Portable and multiplexed lateral flow immunoassay reader based on SERS for highly sensitive point-of-care testing

Rapid ultra-sensitive diagnosis of clostridium difficile infection using a SERS-based lateral flow assay

“…45 Each SERS nanotag was mixed with its corresponding target for 5 minutes to enable the selective capture of the analytes forming immuno-complexes. 30 Each biomarker's LF strips were then dipped into the assigned immuno-complex solutions in the 96 well-plate for 10 minutes to allow the solutions to migrate upward by capillary force. This led to formation and accumulation of sandwich complexes on the test lines due to the presence of pre-immobilised capture antibodies.…”

“…The control lines remained colored for all concentrations, indicating that the LF strips were working correctly. 30 The LF strips were then washed out with 0.01 M Tris buffer (pH 8.4) for 5 minutes to remove the excess immuno-complex solutions from the strips surface to avoid the Raman background signal that can interfere with the test lines scan. This enabled highly sensitive quantitative detection for both biomarkers test lines using a handheld Raman spectrometer to acquire their SERS signals in 0.5 s. Each test line was scanned in orbital raster scanning (ORS) mode to acquire the average SERS signal from test line zones and to reduce the SERS signal variability between repeated scans.…”

“…59 Moreover, the readout time of the test lines using a handheld Raman spectrometer in ORS mode is much faster than the lengthy mapping scan of the test lines using the benchtop Raman microscopes which require scanning hundreds to thousands of pixels. Accordingly, this paves the way towards an accurate, early and rapid clinical diagnosis of CDI at the POC and in hospitals wards, 27,30,31,60 which will greatly assist in implementing the best treatment protocol and infectious disease control measures in a timely manner. ToxB in a larger scale study of clinical specimens to further investigate its capacity to be a potential alternative diagnostic test for CDI.…”

“…In addition, the use of a handheld Raman spectrometer with this novel duplex LFA, paves the way to move the C. diff diagnostic test from localised laboratories to POC application. [30][31][32] This would allow hospital staff to implement infectious disease control measures in a timely manner, which could lead to more cost-effective systems. 33…”

Point-of-Care Diagnoses and Assays Based on Lateral Flow Test

“…Development of coloration readers suitable for standard LFT is a way of how to improve the assay. e reader devices are especially desired in pointof-care testing [66]. e improved LFT assays are quantitative or at least semiquantitative with acceptable accuracy of concentration range determination.…”