design such products today without incorporating CMOS devices. And because medical devices often contain many analog components, there remains one critical decision point designers must address and that is whether to design with standard off-the-shelf standard analog products or engage with a semiconductor company to produce a custom analog chip for the application.

Posted in: Features, Medical, Optimization, Electronic equipment, Medical equipment and supplies, Semiconductors

Relativistic Ion Tracks (RITRACKS)

Lyndon B. Johnson Space Center, Houston, Texas

Once astronauts venture beyond Earth’s protective atmosphere, they are exposed to the high-energy charged particles of galactic cosmic rays (GCR) and solar particle events (SPE), and secondary protons and neutrons. GCR are composed of ions, the great majority of which are protons (≈87%) and helium nuclei (≈12%). The heavy ions of atomic number greater than 2 comprise only a small fraction of the charged particles in the GCR, but they contribute significantly to the radiation dose and dose equivalent over time. Because of their ionization patterns in biomolecules, cells and tissues are distinct from terrestrial radiation, the resulting biological effects are poorly understood, and the health risks of these radiations are subject to large uncertainties.

Posted in: Briefs, Medical, Computer simulation, Medical, health, and wellness, Radiation

Medical Oxygen Concentrator for Microgravity Operation

Only ambient air and DC energy are required to operate the system.

John H. Glenn Research Center, Cleveland, Ohio

Supplemental oxygen delivery systems are vital to provide a critical life support respiratory function. Whether they are used for patients suffering from lung diseases or other illnesses, or astronauts donning an oxygen mask during a toxic spill or fire on a spacecraft, lightweight and portable oxygen delivery systems are in high demand. A lightweight portable oxygen concentrator was developed that can produce 1 to 6 lpm of pulse oxygen in a noiseless system that can be worn on the user’s hip or in a shoulder sling.

Posted in: Briefs, Medical, Life support systems, Medical equipment and supplies, Oxygen equipment

Lateral Displacement Device for Blood Cell Separation

This device has side microchannels where the particles are separated and collected.

Lyndon B. Johnson Space Center, Houston, Texas

Separation of particles based on size is one of the essential components in biochemical analysis, environmental assays, and industrial and biomedical applications. Filtration is one of the most frequently used techniques to separate particles. A mechanical filter can be used to remove, filter, or collect particles. This filtering and collection of particles can be used for sampling of particles, chemical detection, and/or biological cell analysis.

Posted in: Briefs, Medical, Particulate matter (PM), Medical equipment and supplies, Biomaterials, Particulate filters, Test equipment and instrumentation

Using a Blood Clot in Microfluidic Valving Applications

This type of valve is satisfactory for most microfluidic applications for on-chip blood analysis.

Lyndon B. Johnson Space Center, Houston, Texas

The lack of reliable microvalves impedes many lab-on-a-chip applications for blood analysis. On the other hand, blood clotting — the formation of solid blood aggregate to stop bleeding — provides a natural valving mechanism. It is therefore very attractive to use this mechanism for microfluidic control when blood is available. In fact, the blood clot has many interesting mechanical properties. For example, the fibrin fibers in blood clots have extensibility as high as 330% and an elastic modulus around 8 MPa. However, the study of implementing blood clots as an engineering material, especially in the MEMS area, is lacking.

Posted in: Briefs, Medical, Cardiovascular system, Fluids and secretions, Medical, health, and wellness, Valves

Drug-Encapsulated Prosthetic Enhancement

Lyndon B. Johnson Space Center, Houston, Texas

This invention places a drug delivery system inside a prosthetic implant to circumvent the physical issues encountered after fitting the implant. Implants being relatively large in size would be able to house the drug-carrying device inside them without compromising the structural integrity or the functionality of the prostheses. Capsules containing multiple reservoirs filled with different drugs could be released simultaneously. This application could further be extended to using such drug-carrying capsules in cardiovascular stents through which slow and sustained release of drugs could be achieved to prevent inflammation in the short term, and restenosis in the long term. Once the capsule has drained out, the drug inside will remain in the implant and can be considered a part of the implant for the future. The implant reservoir may also be refilled via minor surgery until needed.

Posted in: Briefs, Medical, Prostheses and implants, Pharmaceuticals

Portable Resting State Detection System Using Functional Near-Infrared Spectroscopy

Langley Research Center, Hampton, Virginia

The ability to distinguish between high and low levels of task engagement is important for detecting and preventing performance decrements during safety-critical operational tasks in the real world. Examples of such tasks include commercial aviation, monitoring for air traffic control, executing spacewalks, performing surgery, and driving. Since accident-causing errors can be made even by skilled professionals, the ability to monitor cognitive state measures for low levels of task engagement in real time could be useful for developing an “early warning system” for detecting and preventing performance errors before they occur.

Posted in: Briefs, Medical, Sensors and actuators, Reaction and response times, Personnel, Risk management

4 Steps In Selecting Fluid Connectors For Medical Device And Equipment Applications

With so many risks and options for connecting tubing in medical applications, it is important to have a simple and repeatable strategy for selecting the best connector solution. The process requires a thorough analysis of the application in order to ensure connectors will be compatible with the physical, chemical and biological environment, and be easy to use and help prevent misconnections—whether the application involves connecting air lines for a blood pressure cuff, connecting reagent supplies to a blood analyzer or making critical connections between a patient and heart-lung machine.

Posted in: MDB, White Papers, White Papers, Medical

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