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A novel identification technique called antibody profiling was examined as an alternative to DNA-based methods for matching crime scene evidence to a suspect. This technique provides results within 2 hours, is 1/100 the cost of DNA tests, and does not require skilled technicians or expensive equipment. A matrix of 422 blood samples were prepared to mimic typical crime scene conditions and provide validation for the technique. The effects of sample size, drying temperature, binary and ternary blood mixtures, adulteration with chemicals, and placement on a variety of surfaces were examined. Using the antibody profiling method, 91% of the 422 samples were correctly identified. In addition, binary blood mixtures could be identified with up to 40% contaminating blood. Temperatures at or above 60 degree(s)C and the presence of soil in the samples interfered with the ability to correctly identify samples. In this study, the antibody profiling technique was shown to be an excellent alternative to DNA-based identification methods. This method will find applications in situations where results are needed rapidly, where it is necessary to screen multiple suspects, and in remote areas where the equipment and technical skills needed for DNA testing are not available.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A fiber-optic immunosensor was used to determine concentrations of the mycotoxin fumonisin B1(FB1) in both spiked and naturally contaminated corn samples. Samples were extracted with a mixture of methanol/water. Two methods were used to prepare the methanolic corn extracts before introduction to the immunosensor: (1) simple dilution of the methanolic corn extract; or (2) affinity column cleanup. The sensor displayed an IC50 of 70 ng FB1/mL when toxin was introduced in phosphate buffered saline. Simple dilution of methanolic corn extracts yielded an assay with an IC50 equivalent to 25 (mu) gFB1/g corn and a limit of detection of 3.2 (mu) g/g corn, while affinity cleanup of corn extracts yielded an assay with an IC50 of 5 (mu) gFB1/g corn and a limit of detection of 0.4 (mu) gFB1/g corn. The difference in sensitivity between the two cleanup techniques was due to concentration of fumonisins obtained from the affinity cleanup procedure. Naturally contaminated corn samples were also analyzed after either simple dilution or affinity column cleanup. For comparison the naturally contaminated corn samples were analyzed with an HPLC method after isolation of the fumonisins with strong anion exchange (SAX) solid phase extraction cartridges. The SAX/HPLC method and the immunosensor method agreed well except when large amounts of other fumonisins (i.e. fumonisin B2) were present. This was due in part to the cross-reactivity of the monoclonal antibody with other fumonisins. The immunosensor has the potential to screen individual corn samples for fumonisins within six minutes, and is among the fastest of the currently available FB1 detection methods.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.