The popular press has picked up on the publication of, Fabrication of zeolite–polymer composite nanofibers for removal of uremic toxins from kidney failure patients by a team out of WPI-MANA. Unfortunately, this article ties together many sensationalist components that are commonly seen with a new materials science. The researchers have looked at high surface area zeolites to see if they might be effective in detoxifying blood. They took some of those same zeolites and then used them in an electrospun nanofiber membrane to see if the performance persisted (it did – at 67% of the level of the zeolites out of the NF web).
The researchers then claimed that this would enable ‘wrist-mounted’ blood purification devices that would replace dialysis. This is a big jump.
There are some gaps between the current state of the research and the wrist-mounted device.
Gap 1: Zeolite performance
I’m not a zeolite expert, but there is no doubt that the heart of this device’s performance lies here in the zeolite component, and not with the polymeric EVOH NF web. The NF membrane is simply acting as the delivery scaffold to maintain the surface area of the zeolite and to ensure that the zeolites do not move about in the system.
The state of the art in electrospinning is more than sufficient to get the right zeolite into the right form factor – the challenge will be identifying the right zeolite and proving that authoritatively while addressing the other gaps listed below.
Gap 2: Spinning of the Zeolite-Enhanced Web
Scale-up of this process will be challenging, but the fact that it has been done already is a very positive indicator. Often times, working with academic groups, the challenge comes in transitioning the recipe for its first runs in an industrial setting. Many of the production and engineering variables that led to the the initial invention may not easily transition to production.
Ensuring that the zeolite mixes well with the EVOH in solution will be important – industrial scale agitation of the nanofiber precursor material will need to be used to keep it in suspension until it is electrospun. Clumping of the zeolite would reduce the surface area and hurt performance.
Gap 3: Device design.
The device would have to take blood out of the human body, run it through the NF web, and then return it to the body at the same pressure it was taken out. Maintaining the pressure of the fluid across the zeolite-enabled NF web will be important. I am skeptical that this can be done naturally with the blood pressure provided by the human heart – precision pumping and fluid handling are core technologies to enabling the performance of a traditional dialysis unit.
The zeolite-enabled NF membrane may be pleated or deployed in some other setting in order to minimize surface area and begin to address the next gap – product life.
Gap 4: Device capacity.
If we assume that the research confirms that the zeolyte performs well (Gap 1), that we can scale production reliably and cost-effectively (Gap 2), and that we can then get the NF web into an appropriate device (Gap 3) – what will the life of that device be? Capacity is something that is always a challenge to predict in filter design, and likewise it is difficult to anticipate how long the device here will function.
While there will be a lot of value in this product if it can get all the way to commercialization, it is crucial to evaluate the market opportunities for a 30 minute life device, where the user is frequently changing out cartridges, to one that can last for days or weeks.
As with any piece of scientific or academic research that is picked up by the mainstream media, there are always gaps in interpretation. This is a product that is likely 3 – 5 years away from some kind of in vivo testing and likely 10 – 15 years away from being a practical application, if it is able to cross the gaps listed above. The testing gap – in that there are unlikely common testing protocols for techniques that are so new, creates a series of challenges that will further slow adoption.
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