RAPTOR: Portable, Multianalyte Bioassay Detection System
The RAPTOR™ is a rapid, automatic, portable fluorometric 4-channel assay system for monitoring toxins, viruses, bacteria, spores, fungi and other diverse targets. An extremely reliable third-generation product introduced in 2000, users have found these instruments will operate for two years or more with no breakdowns or leaks, and that they will tolerate debris-laden samples such as are produced in mailrooms and food processing facilities - impressive feats for a fully automated wet assay system.
The completely self-contained instrument is the culmination of a careful integration of optics, fluidics, electronics, and software into one compact system for laboratory and field assays. It performs user-defined, multi-step, assay protocols for monitoring fluorescently-labeled chemical reactions occurring on the surface of each of the system's four disposable optical waveguide sensors. Toxins and bacteria such as ricin and B. anthracis have been detected at levels below <1.0 ng/ml and 100 CFU/ml, respectively. Disposable assay coupons for these and many other targets are now being offered for sale (see chart under Resources tab below).
- Compact, portable system (about the size of a car battery)
- Immunoassay-based biosensor for real time or near real time detection of microbial pathogens
- Typical assay times of 10-15 minutes
- Coupons may be reused if test results continue to be negative.
- Successfully used with urine, whole blood, milk, marine water, 10% meat slurries and slurries of human waste.
- Water quality monitoring
- Laboratory testing
- Food safety monitoring
- Homeland security
- UAV's (Unmanned Aerial Vehicles)
- Download the RAPTOR data sheet
- Product Bibliography
- RAPTOR Assay Coupon Product Bulletin
- MSDS for RAPTOR bioassay coupon
- Candidate Disinfectants for Research International Products
- Bluetooth Biolink™ Wireless Unitsprovide plug-and-play wireless communication between any Research International product and a remote PC or laptop.
The following table presents sandwich assay sensitivity data gathered from researchers worldwide who have used our equipment with a variety of raw fluid samples. Sensitivity levels may vary significantly depending on many factors, and the table is presented for reference purposes only. Please refer to the attached bibliography for further information on waveguide processing and sampling methods, or contact Research International.
Sandwich Assays and Agents Detected with RAPTOR Bioassay System
|Target Agent||Liquid Media||Approx. Detection Limit||References|
|TNT||Water||440 ng/ml||5, 9, 11|
|Ricin||Water||<0.5 ng/ml||10, 15, 18, 19|
|Staphylococcal enterotoxin B||Water||0.1-0.5 ng/ml||12, 15, 16, 18, 20|
|Cholera toxin||Water||0.1-1 ng/ml||16, 20|
|D-dimer||Blood plasma||200 ng/ml||8|
|Protein C||Blood plasma||160 ng/ml||7|
|Bacillus globigii||Water||2.5 x 104CFU/ml||18, 20|
|Bacillus anthracis||Water||30 CFU/ml||Footnote (a)|
|Sterne strain, vegetative cells||Whole blood||100 CFU/ml||18|
|Ames strain, irradiated spores||Water||104-105CFU/ml||16, 18|
|Botulinium toxin||Water||1 – 10 ng/ml||6, Footnote (a)|
|Erwinia herbicola||Water||107CFU/ml||Footnote (a)|
|Yersinia pestisF1 antigen||Water||1-5 ng/ml||15, 13, 18|
|Brucella abortus||Water||7 x 104CFU/ml||18|
|Francisella tularensis||Water||5 x 104CFU/ml||15, 18, 20|
|Escherichia coliO157:H7||Hamburger slurry||100-1000 CFU/g (direct)||2, 3, 4|
|" "||0.08-0.4 CFU/g (6 hour enrichment)||17|
|Raw sewage||1000 CFU/ml||16|
|Salmonella typhimurium||Water||20,000 CFU/ml||14, 15, 16|
|Giardia lamblia||Drinking Water||5 x 104/ml||18|
|RSV||Water||Equiv. to std. ELISA||Footnote (b)|
(a) Private communication - G.P. Anderson, Naval Research Laboratory.
(b) Unpublished data - David McCrae & Ann Wilson, Research International.
1) K. A. Donaldson, M. F. Kramer and D. V. Lim, "A rapid detection method for Vaccinia virus, the surrogate for smallpox virus," Biosensors and Bioelectronics, 20, 322-327 (2004).
2) D. R. DeMarco, and D. V. Lim, "Detection of Escherichia coli O157:H7 in 10- and 25-gram ground beef samples with an evanescent-wave biosensor with silica and polystyrene waveguides," J. Food Prot, 596-602 (2002).
3) D. Lim, "Rapid Biosensor Detection of Foodborne Microbial Pathogens," Microbiological methods Forum News, 18, 13-17 (June 2001).
4) D. V. Lim, "Rapid Pathogen Detection in the New Millennium," National Food Processors Association (NFPA) Journal, 13–17 (October 2000).
5) B. Bakaltcheva, F. S. Ligler, C. H. Patterson, and L. C. Shriver-Lake, "Multi-Analyte Explosive Detection using a Fiber Optic Sensor," Analytica Chima Acta, 399, 13–20 (1999).
6) N. Nath and M. Eldefrawi, J. Wright, D. Darwin and M. Huestis, "A Rapid Reusable Fiber Optic Biosensor for Detecting Cocaine Metabolites in Urine," Journal of Analytical Toxicology, 23, 460–467 (1999).
7) J. O. Spiker, K. A. Kang, W. N. Drohan, and D. F. Bruley, "Preliminary Study of Biosensor Optimization for the Detection of Protein C,"Oxygen Transport to Tissue XX, Plenum Press, New York, 681-688 (1998).
8) B. A. Rowe,et al., "Rapid Detection of D-dimer Using a Fiber Optic Biosensor,"Thromb. Haemost., 79, 94–98 (1998).
9) B. L. Donner, et al., "Transition from Laboratory to On-Site Environmental Monitoring of 2,4,6-Trinitrotoluene Using a Portable Fiber Optic Biosensor," ACS Symposium Series, 657 (Immunochemical Technology for Environmental Applications), 198–209 (1997).
10) U. Narang, et al., "Fiber Optic-Based Biosensor for Ricin," Biosensor & Bioelectronics, 12, 937–945 (1997).
11) L. C. Shriver-Lake, B. L. Donner, and F. S. Ligler, "On-Site Detection of TNT with a Portable Fiber Optic Biosensor," Environmental Science & Technology, 31, 837–841 (1997).
12) L. A. Tempelman, et al., "Quantitating Staphylcoccal Enterotoxin B in Diverse Media Using a Portable Fiber Optic Biosensor," Analytical Biochemistry, 233, 50–57 (1996).
13) K. Cao, G. P. Anderson, F. S. Ligler J. and Ezzel, "Detection of Yersinia pestis fraction 1 antigen with a fiber optic biosensor," J. Clin. Microbiol. 33, 336-341 (1995).
14) N. Nath and M. Eldefrawi, J. Wright, D. Darwin and M. Huestis, "A Rapid Reusable Fiber Optic Biosensor for Detecting Cocaine Metabolites in Urine,"Journal of Analytical Toxicology, 23, 460–467 (1999).
15) D. R. DeMarco,et al., Rapid Detection of Escherichia coli O157:H7 in Ground Beef Using a Fiber Optic Biosensor,"Journal of Food Protection, 62, 711–716 (1999).
16) D. V. Lim, "Detection of microorganisms and toxins with evanescent wave fiber-optic biosensors," Proc. IEEE 91, 902-907 (2003).
17) T. B. Tims and D. V. Lim, "Confirmation of viable E. coli O157:H7 by enrichment and PCR after rapid biosensor detection," Journal of Microbiological Methods, 55, 141-147 (2003).
18) G. P. Anderson, C. A. Rowe-Taitt, and F. S. Ligler, "RAPTOR: A Portable, Automated Biosensor," First Conference on Point Detection for Chemical and Biological Defense (October 2000).
19) Ellen R. Goldman, Mehran P. Pazirandeh, J. Matthew Mauro, Keeley D. King, Julie C. Frey and George P. Anderson, " Phage-displayed peptides as biosensor reagents," Journal of Molecular Recognition, 13 (6), 382 – 387, 2000.
20) G. P. Anderson, K. D. King, K. L. Gaffney, and L. H. Johnson, "Multi-Analyte Interrogation Using the Fiber Optic Biosensor," Biosensors & Bioelectronics, 14, 771–777 (2000).
21) R. A. Ogert,et al., "Detection ofClostridium botuliniumToxin A Using a Fiber Optic-Based Biosensor,"Analytical Biochemistry, 205, 306–312 (1992).
Research International's biosensor systems are based on monolayer receptor-ligand reactions taking place on the surface of injection molded polystyrene waveguides. All fluidic and optoelectronic steps associated with the assay are performed automatically. The baseline protocol used to Equivalent to standard ELISA fluoroimmunoassay. In a typical waveguide-based sandwich immunoassay, the cylindrical waveguide has a monolayer of capture antibody immobilized on its surface as shown in Figure 1. Such factory-coated waveguides will maintain activity for a period of months if stabilized and not subjected to high temperatures.
Figure 1: Optical and biochemical processes associated with a waveguide bioassay.
At the time of use, the waveguide is first incubated with the fluid sample for three to five minutes. After a wash step, the waveguide is incubated with fluorophore-labeled antibody for three to five minutes to form an antibody/antigen/labeled-antibody sandwich. These molecular sandwiches generate an optical signal when excitation light is injected into the waveguide. The excitation light creates an electromagnetic 'skin effect' in adjacent fluid and it is this so-called evanescent wave electric field that excites bound reporter molecules to fluoresce. As a final step, individual molecular signals are collectively coupled into the waveguide and monitored with a sensitive photodetector that looks down the waveguide axis.
A major problem with evanescent-excited fluoroimmunoassays has been low excitation efficiency. Light injected into a waveguide is most effective at exciting surface-bound fluorophores if the light's propagation angle is near the condition of total internal reflection (TIR) at the waveguide surface. Research International has discovered and patented a novel aspheric dielectric structure that injects light into the waveguide in such a way that evanescent electric field intensities are at near-theoretical limits. This structure, the waveguide and a signal collection lens are molded as one component, providing a highly efficient, low cost, and compact optical sensor element.
Four of the waveguide sensors are mounted in a disposable plastic coupon (see Figure 2), allowing four different pathogens to be detected in a sample; or multiple channels may target the same pathogen to improve statistical certainty. An elastomer needle septum connects RAPTOR™ fluidics with fluid distribution channels molded into the coupon's body. In addition to providing controlled flow over the optical detectors, an assay recipe identification system is incorporated that automatically reads a coupon bar code when the coupon is mounted into the RAPTOR™ instrument. This bar code identifies the type of assay to be run by the instrument and allows very sophisticated assays to be performed by unskilled persons. A computer embedded within the RAPTOR™ performs and controls all steps in the assay procedure.
Figure 2: RAPTOR™ bioassay coupon.
To begin an assay, a coupon is inserted into a docking bay in the instrument's top surface. RAPTOR and coupon optics and fluidics are automatically connected when the compartment's door is closed. The user performs an assay by turning the instrument on and pressing the Run button. During the assay, a timer in the LCD display window provides time remaining until completion. On completion, assay results for the four channels are displayed.
Behind the scenes, an onboard computer reads the recipe code on the coupon, primes the coupon for flow and controls fluidics and optoelectronic steps during the assay. All fluids needed to perform an assay, with the exception of sample, are contained in the unit. Buffer and reagent are contained in flexible on-board pressurized bags, and waste in a third unpressurized bag. The reagent bag is housed in a phase-change module that keeps the reagent at a temperature of 30°C or less, preventing deterioration of any thermally sensitive reagents.
Table 1 is a summary of system specifications. The instrument package provides a backlit six-key keypad and a four-line LCD readout. The unit can talk, control, or be controlled by other instrumentation via an RS-232 channel or RF links accessed through a connector in the instrument's battery compartment. A second connector that can supply DC power to and digitally control ancillary electronics is also provided. The unit incorporates a one-megabyte nonvolatile flash memory that can store a large number of assay protocols as well as a step-by-step log of each assay performed. An on-board BA-5590/U battery provides power for 9 to 24 hours of continuous operation depending on the backlighting intensity selected. With the battery installed, overall unit weight is about 14.2 lbs (6.45 kg), and the unit's size is 11.0" W x 7.95" H x 7.29" D.
RAPTOR Bioassay System Specifications
|Use Profile:||Indoor/outdoor sample collection, transfer, and assay; storage of 63 assay recipes; user in full MOPP gear either walking or in a slow-moving vehicle.|
|Physical Size:||28 cm L x 17.3 cm W x 20.5 cm H.|
|Weight:||6.45 kg with battery, 5.6 kg without battery.|
|Operating Temperature Range:||1 to 35°C|
|Storage Range:||-29 to 66° C|
|Assay Coupon:||Four simultaneous assays; disposable; bar coded for assay identification.|
|Fluids Handling:||Bi-directional, multi-channel peristaltic pumps. Sample may be oscillated to lower assay time; reagent recovered.|
|Fluids Storage:||On-board buffer and reagent storage. Reagent stored in reusable phase-change module to limit peak temperatures.|
|Sensitivity:||Dependent on analyte; 1 – 10 ppb typical.|
|Photocurrent Resolution:||0.02 pA; 12-bit A/D.|
|Dynamic Range:||1:106(0.02 to 22, 500 pA)|
|Assay Time:||Dependent on assay, 10–15 minutes is typical.|
|Data/Command Entry:||Day/night visible keypad and display; usable in MOPP gear.|
|Visual/Audible Output:||Liquid crystal display provides positive/negative/retest; identity of agent.|
|Communication:||RS-232 bi-directional serial link and RF telemetry capability via optional BioLink™
RF Data Radio.
|Data Storage:||EEPROM retains raw or processed data for 100 assays.|
|Batteries:||8-hr continuous use; primary battery BA-5590/U, 1.05 kg (2.3 lb).|
|Power Consumptio:||7.2 W, nominal|
|Humidity:||20 – 90%, noncondensing.|
|Ancillary Equipment:||Nylon twill photographer's-style carrying case with storage for assay accessories; carry strap compatible with MOPP gear.|
|Research International reserves the right to change specifications without prior notice.|
What is the RAPTOR's ability to detect non-viable viruses or inactivated toxins?
The short answer is, "It depends." Our baseline methods use sandwich immunoassays. If the inactivation process does not destroy the surface structures that the antibody specifically binds to, then non-viable and inactivated materials would test the same as viable or active materials. If the surface is severely distorted or denatured, then sensitivity would be reduced. As real-life examples:
- Heat-killed (boiled) and live E Coli O157-H7 produce almost identical responses, but:
- Ricin toxoid, which is ricin with the toxic portion of the molecule cleaved off, produces only about 1/100 the signal of natural ricin. Viral coats are reasonably stable, so our guess would be that most viruses would mimic the E Coli experience, but that the response of an inactivated toxin would need to be empirically determined.
Is it possible to quantify the RAPTOR assay analysis?
Yes. What you do is challenge the coupon with a range of concentrations of the target analyte, and in that way obtain a response curve. While the unit will not compute concentrations directly, the data can be downloaded and the data compared with the response curve. If you had a customer that was going to buy a large number of units, we could provide custom software (hopefully, paid for by the user) that allowed you to load a response curve into the BioHawk (or RAPTOR) and which would provide a numeric output. Users generally prefer to stay away from numeric outputs, as field operators usually are more interested in and capable of understanding presence/absence, rather than actual concentration.
Has the U.S. Department of Homeland Security Safety Act Certified any portable biological detectors other than the RAPTOR?
There is only one – the Razor, a real-time PCR system from Idaho Technology, Inc. At present it is a manually operated system and cannot be set up for unattended site monitoring. It is a bit more sensitive for viruses and bacteria, but is totally blind to toxins since it requires that nucleic acids be present. That is the real Achilles heel of the nucleic acid systems – they cannot directly detect targets like ricin.
How can the disposable waveguide probes can be re-used up to 20 times? Once a virus is detected does the waveguide probe need to be thrown away?
The waveguides are coated with a target-specific antibody. If the target is not present in a sample, the coating is still good, and is available for further sample challenges. The coating is stable for maybe 24-48 hours, depending on temperature, the presence of chemicals that might cause the antibodies to become damaged, or bacteria that might like to eat the antibody coating. The secondary fluorescent reagent is stored and reused, so its life is long as well. It does not attach to the waveguide unless the target substance is present in the sample, so it is not depleted except through dilution.
Once one of the waveguides has captured some of its targeted substance, that particular waveguide is compromised, but the other waveguides (assuming they target something else) would still be unaffected. Subsequent assays may show a small positive response on that channel, even if there is no targeted substance present in later samples, due to the fact that the secondary antibody reaction is not 100% effective at labeling each captured target on the first use. This is a conscious choice on our part. By not going to equilibrium on the step where the waveguide is soaked in the secondary antibody, the assay time is significantly shortened.
We use sandwich assays to detect viruses. Can we use the same principle to detect chemicals like Sarin?
Sarin is too small a molecule to be detected. Usually, a molecule has to have a molecular weight of over 500 to have enough surface structure to be recognized by an antibody. Sarin only has a molecular weight of 140. It might be possible to engineer non-antibody based assay reactions for analytes such as Sarin, but such an option is not currently offered.
What is the difference between array, coupon and recipe?
An "array" is usually a grouping of discrete chemical reaction sites. A "coupon" is a disposable credit card-sized assay module that has fluidics and chemistry integrated together. It would have an array of capture antibody sites and fluidic channels connecting the sites to the instrument. In the BioHawk coupon, it additionally stores the secondary antibody reagent as well in small onboard reservoirs.
A "recipe" is a series of instrument operations that together, allow a user to perform an assay under total computer control. In general, these operations include turning pumps and valves on and off for programmed times, turning interrogating lasers on and off for programmed times, storing samples for confirmatory analysis, and performing aerosol sample collection for a programmed time.
RAPTOR Bioassay Consumables and Parts
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