Electroactive Material for Wound Healing

The Electrode Gel Bead technology was developed to address specific challenges for crewed spaceflight in the event of medical intervention where bioelectric monitoring or stimulation is desired. As mentioned, conventional electrode gels are traditionally dispensed from a tube onto an electrode, then washed off and discarded. For spaceflight applications, consumables of this nature are avoided due to mass and volume constraints, and to refrain from introducing solid contaminants into a closed spacecraft environment. Electrode Gel Beads are versatile within electrophysiology applica-tions and can also be used for bioelectrical stimulation. Systems designed to electrically stimulate the body such as transcutaneous electrical nerve stimulation (TENS), and various brain stimulation devices, could benefit from this technology as electrode gels can evaporate causing electrodes to overheat and irritate or burn the patient’s skin. Electrode Gel Beads could solve this issue when correctly calibrated for the application. To create a bead’s interior solution, a water/electrolyte mixture is calibrated with a specific molar concentration to create the necessary resistance for a specific electrophysiology application (different methods require a gel with different resistances such as ECG, EEG, etc.). Next, the solution is absorbed into an absorbent silica-based hydrogel bead. Hydrogel beads contain crosslinked polymer networks that can absorb and retain significant amounts of water without dissolving. They can absorb and retain significant amounts of the solution but maintain their structural integrity. After absorbing the solution, the hydrogel bead containing the solution can be affixed to an electrode and function as an electrode gel. Terrestrial applications for the Electrode Gel Bead may exist in inpatient, outpatient, and in-home healthcare usage where mess-free, reusable, ease-of-use, and electrical signal quality attributes are desired. This technology could also have applications in hydrogel sensory materials, such as wearable sensors.

Puncture healing melt blends were developed by melt blending self-healing polymers with non self-healing polymeric materials. The self-healing polymeric materials consisted of Surlyn&#174 8940, Affinity&#8482 EG 8200 G, and poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile) or Barex&#174 210 IN. The non-self-healing polymeric materials consisted of poly(ether ether ketone) (PEEK), LaRC phenyl ethynyl terminated imide 330 (LaRC PETI 330), and Raptor Resins Bismaleimide-1 (BMI-1). Puncture healing blends were also prepared with chopped glass and chopped carbon fibers. The overall goal was to develop a product with superior properties relative to either of the starting materials. The melt blends were prepared in varying compositions to optimize desired properties of the resulting matrix. Ballistic testing was conducted to determine the self-healing characteristics of several developmental polymers subjected to micrometeoroid type damage.

In space there are a limited number of care providers, and those providers are not always clinicians with extensive medical training. Space travel also has limited room to provide care and limited consumables. The Human-Powered Ventilator is compact, portable, and easy to assemble. It is designed so that users can implement hand and arm movements to pump the bellows between two hinged, clamshell-like panels back and forth to provide positive pressure ventilation to the patient. A light spring is incorporated into the design to assist in expanding the bellows, drawing air out of the patient’s lungs, and reducing the physical load on the operator without compromising the tactile feel necessary for proper usage. The airflow can be supplemented with prescribed medical vapors, oxygen, etc. via standard industry fittings. The Human-Powered Ventilator is TRL 6 (system/subsystem prototype has been demonstrated in a relevant environment) and it is now available for your company to license. Please note that NASA does not manufacture products itself for commercial sale.

Friction Pull Plug Welding (FPPW) is the process necessary to plug the hole that is left behind as a friction stir weld (FSW) joint is completed and the pin tool of the welder retracts from the joint. FPPW involves a small, rotating part (plug) being spun and simultaneously pulled (forged) into a hole in a larger part. Much work has been done to fully understand and characterize the process and its limitations. FPPW worked very well for building large rocket sections such as the circumferential welds of the upper stages of NASA's Ares rocket, and to repair the external tank. Engineers were challenged to adapt FPPW to accommodate the thicker plates new alloy combinations of the SLS. The new hybrid plug solves the issue of the plugs snapping due to the increase torsion and moment stresses when joining thicker plates. The new hybrid plug, with a steel shank, makes FPPW more practical and robust. The new plug has been used to make space-qualified parts at NASA, and the plug welds are as strong as initial welds.

This innovation utilizes a tri-layered structure, comprised of solid plastic front and back layers sandwiching a viscous, reactive liquid middle layer. Combined, this system provides rapid self-healing following high velocity ballistic penetrations. Self-healing in the front and back layers occurs when the puncture event creates a melt state in the polymer materials and the materials melt elasticity snaps back and closes the hole. The viscous middle layer augments the self-healing properties of the other layers by flowing into the gap created by a ballistic puncture and concurrently solidifying due to the presence of oxygen. Thus, this innovation has two tiers of self-healing: a puncture-healing mechanism triggered by the projectile and a second mechanism triggered by the presence of oxygen.