SERS multiplexing of methylxanthine drug isomers via host–guest size matching and machine learning

Abstract

Multiplexed detection and quantification of structurally similar drug molecules, methylxanthine MeX, incl. theobromine TBR, theophylline TPH and caffeine CAF, have been demonstrated via solution-based surface-enhanced Raman spectroscopy (SERS), achieving highly...

SERS biosensors based on cucurbituril-mediated nanoaggregates for wastewater-based epidemiology

“…Similarly, CB-Au NP SERS sensors can detect drug molecules theophylline (TPH) and theobromine (TBR), which are metabolites of caffeine, down to ~9 ng mL -1 (50 nM) with highly reproducible signals. 35 The detection limit of MeX using CB-Au NP nanocomposites is an order of magnitude better than similar SERS techniques. The SERS sensors allow real-time quantification as opposed to conventional technique such as HPLC.…”

“…Hence, detecting multiple analytes in the same measurement run offers practical advantages such as high throughput sample preparation and measurement, as well as consistent data set from the same sample. The CB-Au NP SERS systems allow multiplexed quantification of target analytes with highly reproducible signals, which are essential to reliable machine learning models, via formation of host-guest complexes and precise plasmonic hotspots, as evidenced by the recent examples of SERS detection of neurotransmitters 40 , methylxanthines (MeX) 35 , nucleobases 41 and nitroexplosives 12 .…”

“…Notably, multiplexed quantification of MeX drug isomers, TPH and TBR, has also been demonstrated with the CB8-Au NP SERS sensors at sub-μM levels. 35 The dynamic range of the sensors can be extended by using machine learning algorithms, which is particularly useful for quantifying multiple analytes in complex matrix such as wastewater. Meanwhile, DNT can be detected in the presence of model organic contaminants such as 4-mercaptobenezoic acid and 4-mercaptophenylboronic acid which bind strongly to Au NPs, implying the potential of the CB-Au NP SERS sensors towards detecting multiple target analytes in environmental monitoring.…”

Multi-mode enhanced Raman scattering spectroscopy using aggregation-free hybrid metal/metal-oxide nanoparticles with intrinsic oxygen vacancies

“…22,25 The hybrid SERS and PIERS spectra show strong correlation, following approximately a power law between intensity and concentration range for all DNT peaks (R 2 between 0.9 and 0.99, Figure 4b, S23). 50 The DNT peaks at 889 cm -1 and 1289 cm -1 were not easily visible in the plain SERS spectra, however, with an FFT filter applied to filter out background noise (Figure S25), the 1359 cm -1 peak shows a good correlation with a power law between the intensity and the concentration (R 2 = 0.94) (Figure 4b). For 50 μM DNT, using equation 2, the 1359 cm -1 peaks exhibit a 16 times hybrid SERS enhancement, and a 22 times PIERS enhancement.…”

Part-Per-Billion Level Chemical Sensing with a Gold-Based SERS-Active Substrate

“…In this study, the drug caffeine was selected as a probe molecule to evaluate this sensor, as it generates a strong SERS response at 785 nm. The SERS of caffeine has been reported for various substrates, mostly silver colloids in water, in extracts from tea and coffee, and in biofluids [24][25][26][27][28][29][30][31][32][33][34][35]. Caffeine SERS has been measured and reported at 1 ppb on silver colloids [24] and 100 ppm on gold colloids [28].…”