First talk was by microbiologist Jonathan Edgeworth of Guy’s & St. Thomas hospital. His priority was on a rapid test that could avoid overprescription of antibiotics for patients with relatively mild symptoms. Some tests (CRP, WBC, Procalcitonin) that could be used in PoC setting are already available but are hardly used.

Second talk by Naomi Stanton gave a primary care perspective: Again emphasis is on avoidance of overprescription of antibiotics. 80-90% of antibiotics prescription in UK is in primary care – but there are large variations in Europe in prescription behaviour that do not lead to changes in disease pattern. High need for a test with high negative predictive value – reassuring patients that they do not need antibiotics.

It needs to be taken into account that any PoC tests need to provide additional data that can help decision making in conjunction with GP examination and patient history. GP has a maximum of 10 minutes to see a patient, so all tests have to fit in that timeframe. If longer then test needs to be cheap/simple enough to be done before they see the GP, but in that case the test must also be cheaper since it will be done more pre-emptively (e.g. anyone presenting with cough gets tested).

Penny Wilson (TSB) on the calls: TSB supports from TRL3 (proof of concept) to TRL6 (demonstration of product potential). So no support for basic research, and no support for commercialisation. The two separate calls for SEPSIS are for collaborative R&D project and require matched funding. SEPSIS1 is about detection and identification of pathogens, and projects are expected to deliver a demonstrator product or service –this is the area of highest interest for me personally.

SEPSIS2 is about biomarkers for sepsis management. In the literature 170 markers are shown, and in scope are combinations of markers and algorithms to derive information from the combined panel. Doesn’t have to lead to product in this call – it is enough to advance the body of knowledge.

I intend to use it for small series of prototypes, using aluminium moulds cut on my mill - allowing me to make up moulded prototypes within a day. I think it will be particularly helpful to come up with small series of prototypes for disposable test cartridges. I’ll be experimenting soon to make some buttons for my CHIP-1 design.

It accomodates fairly large moulds (100mm x 75mm), and Travin indicates a maximum shot weight of 21 grams. The vice that clamps the mould halves together certainly looks very solid, and also operates an ejector plate making the TP-2 more user-friendly than the “Gingery” type scratchbuild injectors.

The discussion on whether or not there’s money in razors or razor blades (or printers/ink cartridges etc.) is often based on a assertion attributed to King Gillette - that there is no market for razors, only for razor blades - and that therefore it makes sense to sell the razors cheaply and make profit on the blades. If that principle was universally valid it would be very difficult to make money on digital cameras, yet still there are plenty of companies selling those!

I just came across an interesting blog post on the subject, which is also very topical for diagnostic or measurement instruments and their associated cartridges or consumables. What the argument boils down to is that the cheap razor, expensive blades argument does not serve to lock-in a user to your blades - on the contrary: if you give the handles away, the user has no switching costs.

A better example for diagnostic instruments could be the mobile phone business models: A full-service contract including a number of test cartridges per month as part of a rental agreement for high and medium volume users, and a pay-as-you go model for occasional users. These two business models lead to differing design priorities for the high and low-volume instruments.

For the montly rental model - which was the “pay per click” model used by copier manufacturer Océ when I worked there in the early nineties - it pays for the vendor to make the instrument as reliable as possible even if that increases the production cost, as this will be earned back in lower maintenance. For the PAYG instrument the pressure to reduce production cost will mean making compromises on longevity of the instrument.

If you’ve got IP on a new detection technology there is usually a choice of whether to implement this in the instrument or in the cartridge (or in both). In that case it makes sense to explore the different scenarios for both occasional and high-volume users. It might be that the best instrument offering for your technology is the combination of a completely disposable instrument for casual users, and a high-end instrument with simple consumables for the high-volume user on a rental agreement. Looking into the options should be part of your product definition efforts.

I’m currently reading the book “Angels, Dragons & Vultures” by Simon Ackland. The book is written for (aspiring) entrepreneurs who are looking at raising venture capital for their start-up business. Ackland has been a VC fund manager (Vulture) and angel investor, and perhaps with this book he’s looking at becoming a Dragon (publicity-seeking angel). I found it a very enlightening read - certainly worth the 10 pounds.

Many aspects of instrument design are not unique for each instrument. For this reason I’ve made CHIP - a Configurable Handheld Instrument Platform. CHIP provides a convenient base design from which it is very easy to construct specific product demonstrators for new sensing technologies.

CHIP is small (100 x 48 x 20mm, about the size of a mobile phone), powered by a high-capacity rechargeable battery and has a clear 160 x 128 pixel OLED colour display. It is based on the mbed module so has all the advantages of rapid software development and ease of program updates in the field.

To turn CHIP into a product demonstrator we’ll need to add a client-specific Sensor Module. As the sensor module design does not have to take into account battery management, display and button hardware, and file system we can concentrate on those elements that are unique to the specific sensor technology, and only integrate those into the Sensor Module - which can usually be very compact. Sensor Modules are plugged into a slot in the top of the CHIP case - the rendering shows a possible implementation of a chemical test strip reader.

Once the design of CHIP is finalised and I’ve build and tested a few units I will put more information onto the Panchromos website. In the meantime don’t hesitate to get in touch if you’d like to know more.

mbed microcontroller module

Prototyping embedded system with mbed to me has a number of advantages: The first is that the IDE and compiler are online, so there is no software to install or more importantly to keep up to date. Besides the IDE, the mbed.org site also gives access to a large number of code libraries, the user manual, and the user forum. When I wanted to implement a small graphic colour display it took me only a few hours to find a usable library on the site and create a program around it that suited the first version of my prototype.

The second advantage is that when plugged into a USB port the mbed shows itself on the PC (or Mac, but haven’t tried that) as a flash-drive. New firmware can simply be dragged onto the device - on power up the module will execute the most recently dated *.bin file - which also means that a firmware update can be easily rolled back. This allows my clients to update the firmware on the prototype systems I deliver without installing additional hard- or software, and to choose between multiple versions of firmware - e.g. use one version for a demo and another to run tests.

The third advantage is the relatively small size of the mbed module - it’s a 40-pin DIP module measuring 53mm long x 30mm wide x 9mm high, and that height is mainly due to the mini-USB socket. This allows me to integrate mbed modules as components in product demonstrators that are representative of series-produced instruments.

The fourth advantage is that any code written for the mbed module will run with trivial changes on a bare LPC1768 chip on a custom PCB. This facilitates going from prototype to series production. Although the mbed modules are actually very reasonably priced at around £40, the ability to easily move to the £5 bare chip in production is very appealing.

Where the mbed module doesn’t score that well: For starters only 32 I/O lines are brought out from the 70 of the chip. Most of the mbed routines and APIs put flexibility and ease of use over raw performance. And there’s no real debugging support.

But I know I’m going to be using mbed modules quite extensively!

SLAs are linear arrays of one or two rows of GRIN lenses (rod lenses). They form a non-inverted 1:1 image built up from overlapping contributions from a number of rod lenses. Because of these overlaps an SLA can only be used at unit magnification - at any other magnification the overlapping images would be out of register. The manufacturer Nippon Sheet Glass isn’t too clear in their information on this page - a better attempt is this page by TAOS.

I recently built an optical breadboard for a chemical detection device in which I again used this interesting part, this time to project an image of a sample onto a linear photodiode array at a width of only 10mm. Using an SLA enables a very compact design - the total object-to-image distance (track) of the smallest SLA-20DG is 9.1mm, with the SLA itself measuring 3mm wide and 4.5mm high. Image quality in terms of MTF and depth-of-focus are better for SLAs with higher track length, at the expense of compactness.

It is not that straightforward to prototype with a small piece of SLA - minimum order was 2 pieces of 127mm long per SLA type - which had to come from Japan taking 4 weeks. That means I’ve now got some stock of the SLA-20DG and SLA-12DG so I can quickly build prototypes with those. They were quite expensive too - but for production quantities the price comes down rapidly, as is clear from the fact that SLAs are used in consumer scanners and printers.

Dr. Ian Lawston - chief scientist at the Dstl detection department - discussed the performance requirements for detection technologies. Apart from the obvious needs for sensitive detection of as many threats as possible, he emphasised that currently improvements are most needed not in the detection technology itself, but in the area of sample collection and processing. Real-life samples are inhomogenous, messy and full of contaminants - and in many cases sample prep will take far more time and require far greater skill then doing the actual detection.

Supt. Steve Doel of the Police National CRBN Centre stated that at present the police does not have any approved means of detecting biological threats - so there is a very strong need for robust, cost-effective solutions which can give the level of confidence required for typical police scenarios (e.g. evacuation or quarantine of airports).

There were a number of presentation on various detection technologies. What struck me is that these tend to be stand-alone systems - the raw sensor data is interpreted in an integrated device and processed into a simple recommendation without taking other factors into account. It could give significant benefits if instead all of the different detection modalities would feed their raw sensing data into one intelligent processing unit that would base it’s output on the combination of sensing results. This would require a common language to express the raw sensing data, and the need to build up combination profiles for certain threats. Any comments?

Unlike most current production technologies the new process creates carbon nanotubes from the solid phase - from graphite. This means that production is far more efficient and production capacity is greatly increased.

Prof. Fray’s team has also shown that they can modify the production process to produce carbon nanotubes that are filled with metals such as tin. The use of these filled nanotubes in Li-ion batteries has shown to greatly increase their capacity per unit weight - a very important consideration for future generations of hybrid or all-electric vehicles.