Real-time detection

Mortensen, A. and L. H. Skibsted. 1997b. Real time detection of reactions between radicals of lycopene and tocopherol homologues. Free Rad. Res. 27 229-234. 

Ni F., Sheng R.S., Cotton T.M., Flow-injection analysis and real-time detection of RNA bases by surface-enhanced Raman-spectroscopy, Anal. Chem. 1990 62 1958-1963. 

Due to their response mechanism the polyion-selective electrodes are not sensitive to the small fragments of polyionic macromolecules. Thus, if an enzyme cleaves the polyionic molecule these sensors can be used for detection of enzyme activity. Polycation protamine is rich in arginine residues that make it a suitable substrate for protease-sensitive electrochemical assays. Real-time detection of trypsine activity was demonstrated with the protamine-selective electrode as a detector [38],... 

Electrochemical biosensors are analytical devices in which an electrochemical device serves as a transduction element. They are of particular interest because of practical advantages, such as operation simplicity, low expense of fabrication, and suitability for real-time detection. Since the first proposal of the concept of an enzyme-based biosensor by Clark, Jr [1], significant progress in this field has been achieved with the inherited sensitivity and selectivity of enzymes for analytical purposes. 

G. Langergraber, J. van den Broeke, W. Lettl, A. Weingartner, Real-time detection of possible harmfnl events nsing UV/vis spectrometry. Spectroscopy Europe, 18(4), 19-22 (2006). 

The SeaDog sensor utilized in this work is capable of near real-time detection of low concentrations of explosives in water. The sensor utilizes novel sensing materials originally developed by collaborators at MIT. These materials are fluorescent polymers that are highly emissive when deployed as solid-state thin films. When the polymers interact with nitroaromatic explosives such as TNT, the fluorescence is quenched [3-5], The response of these materials to target analytes... 

Dock, M., M. Fisher, and C. Cumming. Sensor for real-time detection of underwater unexploded ordnance, in Proceedings of UXO/Countermine Forum 2002, September 2002, Orlando, Florida. 

Use of optical fiber biosensors for real-time detection of biowarfare agents (BWA) especially those of bacterial cells, toxins, or spores in the air, soil, or environment has been investigated by the Naval Research Laboratory (Taitt et al, 2005). In addition, many laboratories are also employing fiber optic biosensors for detection of wide varieties of foodbome pathogens, which are discussed below. 

Upadhyay, P., Patra, A. K., Mukhopadhyay, R., and Panda, A. K. (2001). Real time detection and quantification of inclusion bodies expressed in Escherichia coli by impedance measurements. Biotechnol. Lett. 23, 839-843. 

Schnerr, H., Niessen, L., and Vogel, R. F. (2001). Real time detection of the triS gene in Fusarium species by LigthCycler-PCR using SYBR Green 1 for continuous fluorescence monitoring. Int. J. Food Microbiol. 71, 53-61. 

Buckley J.B. French, The Real Time Detection of Trinitrotoluene in Ambient Air Using TAG A System , UTIAS Tech, 213, 7 (1977)... 

E. Mauriz, A. Calle, L.M. Lechuga, J. Quintana, A. Montoya and J.J. Manclus, Real-time detection of chlorpyrifos at part per trillion levels in ground, surface and drinking water samples by a portable surface plasmon resonance immunosensor, Anal. Chim. Acta, 561 (2006) 40-47. 

However, real-time detection requires access to a special real-time PCR cycler, which is able to detect the increase/decrease of added fluorescence labels during DNA amplification. Although these machines are more and more common for quantitative DNA analysis, their availability in clinical laboratories is still limited. Therefore, the following subsections also include a detailed overview of the classical approaches to quantitative (I)PCR amplificate, analysis which exchanges less demanding PCR equipment for additional hands-on time. The sensitivity of real-time or end-point IPCR detection is quite similar. A comparison of the influence of different endpoint detection methods to the overall sensitivity of IPCR is given in Fig. 5. 

A major breakthrough in the development of quantitative PCR was the invention of real-time detection methods for DNA amplification product during PCR [63], In this technique, a fluorescence-generating probe (e.g., a Taq-man probe, see Fig. 7A) is added to the PCR mix. During amplification of the DNA template, the probe is modified/degraded, so that an initially quenched fluorescence increases parallel to the increased amount of amplified DNA. As a less specific alternative, an intercalation marker could be added to the PCR mix, which incorporates in the double-stranded PCR product and thereby increases fluorescence during PCR. 

The major drawback of the real-time method IPCR is the need for a specialized real-time cycler, preferably compatible to the microplate format. With the increasing distribution of these machines, there is also an emerging range of new opportunities for real-time IPCR. The need of an additional fluorescent probe during PCR is compensated for by the fact that all materials and reagents for post-PCR processing were no longer required. However, the need for separate discriminable fluorescence probes reduces the usefulness of real-time detection in multiplex IPCR applications. 

For the detection of CEA in human blood serum, as well as for the detection of prions (see also Section 3.4) Niemeyer et al. applied the one-step DDI-IPCR [60] described above (2.1.4). This method combines the advantages of coupling the antigen in solution, effective hybridization-directed immobilization, IPCR signal amplification, and real-time detection (2.2.3) into a very fast and robust protocol with a 1000-fold sensitivity increase over conventional ELISA. 

Consumption of organic solvents avoided. Direct analysis of contaminants in water Minimal, noncontaminating waste Faster analysis real-time detection and high throughput Availability of portable biosensor systems Applicable to early-warning and on-site monitoring Nonqualified personnel required user-friendly Equipment cost-effective... 

Basic concepts of femtochemistry, i.e., the real-time detection and control of chemical dynamics. 

Recently, two basic questions of chemical dynamics have attracted much attention first, is it possible to detect ( film ) the nuclear dynamics directly on the femtosecond time scale and second, is it possible to direct (control) the nuclear dynamics directly as it unfolds These efforts of real-time detection and control of molecular dynamics are also known as femtosecond chemistry. Most of the work on the detection and control of chemical dynamics has focused on unimolecular reactions where the internuclear distances of the initial state are well defined within, of course, the quantum mechanical uncertainty of the initial vibrational state. The discussion in the following builds on Section 7.2.2, and we will in particular focus on the real-time control of chemical dynamics. It should be emphasized that the general concepts discussed in the present section are not limited to reactions in the gas phase. 

Real-time monitoring of PCR amplification was achieved by sequential CGE after 15, 20, 25, and 30 s (see Figure 9.9) [924]. In addition, PCR of [i-aclin DNA (294 bp) has been integrated with real-time detection at 518 nm using a fluorescent reporter probe [943]. 

Bieche I, Olivi M, Champeme MH, Vidaud D, Lidereau R, Vidaud M. Novel approach to quantitative polymerase chain reaction using real-time detection application to the detection of gene amplification in breast cancer. Int J Cancer 1998 78(5) 661-666. 

Figure 2. Neon spectra (hollow cathode emission) acquired with an SIT detector cooled to —50°C. (a) Real-time detection, 20 ms/scan, neutral density filter (ND) = 0 (b) Readout, after signal integration for 20 seconds (c) Integration equivalent to 10s scan periods. ND filter = 5 (0.001% transmission) was used to attenuate the signal. Equivalent dark spectra were subtracted from each neon...

---