Point of care detection of multiple biomolecules using a SERS lateral flow assay

This project aims to develop a novel lateral flow assay (LFA) paired with surface enhanced Raman scattering (SERS) for the quantitative detection of multiple biomolecules simultaneously. LFAs offer a rapid, low-cost and user-friendly approach for the detection and diagnosis of disease; however, they lack in sensitivity due to naked eye detection and are not suitable for quantitation.

To overcome these disadvantages, alternative detection techniques, such as SERS, can be combined with LFAs. SERS is a spectroscopic technique where distinct spectra can be obtained from analytes and significant enhancement of signal is afforded through the use of metal nanoparticles, such as silver or gold colloid. Since gold nanoparticles (AuNPs) are already used in LFAs for antibody binding and to provide the desired colour change, these can be easily tagged with a Raman reporter molecule to introduce SERS capabilities.

SERS improves the sensitivity of LFAs by allowing detection below the visual limits and introduces quantification capabilities as the signal obtained is proportional to the amount of analyte present in a sample. Additionally, SERS allows the detection of multiple targets simultaneously as separate reporter molecules can be selected for different biological targets and distinct Raman spectra can be obtained for each.

Therefore, the combination of SERS with LFAs allows the low-cost, rapid and user-friendly detection platform to be more sensitive, quantitative and suitable for multiplexed detection.

SERS-based lateral flow assays have recently been developed to detect single biomolecule targets, where the biomarker is generally a protein. However, in this project the aim is to develop an assay that can target multiple biomolecules, i.e. protein and miRNA, simultaneously, thus providing a more in-depth understanding of disease states. Ultimately, the goal is to develop a device that can be used at point-of-care (POC) to quantify levels of multiple class of biomarker that have been identified as indicators of various diseases.

The specific interactions of each class of biomolecule will be studied, such that dynamic range and detection limits can be optimised for each biomarker. Additionally, the assay will be investigated in biological matrices as the end goal will be to detect multiple biomarkers from blood samples. The ability to quantitatively detect low levels of various biomolecules on a single device from a blood sample would be a significant step in patient care.