Microfluidic Electrochemical Sensors

The study of small microfluidic systems convey the design of reactors, chemical synthesis, and biochemical tests. However, the detection of the target molecule is also a matter that researchers and developers of new systems have to cover. Here, we will summarize the most important features regarding the detection during microfluidic operation. Chemyx syringe pump systems are optimized devices that can help you to achieve your goals as we will show in the following article.

 

Sensitive detection during microchip electrophoresis operation (case of success).

Which system can be studied?

The detection of a rhodamine B and catechol as electroactive molecules is possible through a Microchip. Eventually, the procedure was tested for the separation of two neurotransmitters such as dopamine and catechol. In this case, it is possible to establish a method to separated complex samples by pressure or vacuum (Dossi et al., 2010)⁠.

Electrophoresis procedures rely on hydrodynamic injection, which is necessary to avoid problems regarding electrokinetics during microchip detection. The Chemyx 200  allows a sample injection and a suitably distributed electric field during the records. Adjusting the parameters is possible to detect the target molecules (rhodamine,dopamine, and catechol) with 700 V, almost immediately after the injection.

 

How to achieve precision in this system?

The Fusion 200 allows a flow rate of 8 mL/min for 6 seconds and applies it to the injection channel. A very important feature that the 200 model offers during the hydrodynamic injections was a minimum flow rate of 1 nL/h.

The proposed injection method resulted in a fast operative procedure; moreover, it allows the feeding of analytes in the nanoliter range, in this way the injection and the detection are finely coupled. The syringe pump allows high sensitivity with outstanding simplification during operation.

 

What else can I do with Microfluidic Electrochemical Sensors?

Impedance microfluidic electrochemical sensors

Other microfluidic electrochemical sensors work with impedance; this technique allows the sensitive detection of classical passivated compounds like mercaptohexanol and polyethylene glycol. However, it can be used for the detection of target macromolecules as the cAMP receptor protein, tumor necrosis factor R, and tumor necrosis factor β. Each of the presented molecules generates a distinctive footprint in an impedance plot. Allowing, the fast characterization of various surface interactions, through this principle it is possible to select optimal functions for any microfluidic biosensor (Dykstra et al., 2011)⁠. If several macromolecules need to be detected a Chemyx Fusion 4000 with Independent Channels may be used for that purpose.

 

Detection of Simultaneous Hypertension Biomarkers with Microfluidic Electrochemical Sensor

Lee et al., 2017, presented a new design with four chambers coupled to an electrochemical sensor which detects isoprostane, adiponectin, fibrinogen, LDL through an immunoaffinity layer.  Each of the chambers receives the sample and allows the successful identification of the factors. During the study, no syringe pump was used. However, a Chemyx syringe pump can do this tasks without a problem. This approach may allow the construction of other sensors like this for DNA and RNA hybridization, any other biochemical phenomena can be studied.

 

Concluding Remarks

Chemyx 200 and Chemyx Fusion 4000 are powerful and robust pumps that allow the study of microfluidics. Furthermore, these devices can be coupled to microfluidic electrochemical sensors, proving smooth operation with different flow Rates from 0.001 µL/min to 102 mL/min ( Fusion 4000) and 1.6 pL/min to 102 mL/min (Fusion 4000). Additionally, they can operate at high pressure for electrophoretic procedures and electrochemical detection at the same time. In this small review, the relevance of a proper pumping control was explained, and the cases of literature show several opportunities for the study and the design of new microfluidic devices.

 

Bibliography

Dossi, N., Toniolo, R., Susmel, S., Pizzariello, A., Bontempelli, G., 2010. A simple approach to the hydrodynamic injection in microchip electrophoresis with electrochemical detection. Electrophoresis 31, 2541–2547. https://doi.org/10.1002/elps.201000089

Dykstra, P.H., Roy, V., Byrd, C., Bentley, W.E., Ghodssi, R., 2011. Microfluidic Electrochemical Sensor Array for Characterizing Protein. Anal. Chem. 5920–5927. https://doi.org/10.1021/ac200835s

Lee, G.H., Lee, J.K., Kim, J.H., Choi, H.S., Kim, J., Lee, S.H., Lee, H.Y., 2017. Single Microfluidic Electrochemical Sensor System for Simultaneous Multi-Pulmonary Hypertension Biomarker Analyses. Sci. Rep. 7, 1–8. https://doi.org/10.1038/s41598-017-06144-9

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