Objectives To compare the sialic acid (SA) levels in saliva among periodontitis‐affected, gingivitis and control patients. Methods The study involved 93 subjects. The participants were divided into three groups: (1) 30 subjects without periodontal disease (control group); (2) 30 subjects with gingivitis; and (3) 33 subjects with periodontitis. The oral parameters examined were as follows: (a) Simplified Oral Hygiene Index; (b) Calculus Index; (c) Gingival Index; (d) probing pocket depth; and (e) level of epithelial attachment. SA levels in saliva were measured by means of surface‐enhanced Raman spectroscopy (SERS). This method has demonstrated the capacity to detect extremely low concentrations of molecules. The spectrum was calibrated using analytical reagent SA. Results The obtained median values for SA concentrations were 5.98, 7.32, and 17.12 mg/dl for control, gingivitis, and periodontitis patients, respectively. Conclusions Our measurements by SERS corroborate that in periodontitis‐affected patients, the SA concentration is larger than their concentrations in either control or gingivitis patients. This confirms previous reports and opens the possibility of using SERS as a diagnostic tool.

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We report the synthesis of MWNTs/ZnO hybrid nanostructures. A simple, affordable, chemical procedure to functionalize MWNT with ZnO nanoparticles was performed. A significant portion of the surface of MWNTs is covered with ZnO nanoparticles, such particles form highly porous spherical nodules of 50-150 nm in diameter, sizes that are in values one order of magnitude larger than similar ZnO nanonodules reported in the literature. Hence, in the self-assembled nanocomposite the ZnO exhibits a large surface to volume ratio, which is a very advantageous property for potential catalytic applications. The resultant MWNTs/ZnO nanocomposites were characterized by X-ray diffraction, scanning and high-resolution transmission electron microscopy, and UV-Vis and Raman spectroscopies. The temperature coefficient of resistance (TCR) of the nanocomposites was measured and reported. The average TCR value goes from -5.6%/K, and up to -18%/K, on temperature change intervals from 10 K to 1 K, respectively. Based on TCR results, the nanocomposite MWNTs/ZnO prepared in this work is a promising material with potential application as a bolometric sensor.

The nitroaromatic compounds, known as organic pollutants, have arising attention due to their carcinogenic character, highly dangerous to human health. In this work, the Ag@ZnO/MWCNT ternary nanocomposite synthesized via conjugation of sonochemical and solvothermal treatments manifests high performance in the reduction of 4-nitrophenol in the aqueous media (TOF value of 246 min−1 μmol metal−1). The incorporation of MWCNT onto the nanocomposite structure favored the reusing of the catalysts even after eight consecutive catalytic runs without catalysts cleaning nor product removal. Obtained samples were characterized by XRD, TEM, UV–vis, Raman and FTIR spectroscopies. It was found that ultrasonic treatment at relatively moderate conditions leads to functionalization of MWCNT, the appearance of C=C and OH groups and change of electronic properties of Ag@ZnO/MWCNT composite which provide its stable material dispersion in aqueous solution and high catalytic performance in the 4-nitrophenol reduction. This technique may be effectively applied for the functionalization of carbon including materials for their usage in an aqueous media.

BackgroundTo demonstrate the use of surface-enhanced Raman spectroscopy (SERS) to determine sialic acid (SA) levels in saliva using silver nanoparticles as substrates, in adnexal mass patients scheduled for surgical intervention to remove invasive masses, with the aim to compare SA levels in benign tumor vs ovarian cancer patients.MethodsQuantification of SA levels was accomplished by measuring their SERS and calibrating with analytical reagent SA. The mean SA concentration in saliva from 37 benign adnexal mass resulted smaller (5.1 mg/dL) than the mean concentration in 15 Ovarium cancer patients (23 mg/dL). The cancer condition was determined by biopsy of the removed adnexal mass. The CA-125 biomarker was also measured. The predictive potential of both biomarkers is discussed, together with the malignity risk index (MRI).ResultsOur results showed a sensitivity/specificity of 80%/100% with a cutoff to distinguish between benign/cancer cases of SA 15.5 mg/dL, as established from a ROC analysis. Our results suggest that SA may be a more useful biomarker than CA-125 to detect ovarian cancer.ConclusionsOur results suggest that the SA levels measured from saliva may be as good predictors as the MRI index for the presence of ovarian cancer in sensitivity/negative predictive value and outperforms it in specificity/positive predictive value.Electronic supplementary materialThe online version of this article (10.1186/s13048-018-0433-9) contains supplementary material, which is available to authorized users.