Low cost nanoneedle

[Mino]

Hello everybody. I think most of you know that the nanoneedle research seems to be stuck in limbo. I have an idea that might just work. It may be not a panacea, but I think it's worth a try. As you may know, the original nanoneedle is built using conventional microfabrication processes on a silicon wafer. What I propose is to build the nanoneedle on a flexible (plastic) substrate using this service https://www.pragmaticsemi.com/create-more/designs. There is not a lot of information available on the process that pragmatIC uses (at least not as much as I'd like!), but from the information I have been able to gather, building a nanoneedle should be feasible (maybe with some tweaking of the design of the latter). If (and that's a BIG IF) the nanoneedle could be built with this process it could be made so cheap to make it disposable.

I know this sounds too good to be true, and that's why I ask for your opinion. If any of you has an electrical engineering background or is a microfabrication expert, please do chip in! I've already tried to contact Ron Davis and Dr. Esfandyarpour, to no avail. Probably they are submerged by emails, and they didn't notice mine, or maybe they just think I'm spam .

I'll post more information on the process that pragmatIC uses later, I have to go now, sorry.

 

[Mino]

Some resources about PragmatIC's process.
https://www.pragmaticsemi.com/
https://www.nature.com/articles/s41928-020-0437-5 (chip built with PragmatIC process)https://www.pragmaticsemi.com/

I also want to add that I'm not affiliated with PragmatIC in any way. This is not a covert advertisement. I just think that their process could be used to build a cheap nanoneedle. That's all.

 

[Wishful]

Not much information readily available on either pragmatic's process or one what sort of nanoneedle ME research needs. If it requires thick silicon to be etched deeply to form needles, a plastic substrate may not make it any cheaper or easier (possibly unworkable). If it can work, and it's significantly cheaper than regular foundrys, then it might help. I'm not sure whether the nanoneedle fabrication is the limiting factor in the ME research with it; it might be minor compared to salaries and lab costs.

 

[Mino]

Not much information readily available on either pragmatic's process or one what sort of nanoneedle ME research needs.

PragmatIC uses a 800nm process with 4 metal layers. It seems good enough on paper. I agree on the second part.

I'm not sure whether the nanoneedle fabrication is the limiting factor in the ME research with it; it might be minor compared to salaries and lab costs.

That's what I'm wondering too. There is no way to tell at the moment where the bottleneck is (other than NIH). The nanoneedle, in its current incarnation, is a relatively expensive device, and it has to be reusable. A nanoneedle built on a flexible substrate has the potential of being much cheaper, disposable and mass producible. A disposable nanoneedle would eliminate the cleaning steps between runs, for example, this alone makes the device attractive IMHO.
Of course all of what I've written above is speculation, but I don't think it's wild speculation.

 

[BrightCandle]

This is the Ron Davis paper on the nanoneedle paper and gives some details about how a nanoneedle assay that measure works - https://www.pnas.org/content/116/21/10250

There is enough in this to likely design such a device given the electrical design as well as detail of fabrication is diagrammed. It is quite a small wafer they are using and features seem to be measured in 10s of micro meters. Gold and oxide is interesting however especially given its vertical spikes, that is going to require a very specialist manufacturer, it is a custom process they seemed to use.

 

[Wishful]

The spikes seem to be horizontal, rather than vertical, the way I imagined it. I wouldn't even use the term 'needle'. "Nanoelectrode array" seems more appropriate. From what I've read of fabbing, it seems simple enough. I have no idea whether PragmatIC's fab can do it, and whether it would be cheaper.

You could contact PragmatIC yourself, include the link to Davis' paper, and ask them if they could do it cheaper. I expect they want customers and would be willing to contact Davis directly if they think they can get his business.

 

[junkcrap50]

Ron Davis was working with manufacturers in China to make the nanoneedle. I don't think they finalized a design or paid for a final product. But they were optimizing the design and far enough to enter discussions with manufacturers.

 

[Alvin2]

Ron Davis was working with manufacturers in China to make the nanoneedle. I don't think they finalized a design or paid for a final product. But they were optimizing the design and far enough to enter discussions with manufacturers.

I hope he goes with cash on delivery.

 

[Mino]

The spikes seem to be horizontal, rather than vertical, the way I imagined it. I wouldn't even use the term 'needle'. "Nanoelectrode array" seems more appropriate.

Correct.

From what I've read of fabbing, it seems simple enough.

It is. A nanoneedle is, essentially, a pair of very, very tiny multimeter probes held very, very close together.

I have no idea whether PragmatIC's fab can do it, and whether it would be cheaper.

That's the big question.

You could contact PragmatIC yourself, include the link to Davis' paper, and ask them if they could do it cheaper. I expect they want customers and would be willing to contact Davis directly if they think they can get his business.

I don't think that's advisable. I think contacting Janet Dafoe first is a better option. She could relay the information to Ron Davis and Dr. Esfandyarpour.

 

[Mino]

Some highlights from the latest PragmatIC paper:

Fabrication
Process parameters and statistical variations of TFT parameters are summarized in Extended Data Table 2. FlexLogIC is a proprietary 200-mm wafer semiconductor manufacturing process that creates patterned layers of metal-oxide thin-film transistors and resistors, with four routable (gold-free) metal layers deposited onto a flexible polyimide substrate according to the FlexIC design. Repeated instances of the FlexIC design are realized by running multiple sequences of thin-film material deposition, patterning and etching. For ease of handling and to allow industry standard process tools to be used and sub-micrometre patterned features to be achieved (down to 0.8 μm), the flexible polyimide substrate is spin-coated onto glass at the outset of production. The process has been optimized to ensure that the thickness variation is substantially less than 3% over a lateral distance of 20 mm. Thin-film material deposition is achieved through a combination of physical-vapour deposition, atomic-layer deposition and solution-processing (for example, spin-coating). Substrate processing conditions have been carefully optimized to minimise film stress and substrate bow. Feature patterning is achieved using a photolithographic 5× stepper tool, which images a shot that is repeated at multiple instances across the 200-mm-diameter wafer. Each shot is focused individually, which further compensates for any thickness variation within the spun-cast film. The technology measurements were carried out using process control monitoring structures.

Some reflections:

• they advertise their metal layers as "gold-free". I guess it's an advantage for them (it reduces costs), but the nanoneedle uses gold as the material for its electrodes (probably because gold doesn't oxidize very easily). Still, I don't think it's a deal breaker, if I remember correctly an iteration of the nanoneedle had electrodes made out of polysilicon, and other materials could be tried as well. They could also support gold metal layers, who knows.
• their process can accommodate enough transistors that some processing onboard is feasible. I don't think they have an analog process yet, but it's in the roadmap. Potentially one could fabricate the electrodes, the ADCs and a simple processor directly on the plastic substrate, then add the microfluidics on top and have a complete solution. Then it's only a matter of designing a simple device that interfaces with the chip to upload the results to a smartphone or a computer.
• while I'm not sure that PragmatIC can build a nanoneedle as described in the PNAS paper, their process could probably be adapted, or the nanoneedle design could be tweaked to work on their process. The guys at PragmatIC seem to be quite brilliant, I'm sure they are also reasonable and they would be open to a new market for diagnostics. In fact a diagnostic device is given as an example in one of their papers (I'll quote the relative passage in the next post, let me find it).
• for those who are not familiar with the industry, building an entire processor on a flexible substrate is kind of a big deal.

Here is the link to the full paper: https://www.nature.com/articles/s41586-021-03625-w

 

[Mino]

From https://www.nature.com/articles/s41928-020-0437-5 (for the full paper, go to the website that shall not be named (libgen))

NFPE stands for "natively flexible processing engine".

NFPEs are of potential use in emerging applications such as
smart packaging, FMCG and mass-market healthcare. The common
characteristics of these markets are that the relevant products
are low in cost, high volume and have short lifetimes. For example,
a smart label with a flexible e-nose sensor array and ML NFPE
could be attached to a meat package to monitor food quality and
safety. The shelf life of such a product is normally a few days, after
which the package (along with flexible electronics components) is
disposed of or recycled.
Alternatively, a smart wound dressing containing flexible temperature
and e-nose sensors attached to an ML NFPE could perform
real-time monitoring of the wound by processing sensor
outputs and predicting the healing of the wound. The lifetime of
the dressing is similar to the meat package (a few days), but here the
predicted output could be a binary one, signalling the healing status
as ‘healed’ or ‘unhealed’. The performance metric would be the prediction
accuracy of the healing status decision, which may be very
high (over 95%, for example) to avoid false positives, because the
prediction outcome may be safety-critical for the patient. A number
of ML algorithms would need to be modelled on the training datasets
to find the best-performing ML model to meet the performance
requirements of the application.

Emphasis mine.

 

[Pyrrhus]

Related discussions:

A nanoelectronics-blood-based diagnostic biomarker for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
https://forums.phoenixrising.me/thr...elitis-chronic-fatigue-syndrome-me-cfs.76073/

Difference Between the Nanoneedle & Other Impedance Analyzers?
https://forums.phoenixrising.me/thr...e-nanoneedle-other-impedance-analyzers.80155/

Nanoneedle: can impedance measures really indicate the benefits of a drug?
https://forums.phoenixrising.me/thr...really-indicate-the-benefits-of-a-drug.82135/