Real-Time Detection of Biological Pathogens in Urban Environments Laura Barry Hung Phan Gloria See Introduction to Biosensors Presentation 2 - 4/5/2011

Project Details Pathogen: agents known to cause disease in living organisms such as plants, animals, and humans –Bacteria –Viruses –Biotoxins –Fungus A review of biosensor technology for real- time pathogen detection in urban environments.

Traditional Methods of Detection & Identification Sample w/ unidentified agent: Air, soil, food/water, sputum etc. Culture Enhancement Selective/Differential Plating Isolation and subculturing Inoculation for physiological tests Evaluation of physiological tests Molecular based, non-culture techniques (Feng, Brown Zourob)

Basic components of sensor system Sample: air, water, etc. Trigger: primary detector (continuous monitoring) Cue: secondary detector Collector: increases amount of unknown agent Detector: biological or non-biological Identifier: based on preselected characteristics of target pathogens (DOJ: NIJ)

Different approaches through technology development Point detection Standoff technologies Structure based identification Nucleic Acid sequence identification Cell-based Light scattering Optical Infrared Two-component reporter system

Current Biosensor Systems Diagnostic Assays –Uses probes and assays to identify Pathogen –Identifies known select genome strands in pathogen to detect families of pathogen –Identifies full strands of known genome to identify specific pathogen –Sensitive –Fast –Expensive (Citation, Cohen)

Current Biosensor Systems (cont’d) Microfluidics –Tiny chips that have fluid channels and sensing chambers –Lab-on-chip –Uses nucleic acid-base to detect pathogens E-noses Can identify single molecule in samples Can flag DNA strands –Ergonomic, Fast, Expensive (citation, Whitesides)

Current Biosensor Systems (cont’d) Optical Sensors –Fluorescence Optical multisensors, usually with each specialized with a single reactant organic materials react with the sensing surface and change the intensity of the light Surface Plasmon Resonance target is collected object’s surface is excited by a light source and it oscillates to a certain frequency (Citation,Pattnaik)

Current Biosensor Systems (cont’d) Bioreporters –using cells or other organisms to detect relevant stimuli –utilizes inherently rapid response times of cellular signaling –easy to use –reporting system needs to be established in advance –organisms need to be maintained in their testing environment (citation Attunes, Sengupta)

Current Biosensor Systems (cont’d) Other approaches –Electrochemical: Used for DNA and immunusensors –Electromechanical: Usually mass- change sensors that attract pathogens –Chemical: Detecting specific compounds native to specimen, usually utilizing surface chemistry (Sengupta)

Current Biosensor Systems (cont’d) Nanomaterials –Coupled with other sensing technologies, nanomaterials expand the potential for biosensors –Cell and molecule scale features make detection easier –Sensitivity and threshold limits are improved –Increased surface area gives more room for substrates to be treated, detection and increases device sensitivity (Yanik, Jinseok)

Relevant Applications: Airport, subways, high human traffic environments (DHS, TSA) Transportation Security Administration Borders, ports (DHS, DOS) Battlefield Infrastructure (WHO, EPA, industry, National Biodefense Program) Emergency Responders

Challenges in Biosensor Technology Detection limits/sensitivity Multisensor devices Reliability/accuracy of detection Speed of analysis Field environments Reusable, robust devices Cost of fabrication and testing