Fluorescent biological particle detection system
First Claim
1. Apparatus for identifying the existence of viable biological particles within an airstream containing a mixture of biologically viable and biologically inert particles, comprising:
- means for directing the particles individually and sequentially along a substantially linear path through air;
means for calculating the position of each particle as a function of time;
a source for emitting an ultraviolet laser beam when the calculated position of the particle is such that it is passing the laser beam source, said beam being directed to contact each particle moving along its linear path in the air and having a wavelength operative to excite biomolecules contained therein to produce fluorescence;
means for measuring the intensity of the fluorescence emitted from each particle and producing a signal indicative thereof, said intensity being measured during the period of time when the position of the particle is calculated to be substantially coincident with the ultraviolet laser beam; and
means for comparing each particle'"'"'s fluorescence intensity signal against pre-determined criteria and establishing whether that particle is a biologically viable particle or an inert particle.
3 Assignments
0 Petitions
Accused Products
Abstract
A process and apparatus are provided for detection of viable and potentially hazardous biological particles which may be dispersed in a particulate-containing airstream. The process comprises directing each of the contained particles along a linear path through air, in a sequential manner, and sampling them for determination of their size, whether they are biological and viable, and whether they are present in concentrations greater than background levels. The particle size identifies the particles as respirable or not and the particles are characterized as biological and viable by subjecting each particle in turn, to 340 nm, ultraviolet laser light and looking for the emission of fluorescence which is typically emitted from bacteria or bacterial spore. Fluorescence detected in the 400-540 nm range signals the presence of nicotinamide adenine dinucleotide hydrogen, which is indicative of biological activity or viability. A more compact, and power-saving apparatus results with the preferential use of a solid state, ultraviolet laser, which is actuated only when the particle is passing the laser and only if it is deemed to be a biologically viable candidate.
176 Citations
18 Claims
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1. Apparatus for identifying the existence of viable biological particles within an airstream containing a mixture of biologically viable and biologically inert particles, comprising:
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means for directing the particles individually and sequentially along a substantially linear path through air; means for calculating the position of each particle as a function of time; a source for emitting an ultraviolet laser beam when the calculated position of the particle is such that it is passing the laser beam source, said beam being directed to contact each particle moving along its linear path in the air and having a wavelength operative to excite biomolecules contained therein to produce fluorescence; means for measuring the intensity of the fluorescence emitted from each particle and producing a signal indicative thereof, said intensity being measured during the period of time when the position of the particle is calculated to be substantially coincident with the ultraviolet laser beam; and means for comparing each particle'"'"'s fluorescence intensity signal against pre-determined criteria and establishing whether that particle is a biologically viable particle or an inert particle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Apparatus for identifying the existence of viable biological particles within an airstream containing a mixture of biologically viable and biologically inert particles, comprising:
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an air discharge nozzle capable of accelerating the flow of the particle-containing airstream through the nozzle so that the particles exit the nozzle individually and sequentially along a substantial linear path, the air flow acting to accelerate the particular particle passing through the nozzle due to the aerodynamic drag acting thereon, said particle resisting the acceleration by its inertia, whereby the velocity of the particle exiting the nozzle is less than that of the airstream; means for measuring the velocity of the airstream and producing a signal indicative thereof; means for emitting spaced apart laser beams, both of which intersect the particle'"'"'s linear path, the first beam intersecting the path adjacent the nozzle, the second of beam being spaced a known distance downstream; means for measuring the time taken for the particle to move between the first and second laser beams and producing a signal indicative thereof; and means for processing the known distance between the first and second laser beams and the time signal so as to establish the velocity of the particle and producing a signal indicative thereof; means for processing the difference between the particle velocity signal and the airstream velocity signal so as to establish the size of the particle; means for processing the signals for the particle'"'"'s size and comparing it against pre-determined criteria and establishing whether the particle is a candidate as being a biologically viable particle; means for calculating the position of the candidate particle as a function of time and producing a signal indicative thereof; a source for repeatedly emitting an ultraviolet laser beam in discontinuous pulses, each laser beam pulse being directed along a light path which intersects the path of each particle moving along its linear path in the air, said beam having a wavelength operative to excite biomolecules contained therein to produce fluorescence; means for selectively triggering a ultraviolet laser beam pulse when the calculated position of the candidate particle corresponds with the intersection of the particle'"'"'s linear path and the ultraviolet laser light path; means for measuring the intensity of the fluorescence emitted from each candidate particle and producing a signal indicative thereof; and means for comparing each candidate particle'"'"'s fluorescence intensity signal against pre-determined criteria and establishing whether that particle is a biologically viable or an inert particle. - View Dependent Claims (10, 11, 12, 13)
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14. A process for the detecting the existence of viable biological particles within a stream of air containing a mixture of biologically viable and biologically inert particles, comprising the steps of:
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(a) continuously processing the stream of air so as to direct the particles along a substantially linear path through air in a sequential manner; (b) calculating the position of each particle as a function of time; (c) providing an ultraviolet laser source for producing a beam of ultraviolet light directed along a light path; (d) actuating the laser source and emitting an ultraviolet laser beam when the calculated position of the particle is substantially coincident with the light path of the laser beam so that the ultraviolet laser beam contacts the particle, the laser beam having a wavelength suitable to excite biomolecules contained therein and produce fluorescence; (e) detecting fluorescence from the particle and establishing its intensity; (f) comparing the intensity of the particle'"'"'s fluorescence against pre-determined criteria so as to establish whether that particle is biologically viable or is an inert particle; and (g) performing the steps (b)-(f) for the next particle in sequence.
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15. A process for the detecting the existence of viable biological particles within a stream of air containing a mixture of biologically viable and biologically inert particles, comprising the steps of:
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(a) continuously processing the stream of air so as to direct the particles along a substantially linear path through air in a sequential manner; (b) measuring biological characteristics associated with each particle; (c) comparing the particle'"'"'s biological characteristics against pre-determined criteria and establishing whether that particle is a candidate as being a biologically viable particle; (d) selectively contacting the candidate particle with an ultraviolet laser beam having a wavelength suitable to excite biomolecules contained therein and produce fluorescence; (e) detecting fluorescence from the candidate particle and establishing its intensity; (f) comparing the intensity of the candidate particle'"'"'s fluorescence against pre-determined criteria so as to establish whether that particle is biologically viable or is an inert particle; and (g) performing the steps (b)-(f) for the next particle in sequence. - View Dependent Claims (16, 17, 18)
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Specification