Table 2.

Overview of key characteristics of portable platforms for multiplex detection of security sensitive toxins (adapted from [54,55]).

Feature	Minimal Requirement	Optimal Requirement
Scope of the Platform
Intended use case	Multiplex identification of panels of security sensitive toxins	Multiplex identification of proteotoxins and low molecular weight toxins, plus identification of biological warfare agent (BWA)-relevant bacteria, spores and viruses
Operation site	Mobile laboratory (functioning laboratory with trained personnel, inconsistent electricity supply, limited climate control)	On-site, i.e., in the hot zone (minimally trained staff, no electricity, no climate control, dust)
User	Trained personnel, i.e., specialized personnel for BWA detection in fire brigades, analytical task forces or military	Minimally trained personnel, i.e., first responders
Instrument
Instrument design	Single integrated instrument with port(s) for reading one or more multiplex assays (cartridges) for simultaneous detection of multiple security sensitive toxins
Size	Small, portable instrument (approx. 50 cm × 50 cm × 25 cm or smaller)
Weight	≤15 kg	≤4.5 kg
Power requirements	Local 110–220 AC mains power, plus uninterruptable power supply plus rechargeable battery with 4-h operation	Same, with rechargeable battery (8 h operation)
Throughput	Up to 8 sample runs per instrument per 8 h day	Up to 40 sample runs per instrument per 8 h day
Environmental stability-Operating range of platform	Operation at 10–35 °C and up to 90% non-condensing humidity	Operation at 5–45 °C and up to 90% non-condensing humidity
Biosafety	Closed, self-contained system; easy decontamination of instrument surface as well as possibility for decontamination of whole instrument using formaldehyde or hydrogen peroxide fumigation
Training	<2 days training for minimally skilled staff	<1 day training for minimally skilled staff
Operation	<1% operation error for a trained user Operation in full protective equipment Automated analysis and interpretation of measurement data
Calibration	Need for instrument calibration on-site on a yearly basis by minimally trained technician	Self-check alerts operator to instrument errors or warnings; no calibration needed
Result readout	Qualitative result available to user sufficient to inform responsible person for decision-making	Same, plus quantitative result for each analyte
Data display	On-instrument or on a separate reading device (mobile phone, tablet PC) with ability to function in various light conditions. Generation of report file with information about sample ID, operator ID, date, location, assay applied etc.
Connectivity	USB, integrated Local Area Network (LAN) port, integrated Wi-Fi	Same, plus integrated Bluetooth, multi-band Global System for Mobile Communications (GSM) chipset 2G, 3G, LTE, 5G
Manufacturing	ISO 9001:2015 compliant	ISO 13485:2016 compliant
List price of instrument	≤$50,000 (USD)	≤$10,000 (USD)
Assay Cartridge
Analytes	Simultaneous detection of proteotoxins as well as low molecular weight toxins from a single sample using one or more assay cartridges	Simultaneous detection of proteotoxins as well as low molecular weight toxins from a single sample using one universal cartridge; additional analyte detection capabilities preferred (e.g., nucleic acid testing for determination of presence of toxin producing organism)
Multiplexing capability	Analysis of one sample for the presence of six security relevant toxins at the same time in one or more assay cartridges	Analysis of one sample for the presence of 15 security relevant toxins at the same time in one or more assay cartridges
Test kit	All materials required for the assay, including assay cartridge, reagents and buffers included in individually packaged test kits
Additional third-party consumables	None, except for sample collection and sample preparation	Cartridges contain all required reagents
Sample type	Ability to accept a wide range of environmental (e.g., soil, dust), food (e.g., milk, water), powder (e.g., bentonite, kaolin) as well as clinical (e.g., serum, whole blood, urine, nasopharyngeal swabs) samples
Sample volume	The minimal sample volume required to reach relevant sensitivities (up to 1 mL acceptable)
Sample preparation	Minimal sample preparation; no more than 3 steps such as pipetting, filtration or other off-cartridge-based steps acceptable	All sample preparation steps are integrated and performed within the assay cartridge; no precision steps required to be performed by the user
Limits of detection (LOD) in multiplex format	Achieving LODs in the range of LD50 of the security sensitive toxins	Equivalent (or improved) relative to reference assays
Specificity—inclusivity	Detection of all congeners of a toxin group or subtypes/ isoforms of a proteotoxin, respectively
Specificity—exclusivity	No significant cross-reactivity with closely-related proteins or molecules outside the scope of security sensitive toxins
Interfering substances	No interference for an individual analyte or mixtures of analytes because of interfering substances
Time to result	<60 min	<20 min
Internal process controls	Internal process control must be integrated into the assay design
Positive/Negative controls	External positive and negative controls are not required for each test but are performed on a regular basis	External positive and negative controls are not required for each test and do not need to be run on a regular basis
Environmental stability–transportation	No cold chain requirements; stable at 2–45 °C for up to 7 days, can tolerate short term temperature fluctuations from 0–50 °C	No cold chain requirements; stable at 2–45 °C for up to 15 days, can tolerate short term temperature fluctuations from 0–50 °C
Environmental stability–Operating range	10–35 °C	5–45 °C
Shelf life and storage conditions	12 months from date of manufacture at up to 25 °C	18 months from date of manufacture at up to 30 °C
Manufacturing	ISO 9001:2015 compliant	ISO 13485:2016 compliant
List price of assay per sample	≤$50 (USD)	≤$20 (USD)