Development of Point of Use Bionanosensors for Liver Injury

This research involves the development of innovative bionanosensors combined with handheld Raman instrumentation that can be deployed at the point of care. The developed bionanosensors will have superior performance in terms of sensitivity, ability to quantify biomarkers and multiplexing capabilities compared to existing technologies. The project will focus on the development of low cost, disposable, point of use sensors and their integration, in terms of sampling and readout, with portable Raman instruments.
The proposed approach involves developing a surface-enhanced Raman scattering (SERS)-based lateral flow immunoassay (LFIA) diagnostic test for the detection of liver injury at the point of care. This test will use clinical samples, such as a finger-prick of blood, applied directly to the device to produce a quantifiable response of the liver injury biomarkers. The concept takes advantage of affordable, paper-based devices where the blood sample can be applied directly, allowing for the separation of red blood cells upon application. Detection will be achieved using biorecognition molecule-functionalised gold nanoparticles, which our previous work has shown to be effective in terms of flow capabilities and functionalisation. Gold nanoparticles are optically bright and visible to the naked eye, but greater sensitivity and quantification can be achieved using SERS. This increased sensitivity is crucial for detecting the low biomarker levels required in clinical samples. SERS provides distinct, narrow spectral peaks for different analytes, enabling simultaneous detection and the identification of multiple biomarkers in a single measurement.
Our interest lies in detecting biomarkers related to acute liver failure (ALF) and collaborating on clinical research to identify biomarkers indicative of drug-induced liver injury (DILI). If not detected rapidly, DILI poses a significant mortality risk, with paracetamol overdose being the leading cause. Despite its availability for minor ailments, around 40% of self-harm patients in the UK ingest paracetamol in overdose, leading to approximately 100k hospital presentations annually. Therefore, we propose developing a multiplexed SERS-LFIA to detect the DILI biomarkers alanine transaminase (ALT) and aspartate transaminase (AST) for efficient patient stratification. Using a handheld Raman spectrometer for interrogation of the SERS-LFIA device, developed in collaboration with industry partner Wasatch Photonics, the test will generate accurate measurements to identify liver injury by calculating the AST:ALT ratio from a single test.

The initial focus will be on the development of a lateral flow assay for the detection of ALT and AST separately in serum and blood. The output from the test lines will be analysed using the handheld Raman instrument and the SERS signal related to the concentration of ALT and AST.

The assays will then be combined into one platform, to produce a multiplexed lateral flow assay that will initially identify and quantify the presence of both ALT and AST from a single serum or blood sample. The multiplexed output signal generated needs to be interpreted such that the unequivocal detection of each analyte is made and/or the concentration predicted giving a response using an easily interpretable interface. The multiplexing capability will then be further expanded to other biomarkers.

The integration of the lateral flow assay to the handheld Raman instrumentation will be developed to increase the reproducibility and sensitivity of the measurements. With Wasatch Photonics, we will investigate different detection approaches to maximize the data capture and ensure a simple interface is developed for use in a clinical setting.

We will then carry out field testing of the assay using real clinical samples. This will allow us to factor in matric effects for real samples as well as the practicalities of sampling and detection within different environments