Paul Travers

Towards an integrated electronic nose using conducting polymer sensors

Abstract This paper describes progress that has been made towards realizing an artificial nose based on arrays of conducting polymers. Electrically conducting organic polymers based on heterocyclic molecules display reversible changes in conductivity when exposed to polar volatile chemicals. In the sensor described, the polymers are interrogated for resistance changes by means of an application-specific integrated circuit (ASIC) realized in BiCMOS technology. The ASIC and the polymer array are housed on a single thick-film ceramic substrate.

Analysis of Vaginal Acetic Acid in Patients Undergoing Treatment for Bacterial Vaginosis

ABSTRACT A “gold standard” method for the diagnosis of bacterial vaginosis (BV) is lacking. The clinical criteria described by the Amsel technique are subjective and difficult to quantify. Alternatively, the reading of Gram-stained vaginal smears by scoring techniques such as those that use the Nugent or Hay-Ison scoring systems is again subjective, requires expert personnel to perform the reading, and is infrequently used clinically. Recently, a new diagnostic device, the Osmetech Microbial Analyzer—Bacterial Vaginosis (OMA-BV), which determines a patients BV status on the basis of measurement of the amount of acetic acid present in a vaginal swab specimen, was approved by the Food and Drug Administration. The present study uses the conducting polymer gas-sensing technology of OMA-BV to measure the concentration of acetic acid in the headspace above vaginal swab specimens from patients undergoing treatment for BV with metronidazole. In 97.8% of the cases the level of acetic acid detected fell sharply during the treatment period, crossing from above to below the diagnostic threshold of 900 ppm. The diagnosis obtained on the basis of the level of vaginal acetic acid was compared with the diagnoses obtained by use of the Amsel criteria and the Nugent scoring system both at the time of initial entry into the study and at the repeat samplings on days 7 and 14. The results obtained with OMA-BV showed overall agreements compared with the results of the Amsel and Nugent tests of 98 and 94%, respectively, for the 34 patients monitored through the treatment process. This provides further evidence that the measurement of vaginal acetic acid by headspace analysis with conducting polymer sensors is a valid alternative to present tests for the diagnosis of BV.

Odor Evaluation of Foods Using Conducting Polymer Arrays and Neural Net Pattern Recognition

An increasing need exists for chemical sensing systems that mimic biological olfaction. Examples of potential applications of such systems are in quality control of foods and beverages and environmental monitoring.