Towards quantitative point of care detection using SERS lateral flow immunoassays

Abstract

The rapid detection of biomolecules in a point of care (POC) setting is very important for diagnostic purposes. A platform which can provide this, whilst still being low cost and simple to use, is paper-based lateral flow immunoassays (LFIA). LFIA combine immunology and chromatography to detect a target by forming an immunocomplex with a label which traps them in a test zone. Qualitative analysis can be performed using the naked eye whilst quantitative analysis takes place by measuring the optical signal provided by the label at the test zone. There are numerous detection methods available; however, many suffer from low sensitivity and lack of multiplexing capabilities or are poor at providing POC quantitative analysis. An attractive method to overcome this is to use nanoparticles coated in Raman reporters as the labelled species and to analyse test zones using surface-enhanced Raman scattering (SERS). Due to the wide variety of metal nanoparticles, Raman reporter and laser excitations that are available, SERS-based LFIA have been adapted to identify and quantify multiple targets at once. Large Raman microscopes combined with long mapping times have limited the platform to the lab; however, by transferring the analysis to portable Raman instruments, rapid and quantitative measurements can be taken at the POC without any loss in sensitivity. Portable or handheld SERS-LFIA platforms can therefore be used anywhere, from modern clinics to remote and resource-poor settings. This review will present an overview of SERS-based LFIA platforms and the major recent advancements in multiplexing and portable and handheld detection with an outlook on the future of the platform. Graphical abstract

Label-Free Saliva Test for Rapid Detection of Coronavirus Using Nanosensor-Enabled SERS

“…Hence, a standardized testing protocol should be developed for the assay. Further, the SERS system should distinguish between various viruses and other microbial species such as SARS-CoV-2, MERS, Influenza A, Adenovirus, and parainfluenza virus before deploying for clinical applications [ 44 , 45 ]. This study demonstrates the ability to distinguish between four closely related viral species; however, the number is much higher.…”

Nano-biosensor for SARS-CoV-2/COVID-19 detection: methods, mechanism and interface design

“…The SERS-LFIA method is a good candidate for diagnosing COVID-19 through strong, specic, and stable SERS signals. [90][91][92][93][94] In a study by Haifeng Liu, 84 the SARS-CoV-2 IgM/IgG antibodies in clinical samples were analyzed through a SERS-LFIA in 25 minutes (Fig. 3a-c).…”

Point-of-care electrochemical testing of biomarkers involved in inflammatory and inflammatory-associated medical conditions

“…Recently published POCT electrochemical devices for the detection of COVID19-related diagnostic markers were analyzed and the most important characteristic and figures of merit are summarized in Table 5 . For more exhaustive research on COVID19-associated diagnosis tools reporting other detection mechanisms, besides the electrochemical ones, several recent reviews are recommended[ 121 – 126 ].…”