Rapid Analysis of Cocaine in Saliva by Surface-Enhanced Raman Spectroscopy

Abstract

Increases in illicit drug use and the number of emergency-room visits attributable to drug misuse or abuse highlight the need for an efficient, reliable method to detect drugs in patients in order to provide rapid and appropriate care. A surface-enhanced Raman spectroscopy (SERS)-based method was successfully developed to rapidly measure cocaine in saliva at clinical concentrations, as low as 25 ng/mL. Pretreatment steps comprising chemical separation, physical separation, and solid-phase extraction were investigated to recover the analyte drug from the saliva matrix. Samples were analyzed using Fourier-transform (FT) and dispersive Raman systems, and statistical analysis of the results shows that the method is both reliable and accurate, and could be used to quantify unknown samples. The procedure requires minimal space and equipment and can be completed in less than 16 minutes. Finally, due to the inclusion of a buffer solution and the use of multiple robust pretreatment steps, with minimal further development this method could also be applied to other drugs of interest.

Sources of variability in SERS spectra of bacteria: comprehensive analysis of interactions between selected bacteria and plasmonic nanostructures

“…The power of SERS lies also in its ability to identify chemical species in a very fast way. It can be used to detect and identify pigments [ 2 ], poisons [ 3 ], narcotic substances [ 4 – 6 ], and materials of biological origin [ 7 – 10 ]. It is also applied in examination of single molecules [ 11 , 12 ] and in identification of structures more complicated than chemical compounds, namely viruses [ 13 , 14 ], fungi [ 15 ], cancer cells [ 16 – 18 ], and bacteria [ 19 – 21 ].…”

Review of SERS Substrates for Chemical Sensing

“…Real-Time Analyzers also offer Ag or Au sol gel substrates in capillary tubes and on 96 well microplates. Cocaine detection in saliva using the Ag and Au sol gel capillary tubes has been demonstrated [38]. …”

“…These include benzene, toluene, ethylbenzene, and xylenes (BTEX) [2,3,4,5]; polycyclic aromatic hydrocarbons (PAHs) [6,7,8,9]; volatile organic compounds (VOCs) such as chlorinated solvents [3,10] and methyl t-butyl ether (MTBE) [3]; heavy metals [11,12,13,14,15]; toxic or radioactive cations/anions [16,17,18,19,20,21,22,23,24]; ionic nutrients [16,25,26,27]; pesticides [28,29,30,31,32]; drugs and pharmaceuticals [33,34,35,36,37,38]; and explosive materials [39,40,41,42,43]. In addition, SERS has been combined with other analytical techniques such as gas chromatography (GC) [44,45], thin layer chromatography (TLC) [46], liquid chromatography (LC) and flow injection analysis (FIA) [47,48,49], and electrochemistry [50,51].…”

Semi-automated Biopanning of Bacterial Display Libraries for Peptide Affinity Reagent Discovery and Analysis of Resulting Isolates

“…Biopanning is a proven technique for affinity reagent discovery, with bacterial display libraries a convenient source for peptide affinity reagents 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 . Similarly to phage display 25 26 and yeast display 27 28 , the peptides are exposed on the cell surface and are available to bind to both biotic and abiotic targets, with these interactions driven by both the peptide backbone and the unique properties of the amino acid side-chains 29 .…”

“…Recently, biopanning bacterial display libraries has become even more straightforward and reliable with the use of semi-automated magnetic-activated cell sorting (MACS or MCS) methods 9 14 39 . These methods have been demonstrated for biological targets using several similar sorting platforms with different advantages, including a commercially available automated magnetic-activated cell sorting (autoMACS or autoMCS) instrument (see table of materials) 1 14 15 and more specialized devices which enclose the sample in a disposable cartridge 7 9 or chip 39 , a valuable specification for use with organisms or toxins that are Biosafety Level 2 (BSL-2) or higher 7 . These semi-automated methods could be extended to sort for peptides able to bind to abiotic materials if the materials are magnetic or have the ability to be coated onto a magnetic bead, and for use with different organisms (such as anaerobic bacteria) if the sorting and growth conditions are altered.…”