title: Tobacco-induced alterations to the Fourier-transform infrared spectrum of serum.
abstract: Infrared (IR) spectroscopy can distinguish differences in the characteristics of diverse molecules by using infrared radiation to probe chemical bonds. Consequently, alterations to the molecular characteristics of tissues and body fluids that help define specific pathological processes and conditions can be identified by IR spectroscopy. This study analyzed the molecular spectrum of cotinine by IR spectroscopy and determined tobacco-induced alterations to the IR profile of serum to establish whether these alterations can differentiate smokers and nonsmokers. The IR spectra of serum samples obtained from 20 smokers and 25 nonsmokers were captured using a FTS-40 IR spectrometer. Linear discriminant analysis method was used to partition the samples into smoker and nonsmoker groups according to the discriminatory patterns in the data and into a validation set to test the accuracy of the trained algorithm in distinguishing smokers and nonsmokers. Cotinine molecules were shown to exhibit a characteristic IR absorption spectrum. Several differences in the sera spectra of the two groups were observed, including an overall shift in the secondary structure of serum proteins favoring increased beta-sheet content in smokers. The overall accuracy of the training and validation sets was 96.7%, and 82.8%, respectively. The identification of specific absorption peaks for tobacco-induced alterations to the IR molecular profile of serum permits the development of an IR spectroscopy technique that can be used to differentiate smokers from nonsmokers. This further extends the utility of IR spectroscopy as a rapidly emerging tool in the field of molecular biodiagnostics.
authors.affiliation: Department of Oral Biology, Faculty of Dentistry, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, MB, R3E 0W2, Canada.
authors.forename: J T
authors.initials: JT
authors.lastname: Borden
authors.forename: A
authors.initials: A
authors.lastname: Man
authors.forename: D A
authors.initials: DA
authors.lastname: Scott
authors.forename: K-Z
authors.initials: KZ
authors.lastname: Liu
mesh_terms: D000328:Adult; D002849:Chromatography, Gas; D003367:Cotinine / Q000097:blood* / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D009538:Nicotine / Q000097:blood / Q000378:metabolism; D012907:Smoking / Q000097:blood*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods* / Q000592:standards; D015813:Substance Abuse Detection / Q000379:methods* / Q000592:standards; D014029:Tobacco Use Disorder / Q000175:diagnosis*
chemical_list: D009538:Nicotine; D003367:Cotinine