Sensor chip

Fig.Sa-f. The sensorgram of the repeated injection of the aqueous viologen dimer 2 (a, c, e) and the antibody (b, d, f) solutions. [Viologen dimer 2]=2.0 pM and [antibody]=2.0 pM in phosphate borate buffer. Injection period 60 s for a-c and 120 s for d-f. A solution of viologen dimer 2 or the antibody passes over the surface of the sensor chip for 60 or 120 s at a constant flow rate of 20 pL min. The surface of the sensor chip was subsequently washed with buffer...

The amount of antibody immobilized on the sensor chip decreased with increasing concentration of methyl viologen. To enlarge the difference in the sig-... 

Fig. 7. A proposed structure of the complex of the antibody with the trivalent antigen immobilized on the surface of the sensor chip...

Fig. 12a,b. The sensorgrams for the binding of the antibody dendrimer (a) or IgG (b) to the anionic porphyrin immobilized onto the surface of the sensor chip. Phosphate borate buffer (0.1 M, pH 9.0) was used. TCPP was immobilized via hexamethylenediamine spacer onto the sensor chip and then a solution of IgG or the dendrimer was injected to the flow cell. After 60 s from the injection of the antibody solutions, flow ceU was filled with buffer... 

Fig. 13a-e. The increase of the signal intensities by the addition of the dendritic complexes composed of IgGs and protein A. The hapten was immobilized to the surface of the SPR sensor chip. The increase of the signal intensities on the complex formation of hapten with the antibodies were monitored. The addition of mouse IgG specific for hapten (Abl) (a), the complex of the Abl with protein A (b), one to one complex of Abl with anti-mouse IgG (Fc) antibody (Ab2) (c), two to one complex of Abl with Ab2 (d), and two to one complex of Abl with Ab2 in the presence of protein A (e)... 

An enhancement of SPR signal intensity was observed by the addition of the antibody to the divalent antigen-antibody complex immobilized onto the surface of the sensor chip, indicating the formation of linear supramolecules. An amplification method of the detection signals for a target molecule has been... 

BIAlite system. Sensor Chip CMS, HBS buffer (lOmM H es, pH 7.4, 150 mM NaCl, 0.005% v/v surfactant p20 in distilled water), amine coupling kit were fi-om Pharmacia Biosensor (Uppsala, Sweden). 

The instrument consists of a procesmg unit, reagents for Ugand immobilization, exchangeable sensor chips and a personal con uter for control and evaluation. 

The sensor chip is held in contact with the prism of the optical system by a microfluidic cartridge that controls the delivery of sample plugs into a tran ort buffer that passes continuously over the sensor chip surfiice. 

Figure 7.9. Schematic diagram of a surface plasmon resonance biosensor. One of the binding partners is immobilized on the sensor surface. With the BIACORE instrument, the soluble molecule is allowed to flow over the immobilized molecule. Binding of the soluble molecule results in a change in the refractive index of the solvent near the surface of the sensor chip. The magnitude of the shift in refractive index is related quantitatively to the amount of the soluble molecule that is bound.

Jonsson, U., Fagerstam, L., Ivarsson, B., Johnsson, B., Karlsson, R., Lundh, K., Lofas, S., Persson, B., Roos, H., Ronnberg, I., Sjolander, S., Stenberg, E., Stahlberg, R., Urbaniczky, S., Ostlin, H., and Malmqvist, M. (1991). Real-time biospecific interaction analysis using surface plasmon resonance and a sensor chip technology. Biotechniques 11, 620-627. 

A smart sensor chip was presented by Texas Instruments171. It includes an LED light source, a photodiode, a chemically sensitive waveguide and an inert reference waveguide. It is schematically shown in Figure 7. 

A sensor configuration employing these cones is shown in Figure 15 Fluorescence from the luminescent spots is excited from behind the platform using an appropriate source (LED s in this case), is subsequently emitted via total internal reflection through the sensor chip and is detected by a CMOS camera, which is positioned behind the chip. For the purposes of intensity comparisons, luminescent spots are also deposited directly onto the planar surface of the chip and excited along with those deposited on the cones. 

In this case, the maximum enhancement is achieved when A,rcs is equal to the peak emission wavelength of the fluorophore. This enhancement is far more significant for fluorophores of low QE than for those of higher QE. An additional effect namely, a metal-fluorophore quenching can also occur for very small NP-fluorophore separations, typically within 5nm. This has important implications for the fabrication of an enhanced sensor chip, as will be seen in the following section. 

It is important to note that the enhancements mentioned above are achievable using current planar microfabrication techniques and the resultant sensor chips are mass-producible, low-cost and disposable and also have the potential to be integrated into a variety of diagnostic microsystems. This work has significant implications for the production of low-cost, yet efficient measurement platforms for applications in modem society. 

Malins C., Hulme J., Fielden P.R., Goddard N.J., Grating coupled leaky waveguide micro channel sensor chips for optical analysis, Sensor. Actuat. B-Chem 2001 77 671 -678. 

Figure 9. Cross-section of a refractive index sensor based on a quasi one-dimensional photonic crystal with grating period A = 190 nm. The top cladding over the grating is formed by a fluid contained in a cuvette that is sealed to the sensor chip.

Figure 12. Schematic lay-out of compact optical sensor chip without need of external optical apparatus with identical microresonators as sensors LED broad band source, for example Light Emitting Diode, MR-F microresonator used as optical filter, MR-S microresonator used as optical sensor, PD Photo Diode.

Challenges remain in the development of lab-on-a-chip sensing systems. The overall lifetime of a sensor chip is always determined by the sensor with the shortest lifetime, which in most cases is the depletion of reference electrolytes. Measures to minimize cross-talking among sensors, especially when biosensors are integrated in the system, also should be implemented [122], The development of compatible deposition methods of various polymeric membranes on the same chip is another key step in the realization of multisensing devices. 

Fig. 3.27 KAMINA gas sensor chip with gradient microarray mounted in its housing.

Description > j K-ssries pressura ssrt ofs feature LPSi-NT Series and MPSi-NT Series pressure sensor chips mourned cn TOB-headers. 

---