Laser-Based Biosensors

Several popular laser-based biosensors, SPR, optic fibers, waveguides, and microcantilever biosensors, will be summarized below. 

A planar waveguide with a corrugated surface, which can be tuned to be a resonant Bragg reflector, is also a laser-based biosensor (Fig. 6) [8]. 

Biosensors Using Lasers, Fig. 6 Schematic of a laser-based biosensor using the resonant Bragg reflector principle. A receptor molecular layer covers the surface of some corrugation that is used as sensing materials. After some... 

In recent years, laser-based biosensors have become important tools in many fields such as analytical biochemistry, pharmaceutical research and development, and food/environ-mental monitoring. However, the volumes of the optic components in these biosensors limit their application in portable microdevices. In order to obtain more powerful, miniaturized, and cheaper biosensors using lasers, novel biological sensing principles, detection means, and fabrication methods need to be sought. The integration of biosensors and microfluidic chips will be an important direction for developments in laser-based biosensors. Biosensors can be used as microscale detection tools in lab-on-a-chip for the research and development of miniaturized detection devices, i.e., micro-total analysis systems. 

Many laser-based biosensors are derived from traditional detection methods. For example, traditional enzyme-based biological sensing analyses use the photometric detection... 

In recent years, laser-based biosensors have become important tools in many fields such as analytical biochemistry, pharmaceutical research and development, and food/environmental monitoring. However, the volumes of the optic components in these biosensors limit their application in portable microdevices. In order to obtain... 

The requirement of near-UV excitation for BFPs can be a limiting factor. A possible solution would be to use two-photon excitation alternatively a 405 nm diode laser could be used for excitation of BFP. A unique advantage of the BFP/GFP FRET-pair in principle is that it can be used in combination with a red-shifted VFP FRET pair. This enables the simultaneous expression of two different FRET-based biosensors (see Chapter 6). 

In a second experiment, Cy5-labelled antiBSA antibodies were immobilised on a silanised glass slide precoated with metallic nanoislands using a polydimethylsiloxane (PDMS) flow-cell. The antibody solution was left for 1 hour to attach and then the cell was flushed with deionised water. The slide was then dried with N2. For this experiment, a portion of the slide was not coated with metallic nanoislands, in order to act as a reference. Figure 20 shows the image recorded using the fluorescence laser scanner mentioned previously. The enhancement in fluorescence emission between those areas with and without nanoislands (B and A, respectively) is again evident. For both chips, an enhancement factor of approximately 8 was recorded. There is considerable interest in the elucidation and exploitation of plasmonic effects for fluorescence-based biosensors and other applications. 

The idea behind a spintronic biochip or biosensor is to replace traditionally used fluorescent markers by magnetic labels. Instead of detecting biomolecular recognition using expensive optical or laser-based... 

Patterns of viable E. coli bacteria have been transferred onto various substrates with laser-based forward transfer technique. Tliese tools can be used to create three-dimensional mesoscopically engineered shnctures of living cells, proteins, DNA strands and antibodies and to CO fabricate electronic devices on the same substrate to generate cell-based biosensors and bioelectronic interfaces and implantates. ... 

As a laser-based optical biosensor technique, SPR can measure molecular binding events at a metal surface by detecting changes in the local refractive index. The depth probed at the metal-aqueous interface is typically 200 nm, making SPR a surface-sensitive technique ideal for studying interactions between immobihzed biological molecules and a solution-phase anal3he. 

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