Surface‐enhanced resonance Raman scattering for the sensitive detection of a tuberculosis biomarker in human serum

Abstract

Improvements in the detection of biomarkers indicative of disease continue to be vital to human health. Toward this end, this paper presents (a) the development and characterization of a biomarker detection strategy based on the inherently stronger signals generated by surface‐enhanced resonance Raman scattering (SERRS), as opposed to surface‐enhanced Raman scattering (SERS); (b) the application of this approach to the detection of mannose‐capped lipoarabinomannan (ManLAM), an antigenic marker indicative of active tuberculosis infection; and (c) a comparison of readout for this SERRS platform to that of the more frequently used approach based on SERS. More specifically, the work detailed herein describes the design and testing of a SERRS immunoassay that incorporates a resonance Raman‐enhanced adlayer of cyanine 5 on a smooth gold capture surface and its application to biomarker detection when “turned on” by the tagging of captured ManLAM with gold nanoparticle labels. The results of these experiments demonstrated an improvement in the detection of ManLAM spiked into human serum in terms of limit of detection by 10× and analytical sensitivity of almost 40× when compared with SERS. Findings also indicate that these improvements arise primarily from the intrinsic increase in signal strength due to the resonance Raman effect and a small but measurable increase in nanoparticle label density. Potential routes to further improve the performance of this approach to immunoassay signal generation are briefly discussed.

A Nanoplasmonic Assay of Oligonucleotide‐Cargo Delivery from Cationic Lipoplexes

“…As shown in Figure 2b,c, the arrival of the released Cy5‐ssDNA at the bottom (≈175 nm away from the suspended membrane) of the cavity where the plasmonic hot‐spots reside was readily monitored via the intense SE(R)RS peak of Cy5 @ 560 cm −1 , which corresponds to the polymethine‐bridge stretching mode. [ 35,54 ] From Figure 2a–c, one can observe distinct delivery dynamics among the three lipoplex species. DOTAP/DOPE (Figure 2c) was the most efficient delivery vehicle whereas unsurprisingly, the naked Cy5‐ssDNAdid not permeate the membrane at all.…”

Sensitivity-Improved SERS Detection of Methyltransferase Assisted by Plasmonically Engineered Nanoholes Array and Hybridization Chain Reaction

“…In addition, SERS measurements were performed to further validate the feasibility of the developed strategy. The SERS spectrum of P exhibits the characteristic peaks of Cy5 (curve a of Figure C), including the aromatic ring stretching at 1597, 1367, and 938 cm –1 and the C–C–C stretching of the polymethine bridge at 560 cm –1 . The detailed assignments of the Raman bands of Cy5 are listed in Table S2.…”

“…The SERS spectrum of P exhibits the characteristic peaks of Cy5 (curve a of Figure 4C), including the aromatic ring stretching at 1597, 1367, and 938 cm −1 and the C−C−C stretching of the polymethine bridge at 560 cm −1 . 36 The detailed assignments of the Raman bands of are listed in Table S2. For the P/T duplex, the signal slightly decreases (curve b).…”

Gold nanoparticle-based optical nanosensors for food and health safety monitoring: recent advances and future perspectives

“… 268 In another study, Owens et al chose mannose-capped lipoarabinomannan (ManLAM), an TB antigenic marker, as the target to detect TB. 269 Two kinds of anti-ManLAM antibodies were employed to functionalize the AuNPs and the capture substrate, respectively. Hence, ManLAM antigen would be captured between them.…”