Sensors Microfluidic sensor

For catalyst testing, conventional small tubular reactors are commonly employed today [2]. However, although the reactors are small, this is not the case for their environment. Large panels of complex fluidic handling manifolds, containment vessels, and extended analytical equipment encompass the tube reactors. Detection is often the bottleneck, since it is still performed in a serial fashion. To overcome this situation, there is the vision, ultimately, to develop PC-card-sized chip systems with integrated microfluidic, sensor, control, and reaction components [2]. The advantages are less space, reduced waste, and fewer utilities. 

Fig. 13.19 MCR microfluidic sensor. Reprinted from Ref. 33 with permission. 2008 American Institute of Physics...

Campopiano, S. Bernini, R. Zeni, R. Sarro, P. M., Microfluidic sensor based on integrated optical hollow waveguides, Opt. Lett. 2004, 29, 1894 1896... 

Zhan, W., Alvarez, J., Crooks, R.M., A two-channel microfluidic sensor that uses anodic electrogenerated chemiluminescence as a photonic reporter of cathodic redox reactions. Anal. Chem. 2003, 75, 313-318. 

An example of the immobilization of antibodies on channel surfaces was presented by Eteshola and Leckband [395]. A microfluidic sensor chip was developed to quantify a model analyte (sheep IgM) with sensitivities down to 17 nM. This was achieved by first immobilizing a layer of bovine serum albumine (BSA) onto the channel wall, followed by specific adsorption of protein A to which the primary antibody for IgM was coupled covalently. This antibody could capture IgM, which was detected with the secondary antibody, labeled with horseradish peroxidase (Scheme 4.91). This enzyme catalyzes the conversion of the fluorogenic substrate 3-(p-hydroxyphenyl)propioni c acid into a fluorophore, which was quantified off-chip with a spectrofluorometer. The measured fluorescence signal was proportional to the analyte concentration in the test sample. 

Microcantilever-based sensors Microfluidics Microneedles Medical MEMS... 

A microfluidic sensor to detect fluorescently labelled DNA was developed by Khur and co-workers [29], Photopatteming was obtained with carbene-generating photobiotin and allowed fabrication of homogeneous regions of immobilized biotin and the control of the spatial distribution of DNAs in a microchannel-flow-based sensor. 

In recent years, amperometric-based microfluidic sensor has been demonstrated as a highly sensitive method for biomolecules detection. Combination of microfluidic techniques and amperometric component enables dynamic monitoring of the target molecules. 

Future work shall be focused on two aspects (1) increase of the sensitivity of the amperometric microfluidic sensor and (2) multiple analysis of biomolecules. For the first aspect, new... 

Capacitance-based microfluidic sensors characterize micro-/nanoparticles or cells by measuring capacitance change using integrated electrically charged and isolated pair electrodes in a microfluidic chip. 

Capacitance-based microfluidic sensors have emerged as a powerful tool and been widely used in sensing pressure, position, biological cells, etc., since it has many advantages such as low cost and being compact, which makes capacitance-based microfluidic sensors of great potential use for point-of-care diagnosis. In this short entry, the mechanism, current applications, limitations, and perspectives of capacitance-based microfluidic method are introduced in details. 

It has been known that the electric double layer (EDL) presents large capacitance per unit area at the interface between an electrode and electrolyte. Based upon this mechanism, the capacitance-based application like energy storages and digital microfluidic sensor has been... 

Capacitance-Based Microfluidic Sensors, Fig. 8 Experimental setup schematic for measuring electrode capacitance and droplet position... 

Despite many advantages of capacitance-based microfluidic sensor such as cost-effectiveness, portability, etc., the major concern remaining is the integration of the readout electronics. In the mentioned systems above, IDEs are easily able to be... 

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