13 June

Photonic biosensing: opportunities and challenges

Thursday 13 June 2019, 12:00pm

ICN2 Seminar Hall, ICN2 Building, UAB

By Prof. Andrew Kirk,  Department of Electrical and Computer Engineering and McGill Institute for Advanced Materials, McGill University, Montreal, Canadá

Abstract: Biomolecular sensors are widely used across a variety of biomedical applications including medical diagnostics, drug screening, environmental monitoring (for example water and food quality testing), and research. Biological function of an affinity sensor requires surface chemistries that support specific capture of the target molecule to be detected. The sensing task then becomes one of measuring the change in surface properties due to molecular interactions; for instance, optical biosensors measure changes in optical properties at the device interface and can be highly sensitive to molecular binding. Whilst various optical sensing technologies have been demonstrated for sensing applications in the biomedical, environmental, and industrial sector, there remains a significant need for improved integration, packaging and signal processing techniques to realise the full potential of the technology. In this talk I will present some of the different approaches that we have taken to implement optical biosensors. The whispering gallery modes of optical microtoroidal resonators have been of interest for biosensing for several years due to their high sensitivity to changes in the local optical environment. We have shown recently that by interrogating these sensors in the time-domain (rather than in the frequency-domain, which is what is more usually done) it is possible to simplify the measurement system while obtaining the same sensing information. Localized surface plasmon resonance (LSPR) in metallic nanoparticles represents another widely used approach to optical biosensing. These structures have the advantage that they can be precisely tailored and can be integrated into very small packages. However they typically have a somewhat broad resonance curve which results in lower sensitivity. I will describe the use of a novel signal processing technique which can significantly improve the limit of detection and signal-to-noise ratio and the structures, and I will also show how data from multiple excitation modes can be optimally combined to yield the maximum information. Finally I will show how the optical absorption properties of gold nanoparticles can be used to achieve an ultrafast polymerase chain reaction (PCR) system.

Hosted by: Prof. Laura M. Lechuga, Nanobiosensors and Bioanalytical Applications Group Leader at ICN2