Microfluidic combined

Atkas, O., Aluru, N. R., A combined continuum/DSMC technique for multiscale analysis of microfluidic filters,... 

When elution chromatography is used in both dimensions, the valve configurations are similar for the different column combinations. However, when CE is utilized as the second dimension, other types of interfaces not based on valves have been implemented with unique advantages. These and the microfluidic implementation of sampling systems for chip-based two-dimensional separations will be discussed below. 

Apart from immunoassays, enzyme assays can also be used to detect certain substrates in a clinical diagnostic setting. The benefits of performing enzymatic assays on microchips are the analytical power and minimal reagent use in microfluidic systems combined with the selectivity and amplification factors that come with biocatalysis. 

In addition to absolute pressure measurements, pressure sensors can be used to determine flow rates when combined with a well-defined pressure drop over a microfluidic channel. Integration of optical waveguide structures provides opportunities for monitoring of segmented gas-liquid or liquid-liquid flows in multichannel microreactors for multiphase reactions, including channels inside the device not accessible by conventional microscopy imaging (Fig. 2c) (de Mas et al. 2005). Temperature sensors are readily incorporated in the form of thin film resistors or simply by attaching thin thermocouples (Losey et al. 2001). 

In this chapter we first discuss the fundamentals and the design aspects of an integrated optical YI sensor (Sect. 10.2), followed by a description of the experimental setup (Sect. 10.3). In the result section (Sect. 10.4) both protein and vims detection experiments are discussed. Section 10.5 demonstrates the use of microfluidic chips for efficient sample handling in combination with the YI sensor. This chapter concludes with a discussion on the prospects of the sensor for point-of-care diagnostics. 

It is often desirable to immobilize different biomolecules on different sensing elements in close proximity on the same nanophotonic sensor in the development of a multiplexed sensor. This is the case in the example of parallel ID photonic crystal resonators described in Sect. 16.4. Cross-contamination of biomolecules must be avoided in order to preserve high specificity. We have found that a combination of parylene biopatteming and polydimethylsiloxane (PDMS) microfluidics is a convenient means to immobilized multiple biomolecules in close proximity without cross-contamination as shown in Fig. 16.8. Parylene biopatteming is first used to expose only the regions of highest optical intensity of the nanosensor for functionalization. Second, a set of PDMS microfluidics is applied to the parylene-pattemed nanophotonic sensor, and the biomolecules to be attached... 

H. Irth A microfluidic-based enzymatic assay for bioactivity screening combined with capillary liquid chromatography and mass spectrometry. Lab Chip 2005, 5,... 

An alkaloid pain reliever, morphine, is an often abused drug. Chronoampero-metric MIP chemosensors have been devised for its determination [204]. In these chemosensors, a poly(3,4-ethylenedioxythiophene) (PEDOT) film was deposited by electropolymerization in ACN onto an ITO electrode in the presence of the morphine template to serve as the sensing element [204], Electrocatalytic current of morphine oxidation has been measured at 0.75 V vs AglAgCllKClsat (pH = 5.0) as the detection signal. A linear dependence of the measured steady-state current on the morphine concentration extended over the range of 0.1-1 mM with LOD for morphine of 0.2 mM. The chemosensor successfully discriminated morphine and its codeine analogue. Furthermore, a microfluidic MIP system combined with the chronoamperometric transduction has been devised for the determination of morphine [182] with appreciable LOD for morphine of 0.01 mM at a flow rate of 92.3 pL min-1 (Table 6). 

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