Dr James Vicary is the Co-Founder and Managing Director of NuNano, a company using innovative manufacturing techniques to produce high quality probes for atomic force microscopy (AFM). NuNano was one of the first companies to move into Unit DX. James joins Anna Fleming to discuss what makes AFM so useful, and what sets NuNano’s products apart from the rest.
What is AFM? What’s it used for?
Atomic force microscopy (AFM) is a nanoscale characterisation technique. It uses the interaction force between a sharp tip and a surface to build up a map of that surface with nanometre resolution. In basic terms, it’s somewhat like a record player – in a record player there’s an arm with a stylus at the end, which moves over the grooves of a record. In AFM we have a probe (a cantilever with a sharp tip on the end), which scans over the surface. Minute changes in the cantilever’s oscillation as it scans are detected using a laser beam reflected off the moving cantilever, to build up a map of the surface.
AFM was initially commercialised in the 90s and was used mainly in the semiconductor industry as a non-invasive method for quality inspection and failure analysis. Now it’s used to characterise all sorts of materials – polymers, ceramics, and it’s even filtering into the biomedical and life sciences sectors too. AFM is an incredibly versatile technique, because it can be used not only in vacuum, but also in air and liquid, so it can characterise biological specimens in their natural state.
So what issues are there with AFM? What is NuNano working to improve?
At the moment we’re focused on quality. There are two crucial issues that we’ve recognised – tip sharpness, and uniformity between probes. Tip sharpness isn’t necessarily about absolute sharpness (although typically the sharper the tip the higher resolution you can image at), but rather how often you get probes which aren’t as sharp as they should be, or are damaged or contaminated. We do a lot of inspection during our processing, ensuring that every probe we ship has a sharp tip that’s within the specification, and not damaged or blunt.
Improvements in uniformity focus on the mechanical properties of our probes – as they oscillate, the mechanical properties of the cantilever determine how well it works. People want to be able to replace a blunt or contaminated probe with a new one, and have it work as much like the original as possible. The key parameters that alter how a probe works are the spring constant and resonant frequency, both of which are largely dependent on the length and thickness of the cantilever. We use a different etch process which gives us much better control over these dimensions than other manufacturers, and that allows us to tightly control the uniformity of our probes.
How did NuNano start out?
I worked with AFM probes throughout my PhD at Bristol, so I know first-hand the frustration their unreliability causes. After I finished, I decided to learn how to make probes myself. I basically took two years where I taught myself the processes behind microfabrication. Then I made some unique and very niche probes that were used by our research group at the University of Bristol. Once I felt I had enough skills and expertise to be able to make something that would be widely commercially viable, I started producing prototypes.
The first couple of years were spent establishing a customer base, mainly through my academic network. I sent samples out and got people’s feedback, saw where the company was falling short, and worked on these areas. Once I had demonstrated that I had a product and a market, I was able to get investment, and that let me expand the team, and have dedicated production and commercial personnel; a whole team that covered the day to day running of the company, rather than just me doing everything. Now we have a fully-fledged production capability – with new batches being made every 3 weeks. This summer we had our first US sales, meaning we now sell in Europe, Asia and the US. We’re also starting to sign distribution agreements with companies in Japan and China.
What’s your plan now?
We want to expand our product range – at the moment we have two core products, both of which are silicon-based, but we want to move into softer silicon nitride probes, to target the life science industry, where softness is necessary because of the delicate specimens under study. We’re also looking to expand our commercial capabilities, by working with more distributors around the world, and supporting them to sell our products.
Ultimately, we want to see our products help as many researchers around the world as possible learn how materials look and behave at the nanometre scale.
For more information on NuNano, please visit their website.