title: Single particle multichannel bio-aerosol fluorescence sensor.
abstract: We describe a prototype low-cost multi-channel aerosol fluorescence sensor designed for unattended deployment in medium to large area bio-aerosol detection networks. Individual airborne particles down to ~1mum in size are detected and sized by measurement of light scattered from a continuous-wave diode laser (660nm). This scatter signal is then used to trigger the sequential firing of two xenon sources which irradiate the particle with UV pulses at ~280 nm and ~370 nm, optimal for excitation of bio-fluorophores tryptophan and NADH (nicotinamide adenine dinucleotide) respectively. For each excitation wavelength, fluorescence is detected across two bands embracing the peak emissions of the same bio-fluorophores. Current measurement rates are up to ~125 particles/s, corresponding to all particles for concentrations up to 1.3 x 104 particles/l. Developments to increase this to ~500 particles/s are in hand. Device sensitivity is illustrated in preliminary data recorded from aerosols of E.coli, BG spores, and a variety of non-biological materials.
authors.forename: P
authors.initials: P
authors.lastname: Kaye
authors.forename: W R
authors.initials: WR
authors.lastname: Stanley
authors.forename: E
authors.initials: E
authors.lastname: Hirst
authors.forename: E V
authors.initials: EV
authors.lastname: Foot
authors.forename: K L
authors.initials: KL
authors.lastname: Baxter
authors.forename: S J
authors.initials: SJ
authors.lastname: Barrington