Chemical Technology November 2015

Blurring the lines between nanotech and biochemistry

by Gavin Chait

The walls, they no longer bounce the way they used to. When I was younger, I would launch myself at them, flinging myself across the court to reach the squash ball, ricocheting off them to reach the next shot.

N ow. The walls are harder. Much less forgiving. I realised the steady progression of time and bone-damage when I leapt, achieving a horizontal position one metre above the floor, and concluded – while still up there – that this was not going to end well. It didn’t. Doctors say I should, eventually, be breathing unaided once more. Playing the cello, they apologise, is out of reach. Good thing, I never tried it before. But still, there must be something we can do about all this lack of dexterity and volatility that comes with ageing. Let’s start with all those muscle and joint injuries and get more intimate from there. My knees could definitely do with what Korean Scien- tists at the Center for Nanoparticle Research, Institute for Basic Science (IBS) have come up with. They have created a ‘fabric’ made of ~150 nm diameter silver nanowires in an interlocking coil, and embedded in elastic material. This conductive fabric can be linked up to a small battery and provides direct heating over and around the joint. Better still, because it is light-weight, wearable, and breathable, it can be worn while running around. This is great news for squash players and those heading to the Arctic to climb mountains, or something. The question is going to be how durable such thin silver wires can be under stress, and I imagine this goes under the heading ‘needs work’. Silver, in my experience, has a tendency to break rather easily. However, beyond all the hype of nanotechnology in circuitry or providing weird properties, this is a fairly simple implementation with direct applications. It’s a wonder it hasn’t come sooner. Nanowire devices have been around for a while. Think

coronary stents. But these are now being used in more subtle ways. For example, a medical team from the Wyss Institute at Harvard University and the New England Center for Stroke Research at University of Massachusetts, have de- veloped a technique to re-vascularise (ie, restore bloodflow) to a vessel obstructed by a clot. They use an intra-arterial stent to open a channel through the clot and then inject a nanotherapeutic. “What’s progressive about this approach is that the temporary opening of a tiny hole in the clot — using a stent device that is already commonly used clinically — results in a local rise in mechanical forces that activate the nano- therapeutic to deploy the clot-busting drug precisely where it can best do its job,” says Donald Ingber, Wyss Institute Founding Director. And bone repair is being speeded up with 3D bioprint- ing which mixes biocompatible gels with stem cells and active proteins. This is where things take an odd turn.  When we think of nanomaterials, we (I) tend to think of things that are – in some way – manufactured. It may be chemically, like nanotubes microprocessors, or even machined. The active agent in such production is, though, human. What happens when we use actual living organisms to manufacture novel nanomaterials and tools? Is that biotech or nanotech? Engineering or biology? It doesn’t necessarily matter philosophically, but there are practical implications. Back in 1986, Eric Drexler imag- ined a classic end-of-the-world tale in “Engines of Creation”: “Imagine such a replicator floating in a bottle of chemicals,

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Chemical Technology • November 2015