Microelectronic biosensor

To obtain a microelectronic biosensor, a biological substance has to be immobilized onto the gate insulator of the ISFET. 

Such microelectronic biosensor systems are really microanalytical sensor systems which have already reached the clinical market. 

For microelectronic biosensors a further problem is the immobilization procedure of enzymes. Again different approaches were tried including drop-on techniques [61], ink-jet printing [68], spray techniques [62], electropolymerization [64], lift-off techniques [63,66] and photolithographically patterned enzyme membranes [65]. 

A membrane for a DNA-probe of a microelectronic biosensor based on Langmuir-Blodgett (LB) diacetylene film with covalently bonded DNA has been developed [86]. Diacetylene films formed on the surface of oxidized silicon by the LB method were used for covalent immobilization of DNA molecules, using the standard W./V -dicyclohexylcarbodiimide... 

A biosensor is a synergic combination of analytical biochemistry and microelectronics. Biosensors have recently been considered as a highly potential field of scientific research. This is because development of biosensors is necessary for the realisation of implantable, integrated and intelligent devices for biochemical information [17]. Biosensors are analytical devices that respond selectively to analytes in a given sample and convert their... 

Keywords Integrated miniaturized sensor arrays, microfluidics, biosensors, microelectronic, microsystemtechnology. 

Integrated optical devices combine microelectronic production technology with the inherent advantages of optical sensing. Many of these developments are in an early state of research but a variety of optical biosensors can be realized in principle. Integrated optical device manufacturing is nowadays commercially available (IOT) and nearly all optical elements can be integrated and miniaturized on chip [24]. 

DNA biosensors are also of great interest for the future development of microelectronic sensors for the detection of biological compounds and antigens. DNA would act as a promoter between the electrode and the biological molecule under study. Recently, some electrochemical research has been done in this direction with the aim of studying the interaction of DNA immobilized on the electrode surface with substances in solution. 

Microfabrication has emerged from microelectronics manufacturing and is using its proven processes and process sequences. Additionally, specific methods have been developed to fabricate mechanical, electrical, optical, or sensor structures, which are characteristics of microfabrication. In order to stay within the scope of this book, only top-down methods, that is, the manufacture of smaller structures with higher functionality from larger structures by the use of subtractive methods, will be discussed. Bottom-up methods, which create larger structures by ordered arrangement of small units (molecules, nanoparticles), are still in their infancy and mainly employed for biosensors. 

Advances in microelectronic technology, combined with the specificity of interactions of biological molecules such as antibodies and receptors, have led to the development of biosensors where the signal generated by the molecular interaction is transdnced into electronic signals. Biosensors have applications in diagnostics where predefined molecular interactions are measnred. They can also be valuable in the research laboratory for the characterization of rates of biomolecnlar interactions. Biosensors based on... 

Efforts in the development of specific biosensors based on photonic structures derived from silicon are entering their second decade. While published examples to date show considerable promise - and unique features of three-dimensional silicon structures that can be used advantageously - much work remains in order to turn these devices from laboratory curiosities to robust, sensitive, and general biosensors deployable in real world situations. As stated at the outset of this chapter, however, a significant advantage of these materials is their ubiquity in the microelectronics industry. This depth of industrial knowledge should smooth the transition of PSi and other silicon-based photonic structures into the marketplace. 

The integration between the two different disciplines, micro-biology and microelectronics, poses an exciting and challenging goal for the present decade. The developments related to this area led to the invention of novelty devices and smart biosensors. 

The power of the microelectronic technology, and its usefulness to extreme and precise miniaturization enable the construction of highly sensitive, fast, and robust devices, which can provide exciting opportunities in the biosensors field as well as in the basic research on microorganisms. 

Bruce Hammock developed the section on new immunochemical techniques. These chapters describe investigation of disease resistance in plants neuronal development in insect embryos pesticide residue analysis for plant diagnostics and quarantine and the development of a biosensor for applying monoclonal antibodies and microelectronics for environmental analysis. 

A concept for a generic biosensor is introduced that is capable of measuring small molecules in environmental matrices. This sensor, the capacitive affinity sensor, makes use of a combination of antibody and microelectronic technologies. Sensor operation is demonstrated using sensors for hydrocortisone and pentachlorophenol as examples. Because of the mature nature of the critical technologies, sensors based on this design should be commercially available in the near future. 

Although several definitions of biosensor exist, we will use the word to mean a microelectronic device that measures the interaction of an analyte with a biologically produced molecule as part of the measurement system. Figure 1 is a block diagram of a generalized biosensor. The most critical element of the sensor is the box marked Transducer this is where the information about the analyte (i.e. the... 

Our goal is the development of a "user friendly" biosensor for small molecules such as pesticides. To reach this goal the sensor must have a number of characteristics. These include specificity, sensitivity, accuracy, precision, ruggedness and manufacturability. While they are for the most part self-explanatory, the characteristic of manufacturabilty deserves further comment. The best sensor is of little use if it cannot be mass produced at a reasonable cost. For this reason our search for a transduction mechanism for a biosensor has concentrated where possible on well proven technologies that lend themselves to mass production. The biosensor we present here combines two well established technologies antibodies and microelectronics. 

Electrochemical sensors have been used as the basis or as an integral part of many chemical and biosensor developments. The introduction of microelectrode assembly added a new dimension to electrochemical sensors, and, consequently, to chemical and biosensor research. In recent years, the advancement of microelectronic fabrication technology has provided new impetus to the development of micro or miniature electrochemical sensors. 

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