Integrated compound semiconductor lab-on-chip optical biosensor

The diagnosis of infectious diseases currently relies on a variety of laboratory-based tests, e.g. culture, immunoassays and microscopy, which have various limitations. The common shortcoming is that those approaches require the transport of biological samples to be analysed from the point-of-care to a laboratory equipped with expensive instrumentation where experienced personnel perform costly and time-consuming tests. For many infectious diseases, a timely diagnosis at the point-of-care level resulting in a rapid initiation of the treatment can be critical.

This project will be embedded within an on-going ambitious research programme aimed at the development of a novel optical biosensor device which surpasses current technologies. The biosensor will combine multiplex capabilities, detecting hundreds of biomarkers at once, with quantitative real-time detection, miniaturisation, low-cost and user-friendliness, while exhibiting high sensitivity and specificity, representing a 'game-changer' in the biosensors market.

The device design is based on a novel lab-on-a-chip approach, where the optical excitation, sensing elements, and detectors are fabricated on the same semiconductor chip. The building blocks of the sensor are photonic crystals, i.e. optical devices where periodic structures of dielectric materials are engineered to tailor the interaction with light, to create unique optical properties.

Project aims and methods

The main objectives of the project are:

1) Design of the device: The student will have access to a multi-physics modelling software (COMSOL), which will be used to simulate the optical, electronic, and thermal properties of the device components to optimise their performance. The device will be subsequently fabricated according to the design, by using state-of-the-art lithography and etching techniques.
2) Characterisation of the device components: The student will characterise the electrical and optical properties of the different components of the fabricated device and will compare them with the simulations, providing feedback for the design/fabrication steps. This step will also be a first demonstration of the device performance in multi-biomarker sensing