Under VTT leadership, an international Photosens research project developed a sensor solution, in which sensors printed on a polymer platform measure concentrations of one or multiple substances. The application opportunities for this new technology are huge and the markets for applications based on it are only beginning to open.
Coordinator of the project at VTT, Research Professor Pentti Karioja, shows a roll of sturdy polymer film with small squares. The roll contains nanophotonic sensor circuits printed on a polymer platform.
– In the development, we focused specifically on mass production techniques, by which large amount of sensors can be made. We wanted an easy-to-handle sensor solution that is cheap for both the manufacturer and the consumers, he explains.
In other words, the sensor platform is ready, but it does not suffice on its own. Jussi Hiltunen, who acts as researcher at VTT Oulu, shows a small metallic reader, which is a prototype. He places a sensor inside the reader and the camera technology incorporated into the device deciphers the information collected by it.
– The long-term goal is to develop a device for consumer use, he points out.
Easy-to-use mass product
The three-year Photosens research project, directed by VTT and financed by the EU, ended last January.
– VTT coordinated the project, compiled an international consortium around it, and showed the direction in which the research should go, specifies Pentti Karioja.
– We have established a view of what kind of additional pieces would be needed nationally and at the European level, Jussi Hiltunen continues.
The objective set for the project was to develop a disposable, mass-producible sensor chip for generic multi-parameter sensing applications. A key requirement was that the sensor chip is capable of performing screening tests without specialized equipment or special expertise.
VTT’s contribution to the project was the transfer of nanophotonic structures into polymer structures by the use of UV nanoimprinting and the integration of a multi-parameter sensor.
– Our role was to produce printed intelligence spiced up with optical sensing technology, says Pentti Karioja, summarising the project.
One or multiple substances to be detected
The operating principle of the sensor solution is simple. The sensor platform measures the concentrations of various chemicals in the environment or in industrial process control. When foreign bodies attach on the surface, these can be detected and analysed.
The project used a few examples to demonstrate the functionality of the sensor platform.
– One of them was a pharmaceutical process, in which we measured drug residues. The other was related to the milk scandal in China. The sensor structure developed by us was sensitised to detect melamine, explains Hiltunen.
– A key part of the innovation was the possibility to individualise the substance which the sensor surface would react to, i.e., we can purposely seek for specific agents. In more general terms: we can seek for practically anything. There are millions of possibilities, so we usually carefully define a certain chemical the presence or non-presence of which the sensor will reveal, he continues.
Furthermore, the sensor can identify several agents, not just one. The measures and data of all agents can be collected easily from the same sample.
The sample may also originate from various sources, but the structure of the sensor identifying it is always the same.
Both SERS (Surface Enhanced Roman Scattering) method and photonic crystals are used in the sensor.
First to professional use, then to consumers
The application opportunities for printed intelligence are huge. It facilitates monitoring of, for example, air quality, cleanness of pharmaceutical industry processes and food safety.
– My dream is that, when I’m old, I would have a machine next to my microwave, by which I could make sure that everything is in order. In other words, in the future, this kind of measuring would be available to anyone. They are applicable to monitoring our operations and decision-making concerning, for example, medication and vital functions, Karioja elaborates.
As concerns foodstuffs, they can be used to ensure that they do not contain any additional, harmful agents.
By waving the sensor around in indoor air, we can check whether suspicions of the existence of mould spores turn out to be true or not.
In health monitoring, the daily samples can be taken easily and cost-effectively, transmitted to a physician with a computer, and thus monitor in which direction the indicators telling about our personal health are shifting.
These are just a few examples of the potential applications of the innovation. However, the starting shot has now been fired.
– In the future the chain will go like this: first professional use and only then consumers. The first users can include, for example, local shops and restaurants, because the price of the reader depends on how many of them are needed. The ordinary consumers come only after that, says Pentti Karioja, envisioning the future.
The sensor platform is ready. The measuring methods are ready. The reader developed for analysing the samples is almost ready, only awaiting the final touches.
– We have the functional technology. Now we need to find the companies in the world that are ready to exploit the results of the research and use them in their own operations, summarises Karioja.
Nanocomp involved as a research partner
The company that has made the most advances in the commercialisation of the new innovation is the Joensuu-based Nanocomp Oy, operating in the area of nano-optic manufacturing.
The company participated in the Photosens research project as VTT’s partner and played a vital role in the development of mass manufacturing techniques for sensors.
– Our role was to study the roll-to-roll technology, i.e. how to perform large-volume nanophotonic roll-to-roll manufacturing, says Samuli Siitonen, Chief Technology Officer at Nanocomp Ltd.
In principle, there are three levels in the mass production technology of nanophotonics. Sensors have been produced using traditional lithographic methods for a long time. VTT studied sheet-level technology in particular. Nanocomp focused on the roll-to-roll production level.
– We aim at finding a cost-effective and rapid method for producing sensor chips based on nanophotonics, as well as related techniques and equipment. Our goal is to reach the disposable functioning mode in the component prices, which is what the sensitive measuring method of this sensor structure is all about, says Siitonen.
In a disposable method suited for Everyman, the user of the sample and sensor surfaces would not need to take any complex measures. After use, the sensor could be recycled with plastics or burned.
– In the research project, however, we are discussing very challenging detector types. Ease of use is a future challenge that we keep in mind all the time, says Siitonen.
Any printing press is not suited for printing of sensor chips based on nanophotonics.
– Nanocomp has been working with mass manufacturing of nano-class surface structures for years. Therefore our starting points for developing printing methods of sensor surfaces have been good. We have the equipment for printing optical printed components, or photonic components, and also equipment for their further processing, says Samuli Siitonen.
The sensor is capable of identifying several substances at the same time. In the picture, a single 2x7 chip.
Market launch within the next few years
Even though Nanocomp Ltd has advanced far in its Photosens technology, the sensor structures are not yet in actual production in the company.
– This is largely research aimed at future products. It requires long-term development cycles, specifies Samuli Siitonen.
The technology leader, however, considers the field very inspiring, and the expectations are high.
– Sensor technology production using roll-to-roll method is a very up-and-coming and interesting area of operation. We have been given the opportunity to delve into matters in the forefront. We will be ready the day all support functions for market entry are mature enough, he rejoices.
For example, according to Siitonen, an affordable and easy-to-use reader must be on the market before anyone is interested in buying sensors. Chemical functionalities, which facilitate screening of specific agents, must also be ready.
– This project is not about the launch of a single technology, but a sum of many. Market entry will take place when all the branches are ready. We already have the readiness to make certain types of sensors, but we do not have any off-the-shelf products yet.
Samuli Siitonen believes that concrete steps towards utilising the new innovation will be taken within about five years. Many matters going on right now give strong support for this estimate.