Laser-based fabrication of medical diagnostic devices in paper

Introductory background to the work

Laser Direct Write (LDW) is one of the most versatile direct-write techniques, which can uniquely enable addition, removal and modification of target materials via a non-contact mode. Additionally, such techniques are able to process a range of different complex materials with resolutions spanning more than three orders of magnitude, from millimetres to microns, which make LDW processes appealing for the fabrication of uniquely-shaped structures that are not possible using other techniques.
Another the distinctive 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 both a research-based laboratory environment or even within a manufacturing system on the factory floor.
A LDW technique normally consists of three key components: the laser source, a beam delivery pathway and a substrate translation system. The heart of any LDW process however is the laser source. A wide range of lasers, from ultrafast pulsed systems to continuous-wave (c.w.) systems, can be applied for LDW processing depending on the application.
To date, many kinds of LDW techniques have been used in science and engineering, and they can be classified into three main categories: LDW subtraction techniques, where material is removed; LDW addition techniques, where material is added; and finally LDW modification techniques, where material is modified. The technique we have developed belongs to the last category (LDW modification), wherein, the LDW procedure is used to modify the material in order to form designed patterns within in, and is based on the principle of light-induced photo-polymerisation.
Our research in based around the use of this technique for the fabrication of paper-based POC medical diagnostic sensors via the polymerisation of a photopolymer impregnated into the porous paper substrate to produce the required lab-on-chip type fluidic devices in the porous substrates. Furthermore, we have also been exploring the use of modified forms of this technique to introduce of a range of additional functionalities in such paper-based microfluidic devices.
Over the last two and a half years we have been funded by the U.K. scientific funding body, EPSRC, via two grants totalling ~ 1.2m to explore this work, and have filed four patents to cover various aspects of this novel laser-writing method. Furthermore, more recently, we have also received funding from our university based Network for Antimicrobial Resistance and Infection Prevention (NAMRIP) in the form of a pump-priming award to explore the use of such laser-patterned paper-platforms for creation of devices that combat the global threat of anti-microbial resistance. We have also validated the commercial applicability of our laser-based method through a market research exercise funded by Innovate UK, and hence are in the process of starting our own spin-off company to exploit the huge potential of our current research.


Project - Laser-based fabrication of medical diagnostic devices in paper

The broader theme of our research activity is the development of ‘affordable and user-friendly’ medical diagnostic devices that allows either the patients themselves or an untrained personnel, or a healthcare professional such as nurse or a doctor to test for medical conditions or diseases from the patient’s bed-side i.e., at the point-of-care of the patient. Such fluidics-based devices can provide results fairly rapidly without unwanted time-delays, and hence can serve as early-screening tools that help the doctor promptly decide on a treatment plan for the patient.
To make such ‘low-cost and rapid’ diagnostic tests we are exploring the use of a novel, proprietary laser-based method for creating fluidic patterns such as flow-channels and flow-reservoirs in an extremely cheap and ubiquitous material – paper and other commercially available porous materials such as fabrics.
The strategy is to employ these innovative fluid-flow patterns in conjunction with adapted/modified bio-chemical reactions/assays to produce simple lateral-flow-type products such as pregnancy dip-sticks which can be currently bought off the shelf in a supermarket.
The targeted application for this project is early-stage detection of tuberculosis, a disease which has been identified as a major threat to mankind, and we believe that our project will make a significant impact on the medical diagnostics industry. The project is mainly experimentally oriented, but there will be opportunities for theoretical simulations.