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TPX technology

What is TPX technology?

mariPOC and mariAST utilize ArcDia’s own patented TPX (Two-Photon Excitation) assay technology. The technology has been shown to be suitable for all applications typically performed in clinical laboratories based on immunoassays or using enzyme reactions to measure clinical chemistry analytes. The potential applications have an extremely wide span in research, screening and clinical diagnostics. The technique is extensively described in scientific publications and is an integral part of the mariPOC test system. Thanks to the test system ease of use and bench-top size, it can be used in decentralized testing and physician office labs (POLs) for delivering fast screening and diagnostic results. This enables optimizing patient care and hospital processes.

Key Advantages

TechnologyPlatform outcome
Separation free fluorescence measurement with dry-stored reagentsOne-step assay
Simple and compact automation
Robust reagent storage
Ease of use
World class sensitivity and specificity
Real-time monitoring of reaction kinetics Majority of positive samples can be reported in 15-20 minutes
No compromise between result time and sensitivity in rapid testing
Accuracy and performance independent of the reaction volumeSmall reagent volumes and consumption
Ability to test multiple targets from one sample/swab
Microparticle solid-phase chemistryExcellent precision and robustness
Complete QC
Simple multisample cartridgeEase of use
No need to insert the cartridge separately for each sample
Wide dynamic rangeNo false negatives due to hook effect
Adjusting for matrix variancesCan be used also for complex samples such as stools
Autoverification of sample analysisMaximizes accuracy and robustness
Flags user errors
Automated detectionMinimizes human and reading errors
Remote device health monitoring and remote support

mariPOC is unique

Thanks to the unique features of the TPX assay technique and platform design, mariPOC is the only product on the market, which allows automated and multianalyte antigen detection at the point of sampling at reasonable cost. Alternative solutions are either too complex for decentralised testing, capable of analysing only one or few targets per sample, or too expensive for out-patient testing.

mariPOC utilizes the TPX assay technique for highly sensitive and extremely specific direct pathogen detection. Antigen detection takes advantage of the natural in vivo multiplication of pathogens in the human body which leads to detectable antigen levels in acute infections. The tests have been designed to precisely detect the contagious individuals. It does not return clinically false positive results as the ex vivo amplification of nucleic acids applied in PCR. The superior specificity is the unique feature of the mariPOC technique. It results from a combination of  sandwich immunoassay principle, polystyrene microparticle solid phase and the TPX detection technology.

mariPOC and TPX technology

mariPOC analyser automatically dispenses clinical sample, suspended in proprietary sample buffer, into parallel (in case of multianalyte tests) test reaction wells on a cartridge. The dry reagents are stored in the wells. On sample addition, the analyser shakes the cartridge to dissolve the reagents and start the incubation. Direct detection of pathogen antigens by sandwich immunoassay principle takes place on polystyrene microparticles as the solid reaction phase. At predefined time point(s), laser-excited (λex=1064 nm) fluorescence of individual microparticles (specific fluorescence) is measured one at a time by the microfluorometer analyserin a separation-free assay. Instead of having multiple replicate wells for each target to increase precision, the solid phase is replicated within an individual reaction well with thousands of particles. The fluorescence brightness of the particles is in direct proportion to the target concentration in the sample. Also, the fluorescence signal of the surrounding solution (unbound tracer and sample matrix) is recorded. This enables efficient elimination of matrix interferences and autoverification of sample analysis.

mariPOC Technology figure

An exquisite property of the TPX technology is that the fluorescent output, and hence accuracy and precision, are totally independent of the reaction volume. The only parameters affecting the signal strength are the concentrations of reagents and the target, and their affinity to bind to each other. This unique property enables the use of small amounts of reagent and testing multiple targets from one minute sample.

Finally, a sophisticated data reduction algorithm returns the quantitative test result, which is compared to a predefined cut-off or calibration curve, to define if the sample is positive or negative or denote its concentration, respectively. Thanks to the TPX technology, our products are extremely homogeneous from batch to batch with consistent sensitivity and specificity. The TPX technology is the new standard in rapid direct pathogen detection.

mariAST and TPX technology

mariAST utilizes the TPX technique for highly sensitive and extremely specific direct pathogen detection and antimicrobial susceptibility testing (AST). Thanks to the principle of culturing the bacteria and simultaneously monitoring the growth in real-time using specific immunoassay, mariAST provides the ultimate sensitivity of one CFU per assay. In a typical product, this corresponds to an initial concentration of 50 CFU/ml. This level of sensitivity cannot be exceeded even with PCR based products. The automation and specificity are similar to mariPOC applications. An output of the test is species specific bacterial growth curve and interpretation of the result, for instance, “positive for MRSA”.

Unlike in mariPOC where typically the target pathogens are inactivated and disintegrated, in mariAST the reaction environment supports bacterial growth. The more the bacteria grow, the more signal is generated, and the signal change is monitored in real-time. When the reaction is supplemented with an antimicrobial, only the bacteria resistant to the agent can grow and produce signal. The methodology is a fast version of golden standard broth microdilution (BMD) with the exception that BMD requires isolated strains, whereas mariAST can be tested from clinical samples. This makes mariAST unique and time-saving and unrivalled.


  • EP 2576059 / US 8,883,093 / JP 5716088 / RU 2568885 / CN 103068485 / BR 112012029958-1 Sealing of reaction cuvettes for bioaffinity assays
  • EP 1401962 / US 7,198,958 / JP 4382474 A method for increasing hydrophilicity of fluorescent label compounds
  • EP 1402263 / US 7,763,439 / RU 2296333 / JP 4340149 / CN 1257408 Two-photon absorbing dipyrromethene difluoride dyes and their applications
  • EP 1714139 / US 10295465 / RU 2362987 Use of two-photon excited fluorescence in assays of clinical chemistry analytes
  • CN109073554 Bioaffinity assay method utilizing two-photon excitation of fluorescence

Other patents pending.


ArcDia International Oy Ltd is interested in licensing new innovations associated with infectious disease diagnostics.

ArcDia™ TPX detection platform is also available for licensing. Ask for more information.