Nanofluidic technology

Nanofluidics is defined as the study and application of fluid flow in and around structures with features that measure less than 100 nm (1 nm = 10-9 m) in one or more directions. Fluids confined in these structures exhibit physical behaviours not observed in larger structures, such as those of micrometre dimensions and above.

Nanofluidics is becoming a major field of research and has been applied in microfluidic systems allowing for DNA manipulation, protein separation, sample pre-concentration and single molecule detection. The majority of current nanofluidic research is intended for bioengineering and biotechnology applications.1

Abionic succeeded in bringing together nanoengineering, biochemical and medical sciences, and to develop an unparalleled nanofluidic technology-based platform to offer patients the fastest point-of-care testing solutions using principles of traditional capture ELISAs.

Figure 1. Integration of a fluorescent immunoassay (cross-section through a nanofluidic biosensor)
Figure 1

Homogeneous nanofluidic immunoassays rely on the enhanced bimolecular interactions occurring inside the nanochannel.

Analytes bound to fluorescent detecting antibodies are captured with very high efficiency on the reading area of the sensor.

A washing step is not needed as the surface over volume ratio is extremely high, and non-specific background is negligible.

Figure 2 shows the dose-dependent increase of fluorescent signal in the kinetic measurements of the ferritin in biosensors.

In less than two minutes the kinetic curves reach mass transfer equilibrium for all doses spanning the clinically relevant range needed to perform iron deficiency diagnostics.2

Figure 2. Signal uptake of ferritin versus assay time for various ferritin concentrations spanning the clinically relevant range in nanofluidic biosensors.

A rapid signal uptake is observed in the abioSCOPE® device once the sample is deposited onto the capsule containing the sensors. Figure 2 shows a dose-dependent signal increase over time.

A plateau is reached after approximately 90 seconds, demonstrating the ultra-fast binding reaction between the capture area and the targeted analyses present at very low concentration.

Figure 2

References 1) Durand, N.; Biomolecular Diffusion in Nanofluidics. EPFL, Lausanne, 2010.2) Putallaz L, Sprunger Y van den Bogaard P, “Nanofluidic technology enables decentralized and rapid diagnostic testing”, Poster presented at the 2nd Swiss POCT Symposium, 2018

Analytical performances

Novel nanofluidic allergy (IgE) assay versus a reference method: a real-world comparison

A pivotal study published by Rothlisberger, S et al. demonstrated that the diagnostic decision taken by allergy expert was the same in 94.6 percent of the cases when the IgE serologic assays were performed on the abioSCOPE® device versus a reference laboratory method. This study demonstrated the clinical utility of Abionic's point-of-care IgE solutions to revolutionise the diagnosis workup of patients suffering from allergic disease.3

Table 1. Positive and negative percent agreements calculated in function of diagnostic made by allergy experts’ panel

The impact of using the point-of-care abioSCOPE® device in comparison with sending out blood samples to a clinical laboratory to measure IgE on a reference method was found to be negligible.

The agreement in the diagnostic decision was remarkably the same in more than 94 percent of the cases.

Table 1
Excellent correlation between test results on the abioSCOPE® device and a laboratory reference method

The scope of this study is to demonstrate the agreement of whole blood sample measurements on the abioSCOPE® with corresponding plasma sample measurements on the laboratory reference method ImmunoCAP total IgE (ThermoFisher Scientific) and to estimate the precision of the abioSCOPE® platform.4

Figure 3. Method comparison: total IgE on the abioSCOPE® (whole blood) vs ImmunoCAP (plasma)
Figure 3

Sixty-nine whole blood and corresponding plasma samples were analysed for total IgE on the abioSCOPE® device and a laboratory reference method (ImmunoCAP, ThermoFisher Scientific, Uppsala, Sweden).

Deming statistics were applied on the dataset. An excellent correlation was found between the two methods (Figure 3): the goodness of the fit was R2=0.91, the slope of the regression line was 0.93 and the intercept -0.49 in the range 2 to 1500 IU/mL of total IgE.

Pancreatic stone protein (PSP) has significant potential as ‘early marker’ for sepsis detection

Sepsis is one of the leading causes of death in the world. It is a life-threatening condition caused by a dysregulated host response to infection. The pancreatic stone protein (PSP) is a host protein biomarker produced by the pancreas in response to a sepsis-related organ dysfunction and has shown a great potential in the early identification of septic patients. Abionic has succeeded in bringing together an ultra-rapid nanofluidic based diagnostic platform and the PSP biomarker to offer a unique simple bedside test for the earliest and immediate detection of sepsis.4

Figure 4. PSP levels raise up early in the development of sepsis

Sepsis is a medical emergency and requires prompt answer – every hour counts!

Early detection of sepsis with timely, appropriate interventions increases the likelihood of survival. Unfortunately, sepsis manifests through various clinical signs and its early diagnosis is therefore still a major challenge for clinicians.

PSP level raises up to 24 hours before sepsis diagnosis early in the development of sepsis.

Its availability near the patient thanks to the abioSCOPE® will enable timely initiation of the optimal treatments upon recognition of septic patients and potentially save millions of lives.

Figure 4

References 3) Roethlisberger S.; Novel Nanofluidic IgE Assay versus a Reference Method: A Real-World Comparison. Int Arch Allergy Immunol. 2019 Jun 12 4) Abionic internal evaluation study report (data on file)