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A review on bioaerosol science, technology and engineering: current and beyond Maosheng Yao College of Environmental Sciences and Engineering Peking University.

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Presentation on theme: "A review on bioaerosol science, technology and engineering: current and beyond Maosheng Yao College of Environmental Sciences and Engineering Peking University."— Presentation transcript:

1 A review on bioaerosol science, technology and engineering: current and beyond Maosheng Yao College of Environmental Sciences and Engineering Peking University

2 Outline Bioaerosol Emissions Air Sampling Techniques Biological Assessment, Detection and Control Current State of Bioaerosol Research

3 Particles of biological origins --bacteria, fungi, viruses, pollen --their derivatives such as endotoxins, glucans, and mycotoxins --fungal allergens, indoor house dust mites, dog, cat allergens Biological Agents in the Environments 0.5-2μm for bacteria & 2-5μm for fungi commonly found, viruses are usually below 0.3 μm

4 Bioaerosol Emissions 1)Natural environments 2)Human and animal are sources of bioaerosol 3)Waste recycling, bio-solid land application, composting, agriculture, pharmaceutical and bio-tech activities 4)Hospital settings (surgery, organ transplant, and dental treatment) 5)Bioterrorism events

5 Exposure to the biological agents presents a serious health challenge both for public and private sectors Why Are We Concerned about These Biological Agents? Respiratory diseases such as asthma, pneumonia, and allergies. Infectious diseases such as SARS, and Bird Flu. SARS outbreak in 2003 Influenza (bird flu) Outbreak

6 Global Asthma Impacts According to WHO estimates, 300 million people suffer from asthma and 255, 000 people died of asthma in 2005 USA Brazil Canada Australia China

7 Pneumonia Death in Children < 5 Years Old WHO estimates that up to 1 million children under 5 die each year from pneumonia.

8 Annual Impacts of Epidemic Influenza Estimates for the US Cases: millions Days of illness: millions Work & school loss: tens of millions Hospitalizations: 85, ,000 Deaths: 34,000-50,000 Economic loss: billions of dollars MMWR 2003; 52 (RR-8); Thompson et al. JAMA 2003; 289:179 Thompson et al., JAMA 2004; 292:1333; Adams PF et al. Vital Health Stat 1999; 10(200) In addition, infectious diseases took a tremendous toll both on human and economy

9 Global Outbreak of SARS in 2003

10 Social Impacts of SARS

11 Increasing Threat of Bio-terrorism That May Release Lethal Airborne Biological Agents

12 The first critical step for monitoring, assessment, or control strategy for the biological inhalation exposure Bio-Sampling

13 Air Sampling Techniques Impactors Liquid impingers Filters Electrostatic precipitator

14 Andersen six-stage impactor was developed in the 50s and widely used as a standard for bioaerosol sampling BioStage Impactor (SKC, Inc., Eighty Four, PA) --collect microorganisms onto agar surface Liter/min with an impaction velocity of 24m/s BioStage Impactors It was used in anthrax investigation

15 Principle of Collection by Impactor

16 Becoming more popular for sampling airborne biological agents -- Battery-powered, portable, easy to handle -- High volume sampling, more than 100 L/min Portable Microbial Impactors

17 Particle Collection of Portable Samplers

18 Microflow 120 L/min Bio-Culture 120 L/min SMA MicroPortable 28.3/141.5 L/min Portable Microbial Impactors

19 RCS High Flow 100 L/min Millipore Air Tester 140/180 L/min SAS Super L/min Portable Microbial Impactors They have been used in military sites

20 MAS L/min Portable Microbial Impactors These samplers are increasingly being used for bio-sampling Their sampling performances are not fully described or investigated Investigation of physical and biological collection efficiencies

21 Sampler Testing System Yao, M. and Mainelis, G. Aerosol Sci. Technology, 2006, 40:1-13.

22 Physical Collection Efficiencies & Cutoff Sizes of Seven Portable Microbial Samplers When Sampling PSL Particles Yao, M. and Mainelis, G. Aerosol Sci. Technology, 2006, 40:1-13. anthrax Virus

23 Comparison of Sampler Performance with Particle Inhalation and Deposition in Human Lung Yao and Mainelis, J. of Exposure Analysis and Env Epi, (2007), 17, 31–38

24 Biological Collection Efficiency the ability of the sampler to not only collect, but also keep the viability of the bio-particles

25 Influences of Jet Velocity and Jet-to-plate Distance on Biological Collection Efficiency

26 Air sampling Techniques filtration gelatin filter Anthrax surrogate

27 Air Sampling Techniques BioSampler 1) Liquid Impinger, use of centrifuge and impaction to collect aerosol particles with a sampling flow rate of 12.5 L/min 2) Longer sampling time up to 8 hours 3) Transferring aerosols into hydrosols Powerful aerosol-2-hydrosol sampling techniques are needed BioSampler

28 Bio- sampling Challenges Impaction-based sampling techniques were shown to cause damages to the viability of microorganisms Virus is too small to be collected by these techniques & their sampling method is significantly lacking There is a need to develop a more advanced sampling strategy

29 Electrostatic collection is a mechanism of collecting the airborne charged particles using the electrical force Collection velocity is about 2 to 4 orders of magnitude lower than that of BioStage impactor (24 m/s) Lower mechanical stress and less desiccation upon the microorganisms being sampled Electrostatic Collection

30 Electrosampler was designed to investigate if natural charges of microorganisms can be used for their effective electrostatic collection Yao and Mainelis, Journal of Aerosol Science, 2006, 37:

31 Physical Collection Efficiency of Electrosampler Electrostatic field, 5kV/cm, was used Electrostatic field may have the ability to collect viruses

32 Comparisons of outdoor bacteria sampling using Electrosampler and BioStage impactor Electrostatic method provides a better biological quantification

33 Use of Electrostatic Field in Collecting Airborne Toxins

34 Use of Electrostatic Field in Collecting Airborne Allergens

35 Bioaerosol Detection and Assessment (Combining Physical, Biochemical and Molecular Techniques ) The electrostatic method demonstrates ability in collecting viruses from the air. Virus concentration could be very low in the air, even collected, might not be enough to be detected. Combination of electrostatic method with advanced molecular techniques such as qPCR and ELISA may offer a solution, e.g., for detecting influenza A virus.

36 Globally confirmed human cases of H5N1 avian influenza since 2003

37 Influenza A Virus Commonly known as flu, is an infectious disease of birds and mammals caused by an RNA virus Typically, influenza is transmitted from infected mammals through the air by coughs or sneezes, creating bioaerosols containing the virus Currently, the strand is only limited to animals, but it is very likely to mutate further becoming a human-to-human case. Hong Kong Flu (magnified approximately 70,000 times) in May 1997

38 In 1918, Spanish flu killed 675,000 people in the U.S. and an estimated 20–50 million people worldwide Spanish Flu in 1918

39 Virus particles Air Out E Detection of influenza A Virus Metal Plate qPCR ELISA Metal PlateBiosensor + Air In 96-well-plate Endotoxin/Glucan Yao et al. (2007) Integration of Technologies for Constant Monitoring of Exposure [E-Letter], Science.

40 Environmental Allergens Common Allergens? House dust allergens (Der p 1 and Der f 1), cat allergens Fel d 1 (cat), dog allergen Can f 1 (dog), Bla g 1 (cockroach), Bla g 2 (mouse) fungal allergens, e.g., Alternaria alternata allergen Alt1 Enzyme-Linked ImmunoSorbent Assay (ELISA) is often used to analyze allergens

41 ELISA Sample Processing Dust Sieving (>30 mg) Dissolve into 1.5 mL PBS 0.05% Tween 20 centrifuge 20 min shaking 2 h supernatant 96-well plate Antibody coated plate

42 Procedure of ELISA tests ELISA can be used together with air sampling technique for measuring airborne viruses and allergens

43 House Dust Mite (Der p & Der f 1)

44 Principle of LAL/Glucatell Assay (airborne endotoxin and glucan) LAL Factor CFactor G LAL Factor B Endotoxin (LPS) LAL Activates Preclotting Enzyme LAL (1,3)-β-D-glucan LAL pNA (yellow) Substrate Ac-Ile-Glu-Ala-Arg-pNA. Horseshoe crab LAL (Limulus Amoebocyte Lysate)

45 LAL/Glucatell Filter Extraction 0.05% Tween 20 for Endotoxin 0.5 N NaOH for glucan, neutralized by Tris-HCL Dilution (10 -3 ) Add sample extracts, standards into 96 well plate Incubation (15 min at 37 o C) add LAL or Glucatell Agents Placed inside spectraphotometer Log(Y)=A+Log(X) min

46 Results for Road Dust In collaboration with Lovelace Respiratory Research Laboratory

47 Results for Road Dust

48 qPCR for quantification of microbial species Selection or design of primer sets for specific microbial species (alternaria spp) Design of probes for specific allergens & develop standard curves quantitative-PCR tests for DNA extracts from environmental samples DNA extractionPrimers & ProbesStandard Curve qPCR tests Primary tasks include:

49 qPCR for quantification of microbial species qPCR reaction mixture: Template DNA Forward/Reverse Primers, Probes dNTPs DNA Polymerase Buffer Tris, KCl, Mg 2+, BAS, etc.

50 qPCR Application Curves Vesper et al, 2005, American Laboratory, pp Sample 19

51 Quantification of Environmental Sample qPCR can be used for detecting airborne low concentration biological agents Eff=10 (-1/slope) -1 Xn=X 0 (1+E) n

52 Other Bioaerosol Detection Techniques 1) Bioaerosol mass spectrometry (BAMS) (Herbert et al., 2005) 2) Surface-enhanced Raman spectroscopy (Sengupta et al., 2007) 3) Flow cytometry with fluorochrome (Chen and Li, ) Bio-functional oligonucleotides based techniques such as aptamer (Brody et al., 1999) 5) Nanowire-based detection techniques All these techniques can be also used for detecting airborne low concentration biological agents

53 Microorganism Inactivation Yao and Mainelis, Environmental Science Technology, 2005, 39:

54 Survival rates of P. fluorescens bacteria when deposited on MCE filter and exposed to the electrostatic field Yao and Mainelis, Environmental Science Technology, 2005, 39:

55 Use of nano-scale Zero Valent iron particles in Inactivating Microbial Species FE-SEM Images NZVI particles Iron Oxides Shaking-oxidization Characterization of nanoscale iron particles

56 Inactivation of B. subtilis by NZVI particles

57 Characterization of the Inactivation of B. subtilis (a)(b) (c)(d) Pure BST NZVI+BST Aerobic NZVI+BST anaerobic FeOOH+BST Aerobic

58 Inactivation of P. fluorescence by NZVI

59 Matthew T. Cabeen & Christine Jacobs- Wagner Nature Reviews Microbiology 3, (August 2005) Inactivation Mechanisms by NZVI Gram-positive Gram-negative

60 Inactivation of A. versicolor by NZVI

61 Characterization of the Inactivation of A. versicolor Submitted to Applied & Environmental Microbiology

62 Summary of NZVI Inactivation Inactivation was fast and efficient, within 5 minutes, all B. subtilis were inactivated Due to its small size, the inactivation efficiency was very high, and 10mg/ml can achieve good results The inactivation depended on the membrane type of the microbial species, e.g., no effects on fungi species tested

63 Other Biological Control Technologies Biofiltration (Sanchez-Monedero et al., 2003) X-Ray enhanced electrostatic field Photocatalytic materials such as TiO 2 have been investigated (Pal et al., 2005). Cold plasma (Birmingham and Hammerstrom, 2000) and UV light (Tseng and Li, 2005) Control of air stream, e.g., negative pressure rooms

64 Current Research Areas of BioAerosol Science Integration of bioaerosol science with molecular science such as qPCR, PCR, and ELISA High volume of sampling: Portable Microbial Sampler, aerosol-2-hydrosol techniques Investigation of the link between bioaerosol exposure and health effects Development of high throughput environmental bio- sensor

65 Combining bioaerosol with physics, chemistry, bio-medical engineering and molecular techniques Drug delivery to the lung using aerosol technology Human early disease detection such as lung cancer Inactivation of BioAerosols Current Research Areas of BioAerosol Science

66 Biological Exposure Assessment and Control Bioaerosol Emission Air Sampling Exposure Assessment Detection Biological Control Human Biological Exposure PreventMinimize

67 Collect Detect Control CDC Biological Exposure Assessment and Control

68 Bioaerosol field is multidisciplinary, and requires many areas of expertise

69 Thank you !!! Maosheng Yao PhD PKU 100 Scholar Program Professor Web:


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