A PHOTONIC BIOSENSOR FOR SPACE APPLICATIONS ( PBSA )

Introduction: PBSA Project (http://www.pbsafp7.eu) addresses the topic of the EU Framework Programme 7: Bringing terrestrial SME research into the space domain [1]. The project focuses on the development of photonic‐based biosensor technology [2] for biochemical applications into the space domain. Two main fields of application have been identified: biomonitoring human spatial installations, such as space stations or potential planetary human settlements, and astrobiology, in the context of planetary exploration. The biosensor has been designed to meet the requirements arising from such applications, in terms of sensitivity, resilience, dimensioning and performance. There are a number of applications in space that require rapid, robust, light and automatic biosensing techniques. For example, for checking the microbial contamination in space stations or searching for life in planetary exploration. The PBSA instrument implements a Lab-on-a-chip (LoC) device with a photonic immunosensor and demonstrates its use for microbial monitoring and biomarker detection. PBSA uses recent advances in antibody microarray-based immunosensors with two powerful technologies, photonic integrated circuits (PICs) and microfluidics. System Description: Basically three main building blocks can be distinguished in the PBSA Biosensor: the photonic integrated circuit (PIC) (Figures 1 and 2), the biomolecular probes (in this case antibodies), and the microfluidic subsystem (Figure 3). They are set up in a 115x115x130 mm box, which also includes the control electronics (Figure 3). The principle of the photonic measurement is shown is Figure 1: Silicon nitride rings and waveguide are printed onto silicon; a laser bean enter by one side of the guide; the microrings are functionalized with a bioreceptor molecule such as the antibodies; after injection of the sample, the target molecules (red rhombs) or analytes, bind to the capturing antibodies and this induces a shift in the optical signal (it resonates) which is proportional to the concentration of the analyte; the biosensor is regenerated by washing with a regeneration buffer, usually a strong base (diluted NaOH) or acid solution (glycine at pH 2.3). The use of PICs enables the implementation of highly integrated solutions into a Lab-on-a-Chip. Multiple detection probes can be integrated into a single chip (Figure 2). The PIC based solution permits realtime measurement of the target analytes, leading to savings in the complexity of the detection protocols and reliability.