scholarly journals Tetrahydrocannabinol Sensing in Complex Biofluid with Portable Raman Spectrometer Using Diatomaceous SERS Substrates

Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 125 ◽  
Author(s):  
Sivashanmugan ◽  
Zhao ◽  
Wang
Keyword(s):  
Diatomaceous Earth ◽  
Microfluidic Channel ◽  
Principal Component ◽  
Surface Enhanced Raman Spectroscopy ◽  
Forensic Analysis ◽  
Sample Type ◽  
Raman Spectrometer ◽  
Sers Substrates ◽  
Tlc Separation ◽  
Portable Raman

Using thin-layer chromatography in tandem with surface-enhanced Raman spectroscopy (TLC-SERS) and tetrahydrocannabinol (THC) sensing in complex biological fluids is successfully conducted with a portable Raman spectrometer. Both THC and THC metabolites are detected from the biofluid of marijuana-users as biomarkers for identifying cannabis exposure. In this article, ultra-sensitive SERS substrates based on diatomaceous earth integrated with gold nanoparticles (Au NPs) were employed to detect trace levels of cannabis biomarkers in saliva. Strong characteristic THC and THC metabolite SERS peaks at 1601 and 1681 cm−1 were obtained despite the moderate interference of biological molecules native to saliva. Urine samples were also analyzed, but they required TLC separation of THC from the urine sample to eliminate the strong influence of urea and other organic molecules. TLC separation of THC from the urine was performed by porous microfluidic channel devices using diatomaceous earth as the stationary phase. The experimental results showed clear separation between urea and THC, and strong THC SERS characteristic peaks. Principal component analysis (PCA) was used to analyze the SERS spectra collected from various THC samples. The spectra in the principal component space were well clustered for each sample type and share very similar scores in the main principal component (PC1), which can serve as the benchmark for THC sensing from complex SERS spectra. Therefore, we proved that portable Raman spectrometers can enable an on-site sensing capability using diatomaceous SERS substrates to detect THC in real biological solutions. This portable THC sensing technology will play pivotal roles in forensic analysis, medical diagnosis, and public health.

scholarly journals Differentiation of different antifungals with various mechanisms using dynamic surface-enhanced Raman spectroscopy combined with machine learning

2021 ◽  
pp. 2141002
Author(s):  
Hao Li ◽  
Yongbing Cao ◽  
Feng Lu
Keyword(s):  
Machine Learning ◽  
Raman Spectroscopy ◽  
Principal Component ◽  
Surface Enhanced Raman Spectroscopy ◽  
New Drugs ◽  
Dynamic Surface ◽  
Raman Spectrometer ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Portable Raman

With the increase in mortality caused by pathogens worldwide and the subsequent serious drug resistance owing to the abuse of antibiotics, there is an urgent need to develop versatile analytical techniques to address this public issue. Vibrational spectroscopy, such as infrared (IR) or Raman spectroscopy, is a rapid, noninvasive, nondestructive, real-time, low-cost, and user-friendly technique that has recently gained considerable attention. In particular, surface-enhanced Raman spectroscopy (SERS) can provide a highly sensitive readout for bio-detection with ultralow or even trace content. Nevertheless, extra attachment cost, nonaqueous acquisition, and low reproducibility require the conventional SERS (C-SERS) to further optimize the conditions. The emergence of dynamic SERS (D-SERS) sheds light on C-SERS because of the dispensable substrate design, superior enhancement and stability of Raman signals, and solvent protection. The powerful sensitivity enables D-SERS to perform only with a portable Raman spectrometer with moderate spatial resolution and precision. Moreover, the assistance of machine learning methods, such as principal component analysis (PCA), further broadens its research depth through data mining of the information within the spectra. Therefore, in this study, D-SERS, a portable Raman spectrometer, and PCA were used to determine the phenotypic variations of fungal cells Candida albicans (C. albicans) under the influence of different antifungals with various mechanisms, and unknown antifungals were predicted using the established PCA model. We hope that the proposed technique will become a promising candidate for finding and screening new drugs in the future.

scholarly journals Surface-enhanced Raman spectroscopy for the characterization of Vaccinium myrtillus L. bilberries of the Baltic–Nordic regions

2021 ◽  
Author(s):  
Lina Traksele ◽  
Valentinas Snitka
Keyword(s):  
Raman Spectroscopy ◽  
Silver Nanoparticles ◽  
Principal Component ◽  
Surface Enhanced Raman Spectroscopy ◽  
Vaccinium Myrtillus ◽  
Spectral Variation ◽  
Data Set ◽  
Sers Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

AbstractIn this study, an investigation of the wild bilberries (Vaccinium myrtillus L.) of the different Baltic–Nordic regions using surface-enhanced Raman spectroscopy (SERS) combined with principal component analysis (PCA) is presented. The bilberries were collected in Lithuania, Latvia, Finland and Norway. The set of the SERS spectra of the berry extracts (pH ~ 4) were recorded on the silver nanoparticles based SERS substrates. The SERS spectra of the extracts were acquired using 532 nm laser as an excitation source. The morphology of the SERS substrates was evaluated by scanning electron microscopy (SEM) and the presence of the silver nanoparticles was confirmed by the energy-dispersive X-ray spectroscopy (EDX). The enhancement factor (EF) of the silver SERS substrates was found to be 105. It has been shown that a strong fluorescence background, associated with the phenolic compounds found in bilberries, can be subtracted due to the fluorescence-quenching properties of the silver nanoparticles. Therefore, an application of the SERS technique allowed to observe the characteristic peaks of the bilberries and the PCA tool enabled to evaluate the spectral variation across the entire SERS data set. The results presented in this paper show that the SERS technique coupled with PCA chemometric analysis might serve as a complementary method that allows to identify the country of origin of the bilberries based on the spectral differences.

Diethyldithiocarbamate (DDTC) induced formation of positively charged silver nanoparticles for rapid in situ identification of inorganic explosives by surface enhanced Raman spectroscopy

RSC Advances ◽  
2016 ◽  
Vol 6 (57) ◽  
pp. 51823-51829 ◽  
Author(s):  
Juan Chen ◽  
Yu-e Shi ◽  
Min Zhang ◽  
Jinhua Zhan
Keyword(s):  
Raman Spectroscopy ◽  
Silver Nanoparticles ◽  
Surface Enhanced Raman Spectroscopy ◽  
Raman Spectrometer ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Positively Charged ◽  
Portable Raman

Diethyldithiocarbamate could induce the generation of positively charged silver nanoparticles for rapidin situdetection of the explosives with a portable Raman spectrometer.

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