Laser Direct Write (LDW) is one of the most versatile direct-write techniques, which uniquely enable adding, removal and modifying target materials without any physical contact. Additionally, it is able to process complex materials with a resolution spanning more than three orders of magnitude, from millimetres to microns, which makes LDW process a unique technique to fabricate structures that are not possible using other techniques.
One of the unique features that the LDW technique provides is that it allows processing and modifying of a wide range of materials for fabrication of devices and structures within a research laboratory environment or even as an entire manufacturing system on the factory floor.
The key components of a LDW system normally consist of three parts: the laser source, beam delivery pathway and substrate translation system. The heart of any LDW process is always the laser source. A wide range of lasers, from ultrafast pulsed systems to continuous-wave (c.w.) systems, can be applied during the LDW process as befits different applications.
To date, many kinds of LDW systems have been used in science and engineering, and they can be classified into three main categories: LDW subtraction, where material is removed; LDW addition, where material is added; and finally LDW modification, where material is modified. The technique we have developed belongs to the last category (LDW modification), namely using the LDW procedure to modify the material in the substrate in order to form designed patterns based on light-induced photo-polymerisation.
In our work, a new approach towards the fabrication of paper-based POC diagnostic sensors is proposed, which is a simple laser-based direct-write (LDW) procedure that uses polymerisation of a photopolymer to produce the required fluidic channels in porous substrates. Furthermore, this LDW technique is also further developed and explored for introduction of a range of additional functionalities in paper-based microfluidic devices.
Supervisor: Dr C L Sones
The focus of our group’s research is the development of user-friendly sensors or devices for affordable and rapid clinical diagnostic testing at the point-of-care of a patient, i.e., at their hospital bedside or in a care/nursing home, in ambulance or at home.
The broader aim of the projects below is to use a laser-based direct-writing technique developed and patented by our group to pattern microfluidic devices in paper for the creation of the diagnostic sensors or tests.
To detail, the innovative laser-based manufacturing technique is used to define/create within a paper substrate, custom-designed fluid flow paths that when used in combination with adapted/modified bio-chemical assays provides a route to sensing the targeted analyte, but with much desired functionalities such as multiplexing, semi-quantitation and enhanced sensitivity.
This research is highly multi-disciplinary, which not only draws upon expertise in laser physics/engineering and microfluidics, but also vital knowledge of biochemistry and medicine.
PhD Project 1: The objective is the development of lateral flow tests (such as those widely used during the COVID-19 pandemic) for simultaneous detection of multiple disease-specific biomarkers which help early-stage detection of the targeted diseases or conditions – examples of these include tuberculosis (TB, a disease which according to the WHO Global TB Report–2015, ranks alongside HIV as a leading cause of death worldwide), sepsis, allergy and asthma. Each of these are individual projects for which research will happen in collaboration with clinical researchers from either a different department or institute.
PhD Project 2: The objective of this project is the development of point-of-care diagnostics tests which allow the detection of bacterial pathogens that routinely cause infections such as upper respiratory tract infections and urinary tract infections. The goal is to develop devices that are uniquely designed to simultaneously identify both a bacterial pathogen and its susceptibility to different antibiotics - an important pre-requisite that provides an essential guide to a GP/Consultant in prescribing the correct antibiotic required for the treatment of that specific bacterial infection. To further reduce the time-to-result, we have explored the use of AI-algorithms, and this project will further that methodology.
The projects are mainly experimentally oriented and will provide multiple opportunities to train across disciplines through working within laboratories (laser- and bio-labs with different systems/instrumentation and procedures) at different locations (universities, central governmental labs or hospitals) within UK and outside. It will also provide valuable learning opportunities relating to impact awareness and outreach to lay audience.
We are seeking to enrol individuals who are enthusiastic not only about learning across the diversely different disciplines/subjects but also about contributing as an effective team player through their relevant subject knowledge or experience.