Immunosensors dispersion

FIGURE 54 A schematic of hie flow-through immunosensor equipped with (1) fluid inlet, (2) carbon current collector, (3) disposable immuno-column, (4) highly dispersed antibody-modified carbon particles (immunosorbent), (5) carbon counter electrode, (6) Ag AgCl reference electrode and (7) fluid outlet. (Reprinted from [16] with permission from Elsevier.)... 

SPR is a representative physical phenomenon that is widely utilized for label-free characterization of molecules on thin metal films. The basic principle and operation of SPR has been described in more detail in several review articles [77, 78]. The reports on SPR-based immune sensors have steeply increased for detection of analytes with low molecular weights in recent years. SPR detection in microfluidic systems can provide various advantages. Immunoreactions are completed within a short time due to small sample volumes down to the nanolitre scale. Kim et al. developed a simple and versatile miniaturized SPR immunosensor enabling parallel analyses of multiple analytes [79]. Their SPR sensor was claimed to exhibit good stability and reusability for 40 cycles and more than 35 days. Feltis et al. demonstrated a low-cost handheld SPR-based immunosensor for the toxin Ricin [80]. Springer et al. reported a dispersion-free microfluidic system with a four-channel SPR sensor platform, which considerably improved the response time and sensitivity [81]. The sensor was able to detect short sequences of nucleic acids down to a femtomole level for 4 min. Waswa et al. demonstrated the immunological detection of E. coli 0157 H7 in milk, apple juice, and meat juice extracted from... 

Staphylococcal protein A Amperometric immunosensor. Anti-protein A antibodies immobilized on dispersed C-powder... 

An immunosensor based on amine-functionalized CNT-SPE was described for detection of the cardiac troponin T, an important marker of acute myocardial infarction. The disposable sensor was fabricated by squeezing an adhesive carbon ink containing carbon nanotubes onto a polyethylene terephthalate substrate forming a thin film. The use of CNTs increased the reproducibility and stability of the sensor, and the amine groups permitted a nonrandom immobilization of antibodies against cardiac troponin T. Another example of the use of carboxylated CNTs is found by the work presented by Rafiee and Fakhari, who prepared a composite based on CNTs and Nafion for the development of a biosensor for the determination of insulin. Carboxylated CNTs plus Nafion were dispersed in water under ultrasonic conditions to get a homogeneous suspension and then a certain volume of that dispersive solution was dropped on the carbonaceous surface of the SPE. 

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