Rapid, Quantitative, and Ultrasensitive Point‐of‐Care Testing: A Portable SERS Reader for Lateral Flow Assays in Clinical Chemistry

Abstract

The design of a portable Raman/SERS‐LFA reader with line illumination using a custom‐made fiber optic probe for rapid, quantitative, and ultrasensitive point‐of‐care testing (POCT) is presented. The pregnancy hormone human chorionic gonadotropin (hCG) is detectable in clinical samples within only 2–5 s down to approximately 1.6 mIU mL −1 . This acquisition time is several orders of magnitude shorter than those of existing approaches requiring expensive Raman instrumentation, and the method is 15‐times more sensitive than a commercially available lateral flow assay (LFA) as the gold standard. The SERS‐LFA technology paves the way for affordable, quantitative, and ultrasensitive POCT with multiplexing potential in real‐world applications, ranging from clinical chemistry to food and environmental analysis as well as drug and biowarfare agent testing.

Surface‐enhanced Raman spectroscopy for on‐site analysis: A review of recent developments

“…(c) Photograph of the powerful (up to 450 mW) yet compact 785 nm diode laser. (Adapted from Tran et al (2019) [59] with permission from Wiley.) very suitable for on-site inspection because of its portability.…”

“…These parts directly determine the performance of a portable Raman spectrometer and the potential application of the instruments (Figure 3). [59][60][61][62] With the development of various new technologies, portable Raman spectrometers will become smaller and smaller, with higher resolution, more comprehensive performance, and lower prices.…”

Recent Advancement in the Surface-Enhanced Raman Spectroscopy-Based Biosensors for Infectious Disease Diagnosis

“…Among many different approaches, microfluidic devices, lateral-flow assays, and lab-on-a-chip assays are the most common diagnostic assay platforms that have been developed and tested for infectious diseases [94,[115][116][117][118][119][120]. SERS-based assays have been integrated into these devices to be used for both qualitative and quantitative biomarker detection [7,8,70,73,91,94,[121][122][123][124]. Integration of SERS detection schemes into lateral flow assays are commonly seen in the recent work related to infectious disease diagnosis [91,122].…”

“…Among new detection modalities, surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful analytical technique for molecular analysis, which can be particularly advantageous for diagnostic purposes when the Raman spectroscopy is combined with inherent optical and chemical properties of plasmonic nanoparticles [4][5][6][7][8][9][10][11][12][13]. SERS is the main method of enhancing the inherently weak Raman intensity, such that Raman scattering can be widely utilized in analytical applications.…”

“…In general, SERS-based sensing approaches have become more attractive and advantageous over conventional methods such as fluorescence due to ultra-sensitivity, even up to single-molecule detection, rich spectroscopic information provided on the molecular structure of interest that enable direct biomarker detection, and higher multiplexing capability [8,34,[60][61][62][63][64][65][66][67][68][69][70]. Among these advantages, the multiplexed SERS detection, in particular, is very attractive in clinical settings as it allows for the detection of a panel of biomarkers ensuring higher confidence in the diagnosis and poses as a better alternative to the commonly used fluorescence-based multiplexed biosensing.…”