Microfluidic quartz-crystal-microbalance (QCM) sensors with specialized immunoassays for extended measurement range and improved reusability

Thies, J.-W.; Kühn, Philipp; Thrmann, B.; Dbel, S.; Dietzel, Andreas

doi:10.1016/j.mee.2017.04.023

Cited by 28 publications

(21 citation statements)

References 21 publications

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“…This leads to a higher resonant frequency drop and allows us to measure concentrations that were not measurable before. We already presented this approach in Thies et al (2017) and could increase our limit of detection to one microgram of CRP per millilitre of sample.…”

Section: Measurements and Resultsmentioning

confidence: 99%

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Low-cost, in-liquid measuring system using a novel compact oscillation circuit and quartz-crystal microbalances (QCMs) as a versatile biosensor platform

Beißner

Thies

Bechthold

et al. 2017

J. Sens. Sens. Syst.

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Abstract. Quartz-crystal microbalances (QCMs) are commercially available mass sensors which mainly consist of a quartz resonator that oscillates at a characteristic frequency, which shifts when mass changes due to surface binding of molecules. In addition to mass changes, the viscosity of gases or liquids in contact with the sensor also shifts the resonance but also influences the quality factor (Q-factor). Typical biosensor applications demand operation in liquid environments leading to viscous damping strongly lowering Q-factors. For obtaining reliable measurements in liquid environments, excellent resonator control and signal processing are essential but standard resonator circuits like the Pierce and Colpitts oscillator fail to establish stable resonances. Here we present a lowcost, compact and robust oscillator circuit comprising of state-of-the-art commercially available surface-mount technology components which stimulates the QCMs oscillation, while it also establishes a control loop regulating the applied voltage. Thereby an increased energy dissipation by strong viscous damping in liquid solutions can be compensated and oscillations are stabilized. The presented circuit is suitable to be used in compact biosensor systems using custom-made miniaturized QCMs in microfluidic environments. As a proof of concept we used this circuit in combination with a customized microfabricated QCM in a microfluidic environment to measure the concentration of C-reactive protein (CRP) in buffer (PBS) down to concentrations as low as 5 µg mL −1 .

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Section: Measurements and Resultsmentioning

confidence: 99%

“…A printed circuit board (PCB) is used as a carrier and allows for connection to the oscillation circuit. The detailed fabrication process can be found in Thies et al (2017).…”

Section: Microfluidic Chip With Integrated Qcm Devicesmentioning

confidence: 99%

Low-cost, in-liquid measuring system using a novel compact oscillation circuit and quartz-crystal microbalances (QCMs) as a versatile biosensor platform

Beißner

Thies

Bechthold

et al. 2017

J. Sens. Sens. Syst.

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“…For this study, custom microfabricated QCM devices with flow cell embedding are made from PDMS ( Figure 1 ), as described earlier [ 9 ]. For injecting fluids into the microsystem, a pulsation-free syringe pump (Nemesys syringe pump, Cetoni GmbH, Korbussen Germany) is used.…”

Section: Methodsmentioning

confidence: 99%

“…These additional molecules and/or particles bind to the substance to be measured, which results in a bigger frequency change [ 8 ]. In a previous work [ 9 ], we utilized an especially designed CRP antibody sandwich with a fast off-rate. There, the dissociation of the CRP complex happened spontaneously without the need for additional elution steps, allowing for faster analysis and reducing the consumption of chemicals.…”

Section: Introductionmentioning

confidence: 99%

Particle-Based Microfluidic Quartz Crystal Microbalance (QCM) Biosensing Utilizing Mass Amplification and Magnetic Bead Convection

et al. 2018

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Microfluidic quartz crystal microbalances (QCM) can be used as powerful biosensors that not only allow quantifying a target analyte, but also provide kinetic information about the surface processes of binding and release. Nevertheless, their practical use as point-of-care devices is restricted by a limit of detection (LoD) of some ng/cm². It prohibits the measurement of small molecules in low concentrations within the initial sample. Here, two concepts based on superparamagnetic particles are presented that allow enhancing the LoD of a QCM. First, a particle-enhanced C-reactive protein (CRP) measurement on a QCM is shown. The signal response could be increased by a factor of up to five by utilizing the particles for mass amplification. Further, a scheme for sample pre-preparation utilizing convective up-concentration involving magnetic bead manipulation is investigated. These experiments are carried out with a glass device that is fabricated by utilizing a femtosecond laser. Operation regimes for the magnetic manipulation of particles within the microfluidic channel with integrated pole pieces that are activated by external permanent magnets are described. Finally, the potential combination of the concepts of mass amplification and up-concentration within an integrated lab-on-a chip device is discussed.

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“…QCM sensors can operate in gas and liquid environments to determine the properties of chemicals [33] . Along with sensitive biosensors, they can detect even a nanogram of substance [34] .…”

Section: Quartz Crystal Microbalance (Qcm) Sensorsmentioning

confidence: 99%

Electronic Nose and Its Applications: A Survey

Karakaya

Ulucan

Türkan

2019

Int. J. Autom. Comput.

248

152

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In the last two decades, improvements in materials, sensors and machine learning technologies have led to a rapid extension of electronic nose (EN) related research topics with diverse applications. The food and beverage industry, agriculture and forestry, medicine and health-care, indoor and outdoor monitoring, military and civilian security systems are the leading fields which take great advantage from the rapidity, stability, portability and compactness of ENs. Although the EN technology provides numerous benefits, further enhancements in both hardware and software components are necessary for utilizing ENs in practice. This paper provides an extensive survey of the EN technology and its wide range of application fields, through a comprehensive analysis of algorithms proposed in the literature, while exploiting related domains with possible future suggestions for this research topic.

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Microfluidic quartz-crystal-microbalance (QCM) sensors with specialized immunoassays for extended measurement range and improved reusability

Cited by 28 publications

References 21 publications

Low-cost, in-liquid measuring system using a novel compact oscillation circuit and quartz-crystal microbalances (QCMs) as a versatile biosensor platform

Low-cost, in-liquid measuring system using a novel compact oscillation circuit and quartz-crystal microbalances (QCMs) as a versatile biosensor platform

Particle-Based Microfluidic Quartz Crystal Microbalance (QCM) Biosensing Utilizing Mass Amplification and Magnetic Bead Convection

Electronic Nose and Its Applications: A Survey

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