Visite du Dr Frank Christnacher (ISL)

Transcription

1 R & D pour la défense Canada Visite du Dr Frank Christnacher (ISL) Mesure lidar avec la chambre d aérosol de DRDC Valcartier Effet du milieu de culture sur la signature spectrale des bactéries Christian Laflamme, J.R. Simard, S. Buteau, B. Déry, D. Nadeau, P. Lahaie, C. Duchaine, P. Mathieu, G. Roy, O. Houle, H. Lavoie 27 septembre 2010

2 Presentation outline Presentation of the Lab-size lidar bioaerosol chamber Research question Experimental process Results Conclusion Future work 1

3 Lab-size aerosol chamber - Objectives Built a library of fluorescing aerosols and reduce cost Increase understanding of aerosol spectral properties Demonstrate spectrometric correlation between laboratory chamber and open-air results Study the influence of experimental parameters on the spectral signature of fluorescent aerosols in a laboratory environment 2

4 3 Lab-size aerosol chamber

5 Lab-size aerosol chamber Main Chamber Spectrometer ICCD Mixing chamber Beam expander Telescope Particles counter 4

6 Lab size chamber Key characteristics Telescope Commercial Newtonian F/4 Spectrometer F/3, nm range on ICCD ICCD camera 675 intensified pixels (18 mm) Laser source 355 nm 20 Hertz 5

7 6 Lab size chamber aerosol powder input

8 Issue of Interest Is the growth media influence the spectral signature of the bacteria? 7

9 Experimental plan Compare spectral signature of 1. Growth media alone 2. Bacteria culture in growth media 3. Bacteria culture in growth media and triple washed Growth media Tryptic soy broth (TSB) Nutrient broth (NB) Brain and hearth infusion (BHI) Bacteria Bacillus globigii (BG) Bacillus thuringiensis (BT) Erwinia herbicola (EH) *All samples are dry release (powder) 8

10 Bacteria Growth curve in culture media Spores (as BT and BG) 9

11 Spectral signatures extraction Fluorescence from material Integrated fluorescence signal Background Injection of material Acquisition # 10

12 Spectral signatures extraction Subtraction of mean passive and LIF background (red) Mean of all substantial acquisition LIF (green) Smoothing and normalization (black) 11

13 Signature robustness Repeatablity from sample to sample 10 different samples of BHI 12

14 Signature specificity Capacity to discriminate different material TSB BHI NB 13

15 TSB Result BG BT Growth media alone Bacteria in the growth media Triple washed bacteria EH NB BHI 14

16 BG LOG TSB BG growth in TSB TSB BG growth in TSB triple washed TSB and BG in TSB give very similar spectral signatures Triple washed BG is significatively different 15

17 BG LOG TSB Principal component analysis (PCA) BG growth in TSB TSB BG growth in TSB triple washed TSB and BG in TSB are different using PCA 16

18 TSB Result BG BT Growth media alone Bacteria in the growth media Triple washed bacteria EH NB BHI 17

19 BT LOG NB BT growth in NB NB BT growth in NB triple washed Only slight discrepancy (and barely significative) between NB and BT growth in NB and triple washed sample 18

20 BT LOG NB Principal component analysis (PCA) NB BT growth in NB BT growth in NB triple washed PCA clearly discriminate the three type of sample 19

21 TSB Result BG BT Growth media alone Bacteria in the growth media Triple washed bacteria EH NB BHI 20

22 EH LOG BHI EH growth in BHI BHI EH growth in BHI triple washed Clear difference between the three sample 21

23 EH LOG BHI Principal component analysis (PCA) EH growth in BHI triple washed EH growth in BHI BHI PCA analysis improve the discrimination 22

24 Conclusion The lab-size lidar bioaerosol chamber proves to be a robust and specific tool to study the factor affecting fluorescent signatures; The growth media contributes, in various degree, to the fluorescent spectral signatures; PCA analysis improves the discrimination between the different samples; We suggest to include the signature of different growth media in the signature library; 23

25 Futur work Build a database of biological signatures for BioSense and SR- Biospectra Increase the understanding of fluorescence for biological standoff detection Design an improved lab-size lidar bioaerosol dissemination chamber Chamber s second generation Improved radiometric properties Increased control of the aerosol circulation/homogeneity 24

26 25 Chamber s second generation

27 26 Questions?

28 27