VitalISE for Mars

Extremophile sensors in the search for extremophile forms of life.

Previous Next

• MATERIAL EXPLORED: Aqueous Silver (electroplating), Photopolymer
• PROPERTIES POSSESSED: Ion Selective, Miniaturization, Extreme-environmental resistance

In 2008, NASA Mars lander, Phoenix, transmitted pictures of crystal white shards of subsurface ice from the Dodo-Goldilocks dig site. Equip with on-board wet lab capsules, Phoenix further fed our curiosity with data on the ionic composition of this soil. Life as we know it is mediated by water, and its universal ‘currency’ is salts; responsible for osmatic retention, metabolism and even the highest functions of mental thought. The pressing question remained, did this hostile rock planet once breathe life? And the ever more urgently, could this landscape comprise of compounds to support human life in our future?

On our team, I fabricated extremophile sensors to search for evidence of extremophile lifeforms. On Earth, Ion Selective Electrodes (ISEs) are used ubiquitously (most commonly pH meters), but we needed counterparts with the robustness for space travel and future Mars missions. I worked on iterative designs for miniaturized arrays of 80 unique sensors, fit on a circuit board the size of a Popsicle stick. These galvanic cells required fabrication of tiny electrodes and selective barriers, so I employed methods of electroplating thin layers of silver (aq. AgCl), followed by photo-curing ion selective resins. I cycled through materials, from sealants to Navy ship paints, to find things that could survive a full 235⁰F range, massive vibrations and the corrosive properties of water.

Dealing with leakage, a highlighted breakthrough came as the idea to invert our fabrication process (and the shape of our sensor). Instead of depositing layers of polymer into wells, we could attain the same effect via an additive ‘candle-dipping’ process, which consistently created sensors as tiny bulbs on the tips of wire!

• Partnered with Harjes, Bickford and Reiter at Draper Laboratory.

Bio-MEMS

A way for circuits to listen to the cyphered signals of our health, one protein at a time.

Previous Next

• MATERIAL EXPLORED: Protein and Macromolecule Adhesive Coatings, Gold and Glass Substrates
• PROPERTIES POSSESSED: Small volumes, rapid responsiveness, pH regulated 'reset'

MEMS and biology go together like peanut butter and jelly! In other words, the scale of these micro-electromechanical sensors coordinate to that of natural protein and macromolecule interactions. Thus, with microfluidics, we can facilitate communication between worlds.

Our BioMEM is an Adhesive Stress Electrostatic Sensor (ASES), a circuit for point-of-care Tuberculosis detection. ASES consists of a membrane coated with antibodies, which we flow micro-volumes of human blood serum past. The membrane operated as a capacitor, so when Tuberculin antigens bound, the small deformation of this added thickness it would create a measurable voltage change. Thus, it was a transducer to convey the binding energy of proteins into electrical signal, and ultimately diagnostic information.

I worked to tame the biological aspects of the membrane; how to create protein arrays of strong, selective bio-affinity. For testing purposes, I used Surface Plasmon Resonance to observe nano-thicknesses of material adhering to the protein surfaces I created. Images above show my view of the gold substrates within in our initial fluidics chamber. Optically, the spots turn from black to reflective white when analyte bound. This would eventually relate to the stress on a capacitance membrane, in a micromechanical sensing method.

Pushing capabilities beyond the initial application for diagnostics, I explored reversible binding limits, so the senor could continuously switch between on/off without a drifting baseline. This could relate to numerous uses, including continual glucose monitoring for diabetics.

• Partnered with Williams and Tupper at Draper Laboratory.

PhageFlag

Recombinant bacteriophage made into rapid bio-sensors.

• MATERIAL EXPLORED: Phage Genome, Bacterium Host (E. coli DH5a, O157:H7, Bordetella pertussis)
• PROPERTIES POSSESSED: Rapid responsiveness, Self-replicating, Interfaces with Lateral Flow Assay

• Partnered with Zorychta, Moshasha. Advised by Kelly PhD, Herr PhD, Hewlett MD and the Coulter Translational Research Foundation.

REDFLOW.

Shaping a liquid sensing organ.

Previous Next

• MATERIAL EXPLORED: Plastic Molding, Geometry
• PROPERTIES POSSESSED: 'Soothing' Shapes, Bifurcation, Salt Exchange

Consider a liquid-based sensing material. One made up of countless part which are constantly in motion and communication; parts that collectively react to the shape which they are contained in and move through. Under conditions they can synchronously transform, changing their medium from liquid to solid.

Still a lofty goal for synthetic materials, this is a remarkable property of blood. Blood is comprised of suspended sensors and receptors. It has complex stress cascades, triggered by chemo reporters, which allow it ‘awareness’ to its environment and the ability to coagulate. Our challenge was to experiment with blood responsiveness and create shapes conducive for its flow. Specifically, we hope to minimize clotting and preserve blood health during dialysis, the artificial kidney filtration process in which patients’ blood is currently shunted through cartridges that look like a car mufflers.

Alongside a power team of MechEs and modelers, I built and tested flow cells. We used porcine blood, achieving in vivo pressure by elevating our starting reservoir 5 ft above the benches (rocking precariously, to keep the blood in motion). We ran blood through our prototypes, ranging in geometric shape and noted how the liquid responded. While right angled paths could create micro-clots in minutes (!), sampling from the vascular shapes found in the body could encourage laminar flow and limit turbulence. Our muse became the kidney itself. Our design made use of natural bifurcations and curves to shape blood into smaller ducts, mimicking its fine capillary structure.

We named our largest clots like hurricanes. Alfred…Beatrice…Claud.

• Partnered with Harjes, Prantil-Baun and team at Draper Laboratory.

SURGE

Bringing medical practice closer to local settings with honey and wax.

Previous Next

• MATERIAL EXPLORED: Alternatives to Hospital Disposables
• PROPERTIES POSSESSED: Local, Biodegradable, ...Delicious (and so much more!)

For one warm, sticky summer in Virginia after graduation, I apprenticed as a bee keeper. I quickly became enthralled by these hive collectives, and happily began to integrate them into my design work.

That fall, I began communicating with a nurse practitioner in Kigali, Rwanda. We discussed challenges faced at the national hospital, CHUK. There is a growing paradigm towards disposable components in medical equipment designed for the first-world, which creates a continual reliance on donations in secondary hospitals. For instance, new, smart defibrillation systems are only compatible with single-use AED electrode pads, so without a supply of name-brand pads the entire machine is rendered useless. This means that with modernization, their practice becomes less self-sustaining and more reliant on charity.

Meanwhile, a second practitioner pointed to a thriving bee-collective in the same region. They had surplus honey and wax, and need to invent new products for economic viability – hence began an exploration of bee products in the hospital. We first engaged the nurses and beekeepers in a ‘Photo Novella’ to document and illustrate their daily processes, respectively.

I assembled a team to work with samples of wax and honey we received from Rwanda. Wax exhibited properties of being air and water sealant, and conforming to shape with body heat, electrically insulating and highly stable. Honey exhibited properties of low water activity, microbial inhibition and varying electrical conductivity due to electrolytes. We learned from the local EMS/Rescue Squad that electrode pads consist of a backing which supports a conductive gel which can quickly adhere to the chest to deliver a distributed shock. Our prototype became a kit to deconstruct and rebuild single-use AED pads for reliable multiuse. One design switched out standard pad gel/backing with viscous honey and the conforming structure of wax.

The approach created rich creative collisions and brought a medical practice closer to its local settings. It was a semi-finalist in the 2014 E-Cup Social Entrepreneurship Pitch competition.

• Partnered with University Central Hospital of Kigali (CHUK), Univeristy of Virginia Coulter Foundation, Health UnBound. Worked with Jesse Silver, David Chen and E-Cup Team.

LVAD UP

Fabric forms to bear the weight of a mechanical heart.

Previous Next

• MATERIAL EXPLORED: Fabric, Wire
• PROPERTIES POSSESSED: Support, Stabilization, Aesthetics

The human muscle and bone structure is sculpted to distribute weight efficiently and carry itself through movement. But what if you were to add 8 pounds of extra parts?

I and a fellow biomedical engineer came to know several patients with a pneumonic heart pump called the Left Ventricular Assist Device (LVAD). Originally designed as a temporary salvage for patients with late-stage heart failure, the continual shortage of donor organs means people rely on the LVAD for up to ten years. The LVAD pump is integrated within the chest cavity, but attaches via an abdominal wire-tube to a controller and two battery packs carried externally at the waist. LVAD holsters are extremely important, as dropping the external hardware could stop the unbeating 'heart' or yank on the internal system and tender abdominal outlet.

Thus, the bulky machinery presented as a blessing and a debilitation. Many patients who we interviewed explained it as a new burden that they carried constantly. Issues with the rudimentary vest included discomfort, loose fitting and at risk of snagging. Surprisingly, painful self-consciousness was just as pressing; ranging from the ‘ugliness’ of showing up to work in the same vest each day, to shying away from public places while looking, most extremely, like a ‘like a terrorist’. Some of the first bionic humans are reduced to wearing a ‘fishing vests’ holster with wires sticking out.

Guided by the UVA Cardiac Department, we addressed material, form, and aesthetics. Rough designs from cut fabric gave us ideas of how to distribute and stabilize mock-weights. We experimented with elastics and underwire, and wore a few of our designs for hours at a time (although, It was nothing like Project Runway).

• Partnered with with UVA Cardiology Department, BME Advanced Design and Harding.