Silicon-based photonic biosensors integrated into a semiconductor chip technology can lead to major advances in point-of-care applications, food diagnostics, and environmental monitoring through the rapid and precise analysis of various substances. In recent years, there has been an increasing interest in sensors based on photonic integrated circuits (PIC) because they give rise to cost effective, scalable and reliable on-chip biosensors for a broad market. The silicon-on-insulator (SOI)-technology is the most attractive technology for PICs from commercial point of view since it provides a scalable platform for mass production and the opportunity for monolithic integration of electronic and photonic devices, which is known as electronic photonic integrated circuits (EPIC). This allows the integration of sensors, detectors and read-out electronics in a single chip.
Once the photonic chip is fabricated, the silicon surface of the sensor can be coated with a covalently attached sensing layer. This layer determines the specific detection and, hence, the application. This step, however, is independent from the fabrication of the chip, making the PIC and EPIC technology attractive for both, science and industry. A further advantage of PICbased biosensors is the possibility to realise sensor arrays. This allows for the detection of several substances in parallel (multiplexing).
During the last two decades, integrated photonic sensors have been intensively studied in terms of sensitivity and reliability. However, the bottle-neck for a transfer from laboratory to industry is the position of the sensing area, since it adjoins optical and electronical components. This prohibits a full packaging and makes the sensor handling impractical.
To tackle this general problem, the project BioPIC develops a novel integration approach to separate the sensing area from the rest of the chip. The project idea is to shift the sensor from the crowded and water-sensitive front-side of the chip to the back-side.
For the first time, this gives prospective to a fully packaged, cost-effective photonic sensor platform; ready to use for scientists as well as industrial partners in Europe. This technology is intended to create a “large scale effect”, because it enables the development of numerous applications in healthcare, food analysis as well as environmental monitoring, which is expected to improve our life quality and gives special benefit to European citizens and civil society in general. Since it has an extremely broad application spectrum it is further expected to trigger innovative start-ups in Europe and to create jobs in different disciplines.
As proof-of-principle, the project BioPIC aims to demonstrate the fast detection of cardiac troponin. Cardiac troponins are proteins released into the blood after a heart attack. Here, the envisioned industrial application is a point-of-care sensor for emergency rooms and family doctors.