Jason Norman

University of Edinburgh

Chemical sensing with lasing microfluidic droplets of chiral nematic liquid crystals

Following-on from the excellent work from a recent MSc SIS project student, and the summer project of a 1st year CDT PhD student, this PhD proposal seeks to investigate the chemical and biological sensing capabilities of microfluidic droplets of liquid crystal lasers. Chiral nematic liquid crystals can self-assemble into nanoscale helical structures, forming a photonic band-gap, which can be exploited as a self-assembled laser cavities. Such liquid crystal lasers can also be encapsulated into immiscible liquids to form paintable/printable/flowable emulsions of microfluidic lasing droplets. The alignment of liquid crystal molecules at the surface of these droplets is critical to the lasing mechanism, strongly influencing factors such as wavelength, linewidth, threshold, efficiency (intensity), and can even be used to switch lasing mechanisms from photonic band-edge to random lasing, or completely off. Chemical additives within the surrounding fluid can have heavy influence upon surface anchoring properties of the liquid crystal droplets, even at very low concentrations, and thus these droplets have potential for chemical sensing. The wide variety of easily measurable laser performance metrics provide a characteristic fingerprint of the analyte within the microfluidic environment, and provide opportunities for both quantitative and qualitative chemical and biological sensing. The project is mostly experimental in nature, but the 2nd supervisor will provide additional parallel support through computational studies, modelling the complex behaviour of chiral liquid crystal alignment within these confined spheroidal geometries, and helping to predict and optimise sensing behaviours.

William Skinner

University of Edinburgh

Microanalytical platform allowing analysis of 3D tissue cultures for drug discovery

3D cell cultures are emerging as a more physiologically meaningful alternative to monolayer cultures for applications such as drug discovery and drug safety studies. 3D cell structures such as spheroids/organoids are attractive because they develop gradients of oxygen, pH and metabolites that create a microenvironment that is a better mimic of real tissue than monolayer culture – as a result they make better models for drug efficacy and toxicity.

Measuring drug and biomolecule profiles in spheroids is challenging because they contain a relatively small number of cells and are challenging to handle in an automated manner.

In this project we will bring together expertise in engineering to design and build a device, and in biological and analytical chemistry to work with and analyse 3D cell cultures using cutting edge nanosensors and spectroscopic techniques.

The microfluidic device will be used to culture and lyse spheroids allowing in-situ biomolecule and drug extraction. Time-controlled lysis will allow differential extraction of molecules from the outer and inner sections of the spheroid. The molecules will be separated in the device and analysed using high-resolution mass-spectrometry, nmr or Surface Enhanced Raman spectroscopy.

Kostantinos Bantounos

University of Edinburgh

High performance 3D Imaging System using advanced CMOS SPADs

The CMOS Sensors Group within the IMNS at UEDIN has, in collaboration with STMicro, developed CMOS SPAD technology, CMOS SPAD devices and, frequently in collaboration with others, application–specific CMOS SPAD arrays and deployed and characterised them in systems. We have identified short- to medium-range 3D Imaging using CMOS SPADs as a promising yet relatively unexplored application. In this project we plan, in collaboration (possibly with STMicro as a technology collaborator) with a company (yet to be finalised as we are talking to several with different applications in mind) to develop a short- to medium-range 3D Imaging System (3D-IS) for a specific application. The 3D-IS system will use some of the world’s most advanced CMOS SPAD devices recently or soon to be available within the CMOS Sensors Group thus ensuring state of the art performance.

Fiona Moore

University of Edinbugh

Skin-surface Sensing System for Real-time Health Monitoring

There has been considerable activity in recent years to develop non-invasive wearable diagnostic, fitness and lifestyle monitoring technology. While physical measurements, such as heart rate monitoring, have proven successful the next step to biochemical measurement of body analytics has proven to be more difficult. This project aims to develop wearable skin-surface technology mounted in a band or self-adhesive patch that enables continuous monitoring of a range of body analytes. The research will be undertaken in collaboration with nanosensing device manufacturer, Nanoflex Ltd. (www.nanoflex.com).

The medium to be measured will most likely be either sweat or interstitial fluid (ISF). Devices currently being developed tend to rely on measurements undertaken when the wearer is exercising and can be expected to sweat profusely. However, the ability to monitor the constituents of sweat in a subject at rest provides a major challenge, as the volumes of liquid available are very small and occlusive collection methods tend to result in reductions of the localised sweat rate. Very sensitive monitoring technology will be required and Nanoflex, in collaboration with the University of Edinburgh, has developed nanoband electrode array sensing systems that have high sensitivity and excellent immunity to noise and perturbations.

The research will incorporate materials engineering and microfabrication as well as electrical and electrochemical sensing.

Michael Handley

University of Glasgow

CASE Studentship in Computational Imaging for Next Generation Systems.

The last decade has witnessed a revolution in imaging made possible by the development of high-performance electronic detectors and computer processing. The optics within commercial imaging systems have changed little however, but this is about to change. By combining modern optical design and manufacturing with computational image recovery a new class of imaging systems is being developed that enable imaging with capabilities that have not previously been possible; such as imaging with extreme depth of field, the ability to detect range through a single aperture or to form diffraction-limited, wide field-of-view images with very simple optics. The Imaging Concept Group is at the forefront of these developments.

Michael will research new concepts and capabilities in Computational Imaging in collaboration with other PhD students and postdocs within the Imaging Concepts Group. Micheal will collaborate with Optical Designers and Systems Engineers at Qioptiq, St Asaph to develop demonstration systems for possible manufacture by Qioptiq. This will involve inventing, developing and applying new concepts in image science, rigorous optical design of systems, development and application of image-recovery algorithms followed by experimental assessment and testing. The student will spend periods working with Optical Designers and Systems Engineers at Qioptiq in St Asaph. The ideal applicant will have experimental and mathematical-modelling skills combined with an enthusiasm for developing a deep physical and mathematical understanding of optical imaging systems.

Sam Hutchings

University of Edinburgh

High performance 3D imaging system using CMOS SPADS

The CMOS Sensors Group within the IMNS at UEDIN has, in collaboration with STMicro, developed CMOS SPAD technology, CMOS SPAD devices and, frequently in collaboration with others, application–specific CMOS SPAD arrays and deployed and characterised them in systems. We have identified short- to medium-range 3D Imaging using CMOS SPADs as a promising yet relatively unexplored application. In this project we plan, in collaboration (possibly with STMicro as a technology collaborator) with a company (yet to be finalised as we are talking to several with different applications in mind) to develop a short- to medium-range 3D Imaging System (3D-IS) for a specific application. The 3D-IS system will use some of the world’s most advanced CMOS SPAD devices recently or soon to be available within the CMOS Sensors Group thus ensuring state of the art performance.

David Atkins

University of Glasgow

CASE Quantitative Thermal Conduction Measurement and Imaging at 200nm scale

The performance of modern electronic and optical components is dominated by thermal effects. Modern devices make extensive use of nanostructuring to obtain greatly enhanced optical and electronic properties, but this structuring comes at a significant cost since it reduces the ability of the materials used to conduct away heat. Thermal conduction at the nanoscale is significantly different to that observed at macroscopic distances, being subject to acoustic boundary reflection effects, ballistic conduction, phonon-wavelength dependent scattering and quantized thermal conduction. Since the physics of nanoscale thermal transport is so profoundly different it is necessary to develop new techniques for its measurement.

Nanoscale thermal measurements are often made using “Scanning Thermal Microscopy”, a technique related to Atomic Force Microscopy (AFM) in which a thermal sensor is combined with a MEMS AFM sensor to give high resolution measurements of topography and temperature at the same time. This project is concerned with the development and validation of techniques to quantify thermal conduction at the nanoscale using custom AFM probes which have two tips, separated by a few hundred nanometres. The two tips will act as heaters and thermometers, allowing a measurement of the temperature rise from the flow of a known thermal power: Classically this would constitute a measurement of thermal conductivity. Technical objectives are the development of a measurement methodology, determination of the range of validity of the measurement and quantification of errors in measurement with reference to the characteristics of known bulk materials. The project will involve nanofabrication of the advanced sensors in the James Watt Nanofabrication Centre combined with the development of the associated instrumentation and measurement techniques.

Nigel Lucas

University of Edinburgh

Development Characterisation of Nano Electrode Arrays for Electrochemical Sensing.

Scanning electrochemical microscopy (SECM) is used to image the local electrochemical behaviour at interfaces or a substrate surface. Spatially resolved electrochemical signals are acquired by measuring the current at an ultra-microelectrode (UME) tip as a function of precise tip position while scanning the tip over a substrate region of interest. It can be used to probe the surface reactivity of solid-state materials, electrocatalytic materials, enzymes and other biophysical systems. However the serial/scanning nature of the technique can be a serious limitation.

We have developed novel highly-efficient ECM systems based on nanoscale electrode arrays produced using conventional microfabrication techniques [1], [2].

We have recently begun the development of novel non-scanning ECM systems in which each nanoband electrode is underpinned by an individual CMOS amplifier circuit. This is a small scale platform, capable of achieving microscopic electrochemical imaging and competing with conventional SECM.

The current project will advance the previously developed platform by:

1. Increase our understanding of the operation and potential performance of the new devices

2. Test the potential by demonstrating the new technology in one or more specific applications.

3. Advance the maturity of the platform production technology.

Fiona Marquess

University of Edinburgh

Porous metal-organic framework (MOF) materials for chemical sensing: from structural chemistry to device fabrication

Metal-organic frameworks (or MOFs) contain pores the size of molecules. As a consequence, they have shown high selectivity for specific analytes, as only molecules of a certain size and shape can enter the pores (Fig. 1). The uptake of these ‘guest’ molecules can result in quite drastic changes in optical absorption or luminescence at extremely low concentrations of the analyte. These materials therefore have the potential to be used for sensitive and selective detection of liquid and vapour-phase analytes for a range of applications, from chemical weapons detection to medical diagnostics. Recently, we synthesised MOFs containing π-conjugated ligands that result in significant guest-dependent changes in the UV-vis spectra. To date, the mechanism behind the guest-induced changes in spectroscopic behaviour is poorly understood which inhibits the rational design and synthesis of MOFs for specific sensing applications. By using a combination of in-situ X-ray diffraction and optical spectroscopy, we will build on our pioneering in-situ studies of structural changes in MOFs on uptake of specific guest molecules, or in response to application of pressure. This will allow us to optimise the spectroscopic response of MOFs, for targeted sensing of specific analytes in the liquid- and vapour phase, exploiting the pressure-sensitivity of the MOF structure to fine-tune the response

Michael Chung

University of Edinburgh

Wearable electronics for early disease detection from sweat

Early detection of diseases significantly enhances the success for treatment, and can improve the quality of life. Nowadays, smart wearable electronics, such as smart watches or smart clothes, can already assist us with monitoring functions, like heart rate, or measuring glucose levels. The future smart devices will monitor and measure multiple substances that are needed to maintain our health in good quality. This project will develop electronics for early disease detection based on nano- and micro-sized bio-sensors. The sensors design will apply a recently invented method, which describes an ultra-sensitive biosensor based on nanoparticles grown on nanofibers prepared by electrospinning (N. Radacsi and K. P. Giapis, U.S. Provisional Patent No. 62/350,117, 14 June, 2017). Oxygen plasma post-treatment can reduce the amount of the polymer binder, thus improve the electrical properties of the sensor. The prepared sensors will be able to measure in-situ substances in sweat such as electrolytes, pH, lactates etc. A non-invasive, wearable, complex sensor system will be developed for real-life applications. Empa’s Biomimetic Membrane and Textile laboratory has been focusing for a number of years on the field of enhanced scaffolds for tissue engineering, sensing of human body parameters as well as the integration of sensors into e.g. textile structures. Empa is therefore interested in the project as Empa is seeking for cooperation partners in these fields. By collaborating with Scotland’s best scientists on the field, Empa boost its excellence in sensing applications. Empa will pay 70 CHF per calendar day allowance to the PhD student. Furthermore, Empa will pay insurance for occupational accidents. On top of these, Empa will pay for consumables, which will be in the range of 3000 CHF per year. In total, Empa will contribute to the project in the order of 36,000- CHF, which is around £28,000-.